feat(authentik): enhance OIDC flow with new logout redirect and branding support

- Added a new blueprint for OIDC logout that invalidates the Authentik session and redirects to a specified landing page.
- Introduced custom CSS and JS files for branding, improving the visual integration of Authentik flows.
- Updated Nginx configuration to serve the new branding assets and handle specific routes for signup and password recovery.
- Enhanced the flow completion logic to support OIDC bridge functionality, including session management and redirect handling.
- Implemented unit tests for the new OIDC bridge and flow context functionalities to ensure reliability.

deploy/authentik/blueprints/01-ulti-enrollment.yaml

@@ -28,20 +28,6 @@ entries:
       placeholder_expression: false
       order: 0
 
-  - model: authentik_stages_prompt.prompt
-    id: ulti-enroll-field-domain-hint
-    identifiers:
-      name: ulti-enrollment-field-domain-hint
-    attrs:
-      field_key: domain_hint
-      label: Votre adresse sera
-      type: static
-      required: false
-      initial_value: "@ultisuite.fr"
-      initial_value_expression: false
-      placeholder_expression: false
-      order: 1
-
   - model: authentik_stages_prompt.prompt
     id: ulti-enroll-field-email-sync
     identifiers:
@@ -128,7 +114,6 @@ entries:
     attrs:
       fields:
         - !KeyOf ulti-enroll-field-email
-        - !KeyOf ulti-enroll-field-domain-hint
         - !KeyOf ulti-enroll-field-email-sync
         - !KeyOf ulti-enroll-field-password
         - !KeyOf ulti-enroll-field-password-repeat

deploy/authentik/blueprints/06-ulti-oidc-logout.yaml

@@ -0,0 +1,31 @@
+# UltiSuite — OIDC RP logout : invalide session Authentik + redirect landing
+version: 1
+metadata:
+  name: Ulti OIDC logout redirect
+  labels:
+    blueprints.goauthentik.io/instantiate: "true"
+entries:
+  - model: authentik_stages_redirect.redirectstage
+    id: ulti-logout-redirect
+    identifiers:
+      name: ulti-logout-redirect-suite
+    attrs:
+      mode: static
+      target_static: https://dev.ultispace.fr/
+      keep_context: false
+
+  - model: authentik_flows.flowstagebinding
+    identifiers:
+      target: !Find [authentik_flows.flow, [slug, default-provider-invalidation-flow]]
+      stage: !Find [authentik_stages_user_logout.userlogoutstage, [name, default-invalidation-logout]]
+      order: 0
+    attrs:
+      order: 0
+
+  - model: authentik_flows.flowstagebinding
+    identifiers:
+      target: !Find [authentik_flows.flow, [slug, default-provider-invalidation-flow]]
+      stage: !KeyOf ulti-logout-redirect
+      order: 10
+    attrs:
+      order: 10

deploy/authentik/blueprints/06-ulti-oidc-logout.yaml.template

@@ -0,0 +1,31 @@
+# UltiSuite — OIDC RP logout : invalide session Authentik + redirect landing
+version: 1
+metadata:
+  name: Ulti OIDC logout redirect
+  labels:
+    blueprints.goauthentik.io/instantiate: "true"
+entries:
+  - model: authentik_stages_redirect.redirectstage
+    id: ulti-logout-redirect
+    identifiers:
+      name: ulti-logout-redirect-suite
+    attrs:
+      mode: static
+      target_static: {{SUITE_ORIGIN}}/
+      keep_context: false
+
+  - model: authentik_flows.flowstagebinding
+    identifiers:
+      target: !Find [authentik_flows.flow, [slug, default-provider-invalidation-flow]]
+      stage: !Find [authentik_stages_user_logout.userlogoutstage, [name, default-invalidation-logout]]
+      order: 0
+    attrs:
+      order: 0
+
+  - model: authentik_flows.flowstagebinding
+    identifiers:
+      target: !Find [authentik_flows.flow, [slug, default-provider-invalidation-flow]]
+      stage: !KeyOf ulti-logout-redirect
+      order: 10
+    attrs:
+      order: 10

deploy/authentik/branding/ulti-authentik.js

@@ -0,0 +1,425 @@
+/**
+ * UltiSuite — enrichissements DOM des flows Authentik (shadow roots inclus).
+ * Actuellement : ulti-enrollment (suffixe e-mail, toggle mot de passe, robustesse).
+ */
+(function () {
+  "use strict";
+
+  const ENROLLMENT_SLUG = "ulti-enrollment";
+  const DEFAULT_MAIL_SUFFIX = "@ultisuite.fr";
+  const EMAIL_CHECK_DEBOUNCE_MS = 1000;
+  const MIN_EMAIL_LOCAL_LENGTH = 2;
+
+  const EYE_SVG =
+    '<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M2 12s3-7 10-7 10 7 10 7-3 7-10 7-10-7-10-7Z"/><circle cx="12" cy="12" r="3"/></svg>';
+  const EYE_OFF_SVG =
+    '<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M9.88 9.88a3 3 0 1 0 4.24 4.24"/><path d="M10.73 5.08A10.43 10.43 0 0 1 12 5c7 0 10 7 10 7a13.16 13.16 0 0 1-1.67 2.68"/><path d="M6.61 6.61A13.526 13.526 0 0 0 2 12s3 7 10 7a9.74 9.74 0 0 0 5.39-1.61"/><line x1="2" x2="22" y1="2" y2="22"/></svg>';
+
+  function forEachDeep(root, visit) {
+    if (!root) return;
+    visit(root);
+    const nodes = root.querySelectorAll ? root.querySelectorAll("*") : [];
+    for (const node of nodes) {
+      if (node.shadowRoot) forEachDeep(node.shadowRoot, visit);
+    }
+  }
+
+  function flowSlug(executor) {
+    return (
+      executor.getAttribute("flowslug") ||
+      executor.getAttribute("flowSlug") ||
+      ""
+    );
+  }
+
+  function mailSuffixFromForm(form) {
+    const hidden = form.querySelector('input[name="email"]');
+    const raw = hidden?.value || hidden?.getAttribute("value") || "";
+    const at = raw.indexOf("@");
+    if (at >= 0) return raw.slice(at);
+    return DEFAULT_MAIL_SUFFIX;
+  }
+
+  function mailDomainFromForm(form) {
+    const suffix = mailSuffixFromForm(form);
+    return suffix.replace(/^@+/, "");
+  }
+
+  function normalizeSignupLocalPart(raw) {
+    return String(raw || "")
+      .replace(/@+/g, "")
+      .trim()
+      .toLowerCase();
+  }
+
+  function evaluatePasswordStrength(password) {
+    if (!password) return { level: "empty", label: "" };
+    let score = 0;
+    if (password.length >= 8) score += 1;
+    if (password.length >= 12) score += 1;
+    if (/[a-z]/.test(password) && /[A-Z]/.test(password)) score += 1;
+    if (/\d/.test(password)) score += 1;
+    if (/[^A-Za-z0-9]/.test(password)) score += 1;
+
+    if (score <= 1) return { level: "weak", label: "Faible" };
+    if (score === 2) return { level: "fair", label: "Moyen" };
+    if (score === 3 || score === 4) return { level: "good", label: "Bon" };
+    return { level: "strong", label: "Fort" };
+  }
+
+  function activeSegments(level) {
+    if (level === "weak") return 1;
+    if (level === "fair") return 2;
+    if (level === "good") return 3;
+    if (level === "strong") return 4;
+    return 0;
+  }
+
+  function createStrengthMeter(input) {
+    const wrap = document.createElement("div");
+    wrap.className = "ulti-password-strength";
+    wrap.hidden = true;
+    wrap.setAttribute("aria-live", "polite");
+
+    const bars = document.createElement("div");
+    bars.className = "ulti-password-strength-bars";
+    for (let i = 0; i < 4; i += 1) {
+      bars.appendChild(document.createElement("span"));
+    }
+
+    const label = document.createElement("p");
+    label.className = "ulti-password-strength-label";
+    label.innerHTML = 'Robustesse : <strong class="ulti-password-strength-value"></strong>';
+
+    wrap.appendChild(bars);
+    wrap.appendChild(label);
+
+    const update = () => {
+      const { level, label: text } = evaluatePasswordStrength(input.value);
+      wrap.hidden = !input.value;
+      const segs = activeSegments(level);
+      bars.querySelectorAll("span").forEach((bar, index) => {
+        bar.className = index < segs ? `active ${level}` : "";
+      });
+      wrap.querySelector(".ulti-password-strength-value").textContent = text;
+    };
+
+    input.addEventListener("input", update);
+    update();
+    return wrap;
+  }
+
+  function createMatchIndicator(primary, repeat) {
+    const el = document.createElement("p");
+    el.className = "ulti-password-match";
+    el.hidden = true;
+    el.setAttribute("role", "status");
+
+    const update = () => {
+      const a = primary.value;
+      const b = repeat.value;
+      if (!b) {
+        el.hidden = true;
+        return;
+      }
+      el.hidden = false;
+      const ok = a === b;
+      el.className = ok ? "ulti-password-match ok" : "ulti-password-match bad";
+      el.textContent = ok
+        ? "Les mots de passe correspondent."
+        : "Les mots de passe ne correspondent pas.";
+    };
+
+    primary.addEventListener("input", update);
+    repeat.addEventListener("input", update);
+    update();
+    return el;
+  }
+
+  function wrapPasswordInput(input) {
+    if (input.closest(".ulti-password-wrap")) return input.closest(".ulti-password-wrap");
+
+    const wrap = document.createElement("div");
+    wrap.className = "ulti-password-wrap";
+    input.parentNode.insertBefore(wrap, input);
+    wrap.appendChild(input);
+    input.classList.add("ulti-password-input");
+
+    const btn = document.createElement("button");
+    btn.type = "button";
+    btn.className = "ulti-password-toggle";
+    btn.setAttribute("aria-label", "Afficher le mot de passe");
+    btn.innerHTML = EYE_SVG;
+    btn.addEventListener("click", () => {
+      const visible = input.type === "text";
+      input.type = visible ? "password" : "text";
+      btn.setAttribute(
+        "aria-label",
+        visible ? "Afficher le mot de passe" : "Masquer le mot de passe"
+      );
+      btn.innerHTML = visible ? EYE_SVG : EYE_OFF_SVG;
+    });
+    wrap.appendChild(btn);
+    return wrap;
+  }
+
+  function enhanceEmailField(form) {
+    const input = form.querySelector('input[name="username"]');
+    if (!input || input.closest(".ulti-email-input-group")) return;
+
+    form.querySelectorAll("p").forEach((p) => {
+      if (p.textContent.trim().startsWith("@")) p.hidden = true;
+    });
+
+    const group = document.createElement("div");
+    group.className = "ulti-email-input-group";
+    input.parentNode.insertBefore(group, input);
+    group.appendChild(input);
+
+    const suffix = document.createElement("span");
+    suffix.className = "ulti-email-suffix";
+    suffix.textContent = mailSuffixFromForm(form);
+    group.appendChild(suffix);
+
+    attachEmailAvailabilityChecker(form, input);
+  }
+
+  function attachEmailAvailabilityChecker(form, input) {
+    if (input.dataset.ultiAvailability === "1") return;
+    input.dataset.ultiAvailability = "1";
+
+    const hint = document.createElement("p");
+    hint.className = "ulti-email-availability";
+    hint.hidden = true;
+    hint.setAttribute("aria-live", "polite");
+
+    const host = input.closest("ak-form-element");
+    if (host) host.after(hint);
+
+    let debounceTimer = null;
+    let requestId = 0;
+    let debouncedLocal = "";
+    let status = "idle";
+
+    function submitButton() {
+      return form.querySelector(
+        '.pf-c-form__group.pf-m-action button[type="submit"]'
+      );
+    }
+
+    function setSubmitDisabled(disabled) {
+      const btn = submitButton();
+      if (!btn) return;
+      btn.disabled = disabled;
+      btn.setAttribute("aria-disabled", disabled ? "true" : "false");
+    }
+
+    function render(local) {
+      if (local.length === 0) {
+        hint.hidden = true;
+        input.removeAttribute("aria-invalid");
+        setSubmitDisabled(false);
+        return;
+      }
+
+      hint.hidden = false;
+      hint.className = "ulti-email-availability";
+
+      if (local.length < MIN_EMAIL_LOCAL_LENGTH) {
+        hint.classList.add("muted");
+        hint.textContent = "Au moins 2 caractères avant le @.";
+        input.removeAttribute("aria-invalid");
+        setSubmitDisabled(true);
+        return;
+      }
+
+      if (local !== debouncedLocal || status === "checking") {
+        hint.classList.add("checking");
+        hint.textContent = "Vérification de la disponibilité…";
+        input.removeAttribute("aria-invalid");
+        setSubmitDisabled(true);
+        return;
+      }
+
+      if (status === "available") {
+        hint.classList.add("ok");
+        hint.setAttribute("role", "status");
+        hint.textContent = "Cette adresse est disponible.";
+        input.removeAttribute("aria-invalid");
+        setSubmitDisabled(false);
+        return;
+      }
+
+      if (status === "taken") {
+        hint.classList.add("bad");
+        hint.setAttribute("role", "alert");
+        hint.textContent = "Cette adresse est déjà prise.";
+        input.setAttribute("aria-invalid", "true");
+        setSubmitDisabled(true);
+        return;
+      }
+
+      if (status === "error") {
+        hint.classList.add("muted");
+        hint.textContent =
+          "Impossible de vérifier la disponibilité pour le moment.";
+        input.removeAttribute("aria-invalid");
+        setSubmitDisabled(false);
+        return;
+      }
+
+      hint.hidden = true;
+      setSubmitDisabled(false);
+    }
+
+    async function runCheck(local) {
+      const domain = mailDomainFromForm(form);
+      const id = ++requestId;
+      status = "checking";
+      render(local);
+
+      try {
+        const params = new URLSearchParams({ local, domain });
+        const res = await fetch(
+          `/api/v1/mail/addresses/check?${params.toString()}`,
+          {
+            headers: { Accept: "application/json" },
+            credentials: "include",
+          }
+        );
+        if (id !== requestId) return;
+        if (!res.ok) throw new Error(`address check failed (${res.status})`);
+        const data = await res.json();
+        status = data.available ? "available" : "taken";
+      } catch {
+        if (id !== requestId) return;
+        status = "error";
+      }
+
+      render(normalizeSignupLocalPart(input.value));
+    }
+
+    function scheduleCheck() {
+      const local = normalizeSignupLocalPart(input.value);
+      window.clearTimeout(debounceTimer);
+
+      if (local.length < MIN_EMAIL_LOCAL_LENGTH) {
+        requestId += 1;
+        debouncedLocal = local;
+        status = "idle";
+        render(local);
+        return;
+      }
+
+      status = "checking";
+      render(local);
+
+      debounceTimer = window.setTimeout(() => {
+        debouncedLocal = local;
+        void runCheck(local);
+      }, EMAIL_CHECK_DEBOUNCE_MS);
+    }
+
+    input.addEventListener("input", scheduleCheck);
+    input.addEventListener("keydown", (event) => {
+      if (event.key === "@") event.preventDefault();
+    });
+    input.addEventListener("paste", (event) => {
+      const text = event.clipboardData?.getData("text") ?? "";
+      if (!text.includes("@")) return;
+      event.preventDefault();
+      input.value = normalizeSignupLocalPart(text);
+      input.dispatchEvent(new Event("input", { bubbles: true }));
+    });
+
+    scheduleCheck();
+  }
+
+  function enhanceEnrollmentForm(form) {
+    if (form.dataset.ultiEnhanced === "1") return;
+    if (!form.querySelector('input[name="username"]')) return;
+
+    form.dataset.ultiEnhanced = "1";
+    enhanceEmailField(form);
+
+    const password = form.querySelector('input[name="password"]');
+    const repeat = form.querySelector('input[name="password_repeat"]');
+    if (!password || !repeat) return;
+
+    wrapPasswordInput(password);
+    wrapPasswordInput(repeat);
+
+    const passwordHost = password.closest("ak-form-element");
+    if (passwordHost && !form.querySelector(".ulti-password-strength")) {
+      passwordHost.after(createStrengthMeter(password));
+    }
+
+    const repeatHost = repeat.closest("ak-form-element");
+    if (repeatHost && !form.querySelector(".ulti-password-match")) {
+      repeatHost.after(createMatchIndicator(password, repeat));
+    }
+  }
+
+  function scan() {
+    const executor = document.querySelector("ak-flow-executor");
+    if (!executor || flowSlug(executor) !== ENROLLMENT_SLUG) return false;
+
+    let found = false;
+    if (executor.shadowRoot) {
+      forEachDeep(executor.shadowRoot, (root) => {
+        root.querySelectorAll?.("form.pf-c-form")?.forEach((form) => {
+          found = true;
+          enhanceEnrollmentForm(form);
+        });
+      });
+    }
+    return found;
+  }
+
+  function observeExecutor(executor) {
+    if (!executor?.shadowRoot || executor.dataset.ultiObserved === "1") return;
+    executor.dataset.ultiObserved = "1";
+    new MutationObserver(() => scan()).observe(executor.shadowRoot, {
+      childList: true,
+      subtree: true,
+    });
+  }
+
+  function boot() {
+    let tries = 0;
+    const tick = () => {
+      tries += 1;
+      const executor = document.querySelector("ak-flow-executor");
+      observeExecutor(executor);
+      scan();
+      const enhanced = (() => {
+        const executor = document.querySelector("ak-flow-executor");
+        if (!executor?.shadowRoot) return null;
+        let match = null;
+        forEachDeep(executor.shadowRoot, (root) => {
+          match =
+            match ||
+            root.querySelector?.('form.pf-c-form[data-ulti-enhanced="1"]') ||
+            null;
+        });
+        return match;
+      })();
+      if (!enhanced && tries < 80) {
+        window.setTimeout(tick, 150);
+      }
+    };
+
+    tick();
+
+    new MutationObserver(() => {
+      observeExecutor(document.querySelector("ak-flow-executor"));
+      scan();
+    }).observe(document.body, { childList: true, subtree: true });
+  }
+
+  if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", boot);
+  } else {
+    boot();
+  }
+})();

deploy/docker-compose.yml

@@ -111,6 +111,8 @@ services:
     volumes:
       - ./authentik/blueprints:/blueprints/custom:ro
       - ./authentik/templates:/templates:ro
+      - ./authentik/branding/ulti-authentik.css:/web/dist/custom.css:ro
+      - ./authentik/branding/ulti-authentik.js:/web/dist/custom.js:ro
       - ./authentik/branding/ultisuite-logo-light.png:/web/dist/assets/branding/ultisuite-logo-light.png:ro
       - ./authentik/branding/ultisuite-logo-dark.png:/web/dist/assets/branding/ultisuite-logo-dark.png:ro
       - ./authentik/branding/ultisuite-favicon.png:/web/dist/assets/branding/ultisuite-favicon.png:ro

deploy/nginx/default.conf.template

@@ -271,7 +271,7 @@ server {
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
     }
-    location ^~ /api/v1/calendar/ {
+    location ^~ /api/v1/calendar {
         resolver 127.0.0.11 valid=10s ipv6=off;
         set $ultid_upstream ultid:8080;
         proxy_hide_header Access-Control-Allow-Origin;
@@ -589,6 +589,39 @@ server {
         proxy_set_header Connection $connection_upgrade;
     }
 
+    # Authentik brand CSS — bind-mount on authentik-server; must not sit behind CF 4h cache.
+    location = /auth/static/dist/custom.css {
+        resolver 127.0.0.11 valid=10s ipv6=off;
+        set $authentik_upstream authentik-server:9000;
+        proxy_pass http://$authentik_upstream;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_hide_header Cache-Control;
+        proxy_hide_header X-Frame-Options;
+        proxy_hide_header Content-Security-Policy;
+        add_header Cache-Control "no-cache, must-revalidate" always;
+        add_header Content-Security-Policy "frame-ancestors 'self' http://localhost:3004 http://127.0.0.1:3004" always;
+    }
+
+    location = /auth/static/dist/custom.js {
+        resolver 127.0.0.11 valid=10s ipv6=off;
+        set $authentik_upstream authentik-server:9000;
+        proxy_pass http://$authentik_upstream;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_hide_header Cache-Control;
+        proxy_hide_header X-Frame-Options;
+        proxy_hide_header Content-Security-Policy;
+        add_header Cache-Control "no-cache, must-revalidate" always;
+        add_header Content-Security-Policy "frame-ancestors 'self' http://localhost:3004 http://127.0.0.1:3004" always;
+    }
+
     location /auth/ {
         resolver 127.0.0.11 valid=10s ipv6=off;
         set $authentik_upstream authentik-server:9000;
@@ -600,11 +633,16 @@ server {
         proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection $connection_upgrade;
+        # sub_filter ne fonctionne pas sur les réponses gzip — désactiver la compression amont.
+        proxy_set_header Accept-Encoding "";
         proxy_read_timeout 86400;
         proxy_hide_header X-Frame-Options;
         proxy_hide_header Content-Security-Policy;
         # Permet l’embed du portail Authentik dans la suite (même host + dev Next :3004).
         add_header Content-Security-Policy "frame-ancestors 'self' http://localhost:3004 http://127.0.0.1:3004" always;
+        sub_filter_once off;
+        sub_filter_types text/html;
+        sub_filter '<link rel="stylesheet" type="text/css" href="/auth/static/dist/custom.css" data-inject>' '<link rel="stylesheet" type="text/css" href="/auth/static/dist/custom.css" data-inject><script src="/auth/static/dist/custom.js" defer></script>';
     }
 
     location /meet/ {
@@ -617,6 +655,23 @@ server {
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection $connection_upgrade;
+        proxy_read_timeout 86400;
+
+        # Jitsi serves root-relative assets (/css, /libs) — prefix for subpath /meet/
+        proxy_set_header Accept-Encoding "";
+        sub_filter_once off;
+        sub_filter_types text/html;
+        sub_filter '<base href="/"' '<base href="/meet/"';
+        sub_filter 'src="libs/' 'src="/meet/libs/';
+        sub_filter 'href="css/' 'href="/meet/css/';
+        sub_filter 'href="images/' 'href="/meet/images/';
+        sub_filter 'href="libs/' 'href="/meet/libs/';
+        sub_filter "'/libs/" "'/meet/libs/";
+        sub_filter '"/libs/' '"/meet/libs/';
+        sub_filter "'/css/" "'/meet/css/";
+        sub_filter '"/css/' '"/meet/css/';
     }
 
     # Public Nextcloud share links → UltiDrive viewer
@@ -1043,6 +1098,45 @@ server {
         proxy_set_header Connection $connection_upgrade;
     }
 
+    location ^~ /signup {
+        resolver 127.0.0.11 valid=10s ipv6=off;
+        set $mail_upstream ${MAIL_FRONTEND_UPSTREAM};
+        proxy_pass http://$mail_upstream;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection $connection_upgrade;
+    }
+
+    location ^~ /forgot-password {
+        resolver 127.0.0.11 valid=10s ipv6=off;
+        set $mail_upstream ${MAIL_FRONTEND_UPSTREAM};
+        proxy_pass http://$mail_upstream;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection $connection_upgrade;
+    }
+
+    location ^~ /reset-password {
+        resolver 127.0.0.11 valid=10s ipv6=off;
+        set $mail_upstream ${MAIL_FRONTEND_UPSTREAM};
+        proxy_pass http://$mail_upstream;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto ${FORWARDED_PROTO};
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection $connection_upgrade;
+    }
+
     location ^~ /chat {
         resolver 127.0.0.11 valid=10s ipv6=off;
         set $mail_upstream ${MAIL_FRONTEND_UPSTREAM};

internal/api/auth/complete.go

@@ -20,17 +20,12 @@ type flowCompleteResponse struct {
 }
 
 func (h *Handler) CompleteFlow(w http.ResponseWriter, r *http.Request) {
-	sessionID := readFlowSessionCookie(r)
+	returnTo := strings.TrimSpace(r.URL.Query().Get("returnTo"))
-	if sessionID == "" {
+	if returnTo == "" && r.Body != nil {
-		apiresponse.WriteError(w, r, http.StatusUnauthorized, "flow_session_missing", "flow session cookie required", nil)
-		return
-	}
-
 		var req flowCompleteRequest
-	if r.Body != nil {
 		_ = json.NewDecoder(r.Body).Decode(&req)
+		returnTo = strings.TrimSpace(req.ReturnTo)
 	}
-	returnTo := strings.TrimSpace(req.ReturnTo)
 	if returnTo == "" {
 		returnTo = "/mail/inbox"
 	}
@@ -39,8 +34,14 @@ func (h *Handler) CompleteFlow(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	sessionID := readFlowSessionCookie(r)
+	if sessionID == "" {
+		apiresponse.WriteError(w, r, http.StatusUnauthorized, "flow_session_missing", "flow session cookie required", nil)
+		return
+	}
+
 	slug := FlowAuthentication
-	cookies, err := h.flows.CompleteSession(r.Context(), sessionID, slug)
+	cookies, capturedCallback, err := h.flows.CompleteSessionOAuth(r.Context(), sessionID, slug)
 	if err != nil {
 		if errors.Is(err, authentik.ErrFlowSessionNotFound) {
 			clearFlowSessionCookie(w)
@@ -60,28 +61,111 @@ func (h *Handler) CompleteFlow(w http.ResponseWriter, r *http.Request) {
 	}
 
 	clearFlowSessionCookie(w)
-	setBrowserAuthentikCookies(w, cookies)
 
-	loginURL := buildLoginRedirectURL(h.appURL, returnTo)
+	if !authentik.SessionAuthenticated(cookies) {
-	apiresponse.WriteJSON(w, http.StatusOK, flowCompleteResponse{RedirectURL: loginURL})
+		msg := "authentik session not authenticated"
+		if r.Method == http.MethodGet {
+			base := suiteAuthAppOrigin(h.appURL)
+			http.Redirect(w, r, base+"/login?error="+url.QueryEscape("oidc_bridge_failed:"+msg), http.StatusFound)
+			return
+		}
+		apiresponse.WriteError(w, r, http.StatusBadGateway, "oidc_bridge_failed", msg, nil)
+		return
+	}
+
+	// The embedded flow already followed the OIDC authorize continuation within its authenticated
+	// session and captured the callback URL (carrying the authorization code). The browser holds the
+	// matching PKCE verifier + state cookies (set by the flow context endpoint), so we just redirect
+	// it to the Next.js callback which performs the token exchange.
+	var redirectURL string
+	if capturedCallback != "" {
+		redirectURL = capturedCallback
+	} else {
+		// Fallback: authorize server-side using the authenticated Authentik session.
+		callbackURL, pkceVerifier, state, bErr := h.oidc.callbackURL(r.Context(), cookies)
+		if bErr != nil {
+			if r.Method == http.MethodGet {
+				base := suiteAuthAppOrigin(h.appURL)
+				http.Redirect(w, r, base+"/login?error="+url.QueryEscape("oidc_bridge_failed:"+bErr.Error()), http.StatusFound)
+				return
+			}
+			apiresponse.WriteError(w, r, http.StatusBadGateway, "oidc_bridge_failed", bErr.Error(), nil)
+			return
+		}
+		setOAuthBridgeCookies(w, r, pkceVerifier, state, returnTo)
+		redirectURL = callbackURL
+	}
+
+	if r.Method == http.MethodGet {
+		http.Redirect(w, r, redirectURL, http.StatusFound)
+		return
+	}
+
+	apiresponse.WriteJSON(w, http.StatusOK, flowCompleteResponse{RedirectURL: redirectURL})
+}
+
+func setOAuthBridgeCookies(w http.ResponseWriter, r *http.Request, verifier, state, returnTo string) {
+	secure := requestIsHTTPS(r)
+	maxAge := 600
+	set := func(name, value string) {
+		http.SetCookie(w, &http.Cookie{
+			Name:     name,
+			Value:    value,
+			Path:     "/",
+			MaxAge:   maxAge,
+			HttpOnly: true,
+			SameSite: http.SameSiteLaxMode,
+			Secure:   secure,
+		})
+	}
+	set("ulti_pkce_verifier", verifier)
+	set("ulti_oauth_state", state)
+	set("ulti_auth_return", returnTo)
+}
+
+// suiteAuthAppOrigin is the suite root (auth routes live at /api/auth/*, not under /mail).
+func suiteAuthAppOrigin(appURL string) string {
+	base := strings.TrimRight(strings.TrimSpace(appURL), "/")
+	if strings.HasSuffix(base, "/mail") {
+		base = strings.TrimSuffix(base, "/mail")
+	}
+	if base == "" {
+		return "http://localhost:3004"
+	}
+	return base
 }
 
 func buildLoginRedirectURL(appURL, returnTo string) string {
-	base := strings.TrimRight(strings.TrimSpace(appURL), "/")
+	base := suiteAuthAppOrigin(appURL)
-	if base == "" {
-		base = "http://localhost:3004"
-	}
 	params := url.Values{}
 	params.Set("returnTo", returnTo)
+	params.Set("bridge", "1")
 	return base + "/api/auth/login?" + params.Encode()
 }
 
-func setBrowserAuthentikCookies(w http.ResponseWriter, stored []authentik.SerializedCookie) {
+func setBrowserAuthentikCookies(w http.ResponseWriter, r *http.Request, stored []authentik.SerializedCookie) {
+	secure := requestIsHTTPS(r)
 	for _, c := range authentik.BrowserAuthentikCookies(stored) {
+		if secure {
+			c.Secure = true
+		}
 		http.SetCookie(w, c)
 	}
 }
 
-func forwardFlowCookies(w http.ResponseWriter, stored []authentik.SerializedCookie) {
+func requestIsHTTPS(r *http.Request) bool {
-	setBrowserAuthentikCookies(w, stored)
+	if r.TLS != nil {
+		return true
+	}
+	if strings.EqualFold(r.Header.Get("X-Forwarded-Proto"), "https") {
+		return true
+	}
+	if strings.EqualFold(r.Header.Get("X-Forwarded-Ssl"), "on") {
+		return true
+	}
+	return false
+}
+
+func forwardFlowCookies(w http.ResponseWriter, r *http.Request, stored []authentik.SerializedCookie) {
+	setBrowserAuthentikCookies(w, r, stored)
 }

internal/api/auth/handlers.go

@@ -33,20 +33,26 @@ type Handler struct {
 	flows        *authentik.FlowSessionStore
 	limiter      *FlowRateLimiter
 	appURL       string
+	oidcClientID string
+	oidc         *oidcBridge
 }
 
-func NewHandler(baseURL, appURL string, rdb *redis.Client) *Handler {
+func NewHandler(baseURL, appURL, oidcIssuer, oidcClientID, oidcClientSecret string, rdb *redis.Client) *Handler {
 	return &Handler{
 		flows:        authentik.NewFlowSessionStore(baseURL, rdb),
 		limiter:      NewFlowRateLimiter(rdb),
 		appURL:       appURL,
+		oidcClientID: strings.TrimSpace(oidcClientID),
+		oidc:         newOIDCBridge(buildOIDCBridgeConfig(oidcIssuer, oidcClientID, oidcClientSecret, appURL, baseURL)),
 	}
 }
 
 func (h *Handler) Routes() chi.Router {
 	r := chi.NewRouter()
+	r.Get("/flows/authentication/context", h.PrepareOAuthFlowContext)
 	r.Post("/flows/{slug}/start", h.StartFlow)
 	r.Post("/flows/{slug}/respond", h.RespondFlow)
+	r.Get("/flows/complete", h.CompleteFlow)
 	r.Post("/flows/complete", h.CompleteFlow)
 	return r
 }
@@ -83,7 +89,7 @@ func (h *Handler) StartFlow(w http.ResponseWriter, r *http.Request) {
 	if !done {
 		setFlowSessionCookie(w, sessionID)
 		if cookies, err := h.flows.SessionCookies(r.Context(), sessionID); err == nil {
-			forwardFlowCookies(w, cookies)
+			forwardFlowCookies(w, r, cookies)
 		}
 	} else {
 		clearFlowSessionCookie(w)
@@ -144,14 +150,16 @@ func (h *Handler) RespondFlow(w http.ResponseWriter, r *http.Request) {
 			if denied {
 				clearFlowSessionCookie(w)
 				h.flows.Delete(r.Context(), sessionID)
+			} else if cookies, err := h.flows.SessionCookies(r.Context(), sessionID); err == nil {
+				// Push authenticated Authentik session to browser before OIDC bridge.
+				forwardFlowCookies(w, r, cookies)
 			}
-			// Successful auth: keep session cookie until /flows/complete.
 		} else {
 			clearFlowSessionCookie(w)
 			h.flows.Delete(r.Context(), sessionID)
 		}
 	} else if cookies, err := h.flows.SessionCookies(r.Context(), sessionID); err == nil {
-		forwardFlowCookies(w, cookies)
+		forwardFlowCookies(w, r, cookies)
 	}
 
 	writeFlowJSON(w, http.StatusOK, flowStartResponse{

internal/api/auth/handlers_test.go

@@ -37,7 +37,7 @@ func TestValidateFlowSlugRejected(t *testing.T) {
 
 func TestRespondFlowMissingCookie(t *testing.T) {
 	t.Parallel()
-	h := NewHandler("http://127.0.0.1:1", "http://localhost:3004", nil)
+	h := NewHandler("http://127.0.0.1:1", "http://localhost:3004", "", "", "", nil)
 	rec := httptest.NewRecorder()
 	req := httptest.NewRequest(http.MethodPost, "/flows/ulti-enrollment/respond", bytes.NewReader([]byte(`{"payload":{"component":"x"}}`)))
 	rctx := chi.NewRouteContext()
@@ -52,7 +52,33 @@ func TestRespondFlowMissingCookie(t *testing.T) {
 func TestBuildLoginRedirectURL(t *testing.T) {
 	t.Parallel()
 	got := buildLoginRedirectURL("http://localhost:3004", "/mail/inbox")
-	want := "http://localhost:3004/api/auth/login?returnTo=%2Fmail%2Finbox"
+	want := "http://localhost:3004/api/auth/login?bridge=1&returnTo=%2Fmail%2Finbox"
+	if got != want {
+		t.Fatalf("got %q want %q", got, want)
+	}
+}
+
+func TestBuildOIDCBridgeConfig(t *testing.T) {
+	t.Parallel()
+	cfg := buildOIDCBridgeConfig(
+		"http://nginx/auth/application/o/ulti/",
+		"ulti-backend",
+		"changeme",
+		"https://dev.ultispace.fr/mail",
+		"http://authentik-server:9000",
+	)
+	if cfg.redirectURI != "https://dev.ultispace.fr/api/auth/callback" {
+		t.Fatalf("redirectURI = %q", cfg.redirectURI)
+	}
+	if cfg.authorizeURL != "http://authentik-server:9000/auth/application/o/authorize/" {
+		t.Fatalf("authorizeURL = %q", cfg.authorizeURL)
+	}
+}
+
+func TestBuildLoginRedirectURLStripsMailPrefix(t *testing.T) {
+	t.Parallel()
+	got := buildLoginRedirectURL("https://dev.ultispace.fr/mail", "/mail/inbox")
+	want := "https://dev.ultispace.fr/api/auth/login?bridge=1&returnTo=%2Fmail%2Finbox"
 	if got != want {
 		t.Fatalf("got %q want %q", got, want)
 	}

internal/api/auth/oauth_context.go

@@ -0,0 +1,76 @@
+package authapi
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/ultisuite/ulti-backend/internal/api/apiresponse"
+)
+
+type oauthFlowContextResponse struct {
+	FlowQuery string `json:"flowQuery"`
+}
+
+// PrepareOAuthFlowContext returns the Authentik flow executor query string that binds
+// embedded authentication to the pending OIDC authorize request (see Authentik flow-executor docs).
+func (h *Handler) PrepareOAuthFlowContext(w http.ResponseWriter, r *http.Request) {
+	if h.oidcClientID == "" {
+		apiresponse.WriteError(w, r, http.StatusServiceUnavailable, "oidc_not_configured", "OIDC client id not configured", nil)
+		return
+	}
+
+	returnTo := strings.TrimSpace(r.URL.Query().Get("returnTo"))
+	if returnTo == "" {
+		returnTo = "/mail/inbox"
+	}
+	if !strings.HasPrefix(returnTo, "/") || strings.HasPrefix(returnTo, "//") {
+		apiresponse.WriteError(w, r, http.StatusBadRequest, "invalid_return_to", "returnTo must be a relative path", nil)
+		return
+	}
+
+	verifier, challenge, err := newPKCEPair()
+	if err != nil {
+		apiresponse.WriteError(w, r, http.StatusInternalServerError, "pkce_failed", err.Error(), nil)
+		return
+	}
+	state, err := randomOAuthState()
+	if err != nil {
+		apiresponse.WriteError(w, r, http.StatusInternalServerError, "state_failed", err.Error(), nil)
+		return
+	}
+	setOAuthBridgeCookies(w, r, verifier, state, returnTo)
+
+	flowQuery := buildOAuthFlowQuery(h.appURL, h.oidcClientID, state, challenge)
+	apiresponse.WriteJSON(w, http.StatusOK, oauthFlowContextResponse{FlowQuery: flowQuery})
+}
+
+func buildOAuthFlowQuery(appURL, clientID, state, codeChallenge string) string {
+	base := suiteAuthAppOrigin(appURL)
+	oauthParams := url.Values{}
+	oauthParams.Set("client_id", clientID)
+	oauthParams.Set("redirect_uri", base+"/api/auth/callback")
+	oauthParams.Set("response_type", "code")
+	oauthParams.Set("scope", "openid profile email offline_access")
+	oauthParams.Set("state", state)
+	oauthParams.Set("code_challenge", codeChallenge)
+	oauthParams.Set("code_challenge_method", "S256")
+
+	authorizePath := "/auth/application/o/authorize/?" + oauthParams.Encode()
+	flowParams := url.Values{}
+	flowParams.Set("next", authorizePath)
+	return flowParams.Encode()
+}
+
+func buildOAuthAuthorizeURL(appURL, clientID, state, codeChallenge string) string {
+	base := suiteAuthAppOrigin(appURL)
+	oauthParams := url.Values{}
+	oauthParams.Set("client_id", clientID)
+	oauthParams.Set("redirect_uri", base+"/api/auth/callback")
+	oauthParams.Set("response_type", "code")
+	oauthParams.Set("scope", "openid profile email offline_access")
+	oauthParams.Set("state", state)
+	oauthParams.Set("code_challenge", codeChallenge)
+	oauthParams.Set("code_challenge_method", "S256")
+	return base + "/auth/application/o/authorize/?" + oauthParams.Encode()
+}

internal/api/auth/oauth_context_test.go

@@ -0,0 +1,26 @@
+package authapi
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildOAuthFlowQuery(t *testing.T) {
+	t.Parallel()
+	q := buildOAuthFlowQuery(
+		"https://dev.ultispace.fr/mail",
+		"ulti-backend",
+		"state123",
+		"challenge456",
+	)
+	for _, part := range []string{
+		"next=",
+		"ulti-backend",
+		"state123",
+		"challenge456",
+	} {
+		if !strings.Contains(q, part) {
+			t.Fatalf("flow query missing %q: %q", part, q)
+		}
+	}
+}

internal/api/auth/oidc_bridge.go

@@ -0,0 +1,306 @@
+package authapi
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/http/cookiejar"
+	"net/url"
+	"strings"
+
+	"github.com/ultisuite/ulti-backend/internal/authentik"
+)
+
+type oidcBridgeConfig struct {
+	clientID      string
+	clientSecret  string
+	redirectURI   string
+	authorizeURL  string
+	authentikBase string
+}
+
+type oidcBridge struct {
+	cfg oidcBridgeConfig
+}
+
+func newOIDCBridge(cfg oidcBridgeConfig) *oidcBridge {
+	return &oidcBridge{cfg: cfg}
+}
+
+func buildOIDCBridgeConfig(_issuer, clientID, clientSecret, appURL, authentikAPIURL string) oidcBridgeConfig {
+	base := suiteAuthAppOrigin(appURL)
+	redirectURI := base + "/api/auth/callback"
+	authentikBase := authentik.APIBaseURL(authentikAPIURL)
+	return oidcBridgeConfig{
+		clientID:      strings.TrimSpace(clientID),
+		clientSecret:  strings.TrimSpace(clientSecret),
+		redirectURI:   redirectURI,
+		authorizeURL:  strings.TrimSuffix(authentikBase, "/") + "/application/o/authorize/",
+		authentikBase: authentikBase,
+	}
+}
+
+// callbackURL performs a server-side OIDC authorize using the Authentik session from the embedded flow.
+func (b *oidcBridge) callbackURL(ctx context.Context, cookies []authentik.SerializedCookie) (callbackURL, pkceVerifier, state string, err error) {
+	if b == nil || b.cfg.clientID == "" || b.cfg.clientSecret == "" || b.cfg.redirectURI == "" {
+		return "", "", "", fmt.Errorf("oidc bridge not configured")
+	}
+	if !authentik.SessionAuthenticated(cookies) {
+		return "", "", "", fmt.Errorf("authentik session not authenticated")
+	}
+
+	verifier, challenge, err := newPKCEPair()
+	if err != nil {
+		return "", "", "", err
+	}
+	state, err = randomOAuthState()
+	if err != nil {
+		return "", "", "", err
+	}
+
+	jar, err := cookiejar.New(nil)
+	if err != nil {
+		return "", "", "", err
+	}
+	cookieURL, err := url.Parse(strings.TrimSuffix(b.cfg.authentikBase, "/") + "/")
+	if err != nil {
+		return "", "", "", err
+	}
+	jar.SetCookies(cookieURL, authentik.BrowserAuthentikCookies(cookies))
+
+	var captured *url.URL
+	client := &http.Client{
+		Jar: jar,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			slog.Info("oidc bridge redirect", "to", redactQuery(req.URL))
+			if strings.HasPrefix(req.URL.String(), b.cfg.redirectURI) {
+				captured = req.URL
+				return http.ErrUseLastResponse
+			}
+			if len(via) >= 15 {
+				return fmt.Errorf("too many oauth redirects")
+			}
+			return nil
+		},
+	}
+
+	params := url.Values{}
+	params.Set("client_id", b.cfg.clientID)
+	params.Set("redirect_uri", b.cfg.redirectURI)
+	params.Set("response_type", "code")
+	params.Set("scope", "openid profile email offline_access")
+	params.Set("state", state)
+	params.Set("code_challenge", challenge)
+	params.Set("code_challenge_method", "S256")
+
+	authURL := b.cfg.authorizeURL + "?" + params.Encode()
+	captured, err = b.runAuthorize(ctx, client, jar, authURL, captured)
+	if err != nil {
+		return "", "", "", err
+	}
+	if captured == nil {
+		return "", "", "", fmt.Errorf("oidc authorize did not return an authorization code")
+	}
+	if captured.Query().Get("code") == "" {
+		return "", "", "", fmt.Errorf("oidc authorize missing code (session may be unauthenticated)")
+	}
+	if captured.Query().Get("state") != state {
+		return "", "", "", fmt.Errorf("oidc authorize state mismatch")
+	}
+
+	return captured.String(), verifier, state, nil
+}
+
+// runAuthorize performs the authorize request and, if Authentik routes through the
+// authorization flow (implicit consent), drives that flow via the executor API to obtain the code.
+func (b *oidcBridge) runAuthorize(ctx context.Context, client *http.Client, jar http.CookieJar, authURL string, captured *url.URL) (*url.URL, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, authURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/json")
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	finalURL := resp.Request.URL
+	loc := resp.Header.Get("Location")
+	status := resp.StatusCode
+	io.Copy(io.Discard, io.LimitReader(resp.Body, 1<<16))
+	resp.Body.Close()
+
+	if captured != nil {
+		return captured, nil
+	}
+	if strings.HasPrefix(loc, b.cfg.redirectURI) {
+		return url.Parse(loc)
+	}
+
+	// Landed on the authorization flow UI: drive it via the flow executor (implicit consent).
+	if slug := authorizationFlowSlug(finalURL); slug != "" {
+		slog.Info("oidc bridge driving authorization flow", "slug", slug)
+		code, err := b.driveAuthorizationFlow(ctx, client, slug, finalURL)
+		if err != nil {
+			return nil, err
+		}
+		if code != nil {
+			return code, nil
+		}
+	}
+
+	slog.Warn("oidc bridge no code", "status", status, "final", redactQuery(finalURL), "location", loc)
+	if loc != "" {
+		return nil, fmt.Errorf("oidc authorize unexpected redirect to %s (status %d)", loc, status)
+	}
+	return nil, fmt.Errorf("oidc authorize did not return an authorization code (status %d)", status)
+}
+
+// driveAuthorizationFlow runs the provider authorization flow executor and follows its
+// terminal redirect, returning the captured callback URL with the authorization code.
+func (b *oidcBridge) driveAuthorizationFlow(ctx context.Context, client *http.Client, slug string, flowURL *url.URL) (*url.URL, error) {
+	next := flowURL.Query().Get("next")
+	execURL := strings.TrimSuffix(b.cfg.authentikBase, "/") + "/api/v3/flows/executor/" + slug + "/"
+	if next != "" {
+		execURL += "?query=" + url.QueryEscape(strings.TrimPrefix(next, "/auth"))
+	}
+
+	for i := 0; i < 6; i++ {
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, execURL, nil)
+		if err != nil {
+			return nil, err
+		}
+		req.Header.Set("Accept", "application/json")
+		resp, err := client.Do(req)
+		if err != nil {
+			return nil, err
+		}
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<18))
+		resp.Body.Close()
+
+		var challenge map[string]any
+		_ = json.Unmarshal(body, &challenge)
+		comp, _ := challenge["component"].(string)
+		slog.Info("oidc bridge authz flow stage", "component", comp)
+
+		switch comp {
+		case "xak-flow-redirect":
+			to, _ := challenge["to"].(string)
+			if strings.HasPrefix(to, b.cfg.redirectURI) {
+				return url.Parse(to)
+			}
+			if u := b.followToCallback(ctx, client, to); u != nil {
+				return u, nil
+			}
+			return nil, fmt.Errorf("authorization flow redirected to %s (no code)", to)
+		case "ak-stage-consent":
+			token, _ := challenge["token"].(string)
+			postReq, err := postAuthorizeConsent(ctx, execURL, token, client)
+			if err != nil {
+				return nil, err
+			}
+			if postReq != nil {
+				return postReq, nil
+			}
+		default:
+			return nil, fmt.Errorf("authorization flow stuck at stage %q", comp)
+		}
+	}
+	return nil, fmt.Errorf("authorization flow did not complete")
+}
+
+func postAuthorizeConsent(ctx context.Context, execURL, token string, client *http.Client) (*url.URL, error) {
+	payload := map[string]any{"component": "ak-stage-consent"}
+	if token != "" {
+		payload["token"] = token
+	}
+	raw, _ := json.Marshal(payload)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, execURL, strings.NewReader(string(raw)))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Referer", execURL)
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<18))
+	resp.Body.Close()
+	var challenge map[string]any
+	_ = json.Unmarshal(body, &challenge)
+	if to, _ := challenge["to"].(string); to != "" {
+		return url.Parse(to)
+	}
+	return nil, nil
+}
+
+func (b *oidcBridge) followToCallback(ctx context.Context, client *http.Client, to string) *url.URL {
+	if to == "" {
+		return nil
+	}
+	target := to
+	if strings.HasPrefix(to, "/") {
+		target = strings.TrimSuffix(b.cfg.authentikBase, "/") + to
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, target, nil)
+	if err != nil {
+		return nil
+	}
+	var captured *url.URL
+	client.CheckRedirect = func(r *http.Request, via []*http.Request) error {
+		if strings.HasPrefix(r.URL.String(), b.cfg.redirectURI) {
+			captured = r.URL
+			return http.ErrUseLastResponse
+		}
+		if len(via) >= 10 {
+			return fmt.Errorf("too many redirects")
+		}
+		return nil
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil
+	}
+	loc := resp.Header.Get("Location")
+	io.Copy(io.Discard, io.LimitReader(resp.Body, 1<<16))
+	resp.Body.Close()
+	if captured != nil {
+		return captured
+	}
+	if strings.HasPrefix(loc, b.cfg.redirectURI) {
+		u, _ := url.Parse(loc)
+		return u
+	}
+	return nil
+}
+
+func authorizationFlowSlug(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	// Matches /auth/if/flow/<slug>/ and /if/flow/<slug>/
+	parts := strings.Split(strings.Trim(u.Path, "/"), "/")
+	for i := 0; i+1 < len(parts); i++ {
+		if parts[i] == "flow" && i >= 1 && parts[i-1] == "if" {
+			slug := parts[i+1]
+			if strings.Contains(slug, "authentication") {
+				return "" // login flow → not authenticated, don't loop
+			}
+			return slug
+		}
+	}
+	return ""
+}
+
+func redactQuery(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	c := *u
+	c.RawQuery = ""
+	return c.String()
+}

internal/api/auth/pkce.go

@@ -0,0 +1,31 @@
+package authapi
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+)
+
+func newPKCEPair() (verifier, challenge string, err error) {
+	b := make([]byte, 32)
+	if _, err := rand.Read(b); err != nil {
+		return "", "", err
+	}
+	verifier = base64.RawURLEncoding.EncodeToString(b)
+	sum := sha256.Sum256([]byte(verifier))
+	challenge = base64.RawURLEncoding.EncodeToString(sum[:])
+	return verifier, challenge, nil
+}
+
+func pkceChallengeFromVerifier(verifier string) string {
+	sum := sha256.Sum256([]byte(verifier))
+	return base64.RawURLEncoding.EncodeToString(sum[:])
+}
+
+func randomOAuthState() (string, error) {
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(b), nil
+}

internal/api/middleware/forwarded.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+)
+
+// ForwardedHeaders sets r.URL.Scheme and r.URL.Host from reverse-proxy headers so
+// chi RedirectSlashes and other absolute redirects use https behind Cloudflare/nginx.
+func ForwardedHeaders(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if proto := strings.TrimSpace(r.Header.Get("X-Forwarded-Proto")); proto != "" {
+			if i := strings.IndexByte(proto, ','); i >= 0 {
+				proto = strings.TrimSpace(proto[:i])
+			}
+			r.URL.Scheme = proto
+		}
+		if host := strings.TrimSpace(r.Header.Get("X-Forwarded-Host")); host != "" {
+			if i := strings.IndexByte(host, ','); i >= 0 {
+				host = strings.TrimSpace(host[:i])
+			}
+			r.URL.Host = host
+		} else if r.Host != "" {
+			r.URL.Host = r.Host
+		}
+		next.ServeHTTP(w, r)
+	})
+}

internal/api/middleware/forwarded_test.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestForwardedHeaders(t *testing.T) {
+	var gotScheme, gotHost string
+	handler := ForwardedHeaders(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotScheme = r.URL.Scheme
+		gotHost = r.URL.Host
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "http://ultid:8080/api/v1/calendar", nil)
+	req.Header.Set("X-Forwarded-Proto", "https")
+	req.Header.Set("X-Forwarded-Host", "dev.ultispace.fr")
+	req.Host = "dev.ultispace.fr"
+	handler.ServeHTTP(httptest.NewRecorder(), req)
+
+	if gotScheme != "https" {
+		t.Fatalf("scheme = %q, want https", gotScheme)
+	}
+	if gotHost != "dev.ultispace.fr" {
+		t.Fatalf("host = %q, want dev.ultispace.fr", gotHost)
+	}
+}

internal/authentik/flow_executor.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
@@ -50,26 +51,44 @@ func NewFlowExecutor(baseURL, slug string) (*FlowExecutor, error) {
 func (fe *FlowExecutor) executorURL(query string) string {
 	u := fmt.Sprintf("%s/api/v3/flows/executor/%s/", fe.baseURL, fe.slug)
 	if query != "" {
-		return u + "?" + query
+		// Authentik's flow executor reads the original frontend querystring from a `query`
+		// parameter (e.g. ?query=next%3D...). Passing the params directly is ignored.
+		return u + "?query=" + url.QueryEscape(query)
 	}
 	return u
 }
 
 // GetChallenge starts or resumes a flow and returns the pending challenge.
 func (fe *FlowExecutor) GetChallenge(ctx context.Context, query string) (FlowChallenge, error) {
-	if err := fe.warmSession(ctx); err != nil {
+	// Establish the flow plan via the executor GET with the query string so the OAuth `next`
-		return nil, err
+	// continuation is captured in the plan. Calling execute/ first would create a plan without
-	}
+	// `next`, and the executor GET would then reuse that plan and ignore our continuation.
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fe.executorURL(query), nil)
 	if err != nil {
 		return nil, err
 	}
 	req.Header.Set("Accept", "application/json")
-	return fe.doChallenge(req)
+	challenge, err := fe.doChallenge(req)
+	if err == nil {
+		return challenge, nil
+	}
+	// Fallback: some Authentik configs require a warmed session cookie before the executor GET.
+	if warmErr := fe.warmSession(ctx, query); warmErr != nil {
+		return nil, err
+	}
+	req2, err2 := http.NewRequestWithContext(ctx, http.MethodGet, fe.executorURL(query), nil)
+	if err2 != nil {
+		return nil, err2
+	}
+	req2.Header.Set("Accept", "application/json")
+	return fe.doChallenge(req2)
 }
 
-func (fe *FlowExecutor) warmSession(ctx context.Context) error {
+func (fe *FlowExecutor) warmSession(ctx context.Context, query string) error {
 	u := fmt.Sprintf("%s/api/v3/flows/instances/%s/execute/", fe.baseURL, fe.slug)
+	if query != "" {
+		u += "?query=" + url.QueryEscape(query)
+	}
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
 	if err != nil {
 		return err
@@ -106,6 +125,236 @@ func (fe *FlowExecutor) PostResponse(ctx context.Context, query string, payload
 	return fe.doChallenge(req)
 }
 
+// FollowFlowRedirect loads the flow completion URL so Authentik can bind an authenticated session.
+func (fe *FlowExecutor) FollowFlowRedirect(ctx context.Context, target string) error {
+	target = strings.TrimSpace(target)
+	if target == "" {
+		return nil
+	}
+	resolved, err := fe.resolveRedirectURL(target)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, resolved, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Accept", "application/json")
+	resp, err := fe.client.Do(req)
+	if err != nil {
+		return err
+	}
+	io.Copy(io.Discard, resp.Body)
+	resp.Body.Close()
+	if resp.StatusCode >= 500 {
+		return fmt.Errorf("follow flow redirect: %d", resp.StatusCode)
+	}
+	return nil
+}
+
+// CaptureOAuthCallback follows the post-authentication authorize redirect (`to`) within the
+// executor's live, authenticated jar and returns the external callback URL carrying the
+// authorization code. This mirrors what a browser does after login and is the supported way to
+// bridge an embedded (API-driven) Authentik session to an OIDC authorization code.
+func (fe *FlowExecutor) CaptureOAuthCallback(ctx context.Context, to string) (string, error) {
+	toURL, err := url.Parse(to)
+	if err != nil {
+		return "", fmt.Errorf("parse authorize redirect: %w", err)
+	}
+	redirectURI := toURL.Query().Get("redirect_uri")
+	if redirectURI == "" {
+		return "", fmt.Errorf("authorize redirect missing redirect_uri")
+	}
+	resolved, err := fe.resolveRedirectURL(to)
+	if err != nil {
+		return "", err
+	}
+
+	var captured *url.URL
+	client := &http.Client{
+		Jar:     fe.client.Jar,
+		Timeout: fe.client.Timeout,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			if strings.HasPrefix(req.URL.String(), redirectURI) {
+				captured = req.URL
+				return http.ErrUseLastResponse
+			}
+			if len(via) >= 15 {
+				return fmt.Errorf("too many authorize redirects")
+			}
+			return nil
+		},
+	}
+
+	current := resolved
+	for i := 0; i < 6; i++ {
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, current, nil)
+		if err != nil {
+			return "", err
+		}
+		req.Header.Set("Accept", "text/html,application/xhtml+xml")
+		resp, err := client.Do(req)
+		if err != nil {
+			return "", err
+		}
+		loc := resp.Header.Get("Location")
+		finalURL := resp.Request.URL
+		io.Copy(io.Discard, io.LimitReader(resp.Body, 1<<16))
+		resp.Body.Close()
+
+		if captured != nil {
+			return captured.String(), nil
+		}
+		if strings.HasPrefix(loc, redirectURI) {
+			return loc, nil
+		}
+
+		// Authorize routed through a flow (e.g. implicit-consent authorization flow). Drive it
+		// via the executor API to obtain the terminal redirect with the code.
+		slug := flowSlugFromURL(finalURL)
+		if slug == "" {
+			return "", fmt.Errorf("authorize did not yield a callback (landed on %s)", redactURL(finalURL))
+		}
+		callback, next, err := fe.driveFlowToRedirect(ctx, client, slug, finalURL, redirectURI)
+		if err != nil {
+			return "", err
+		}
+		if callback != "" {
+			return callback, nil
+		}
+		if next == "" {
+			return "", fmt.Errorf("authorization flow %q did not complete", slug)
+		}
+		current = next
+	}
+	return "", fmt.Errorf("authorize redirect chain did not resolve to a callback")
+}
+
+// driveFlowToRedirect runs a flow executor (used for the implicit-consent authorization flow)
+// until it produces a terminal redirect. Returns either a captured callback URL, or a next URL
+// to continue following.
+func (fe *FlowExecutor) driveFlowToRedirect(ctx context.Context, client *http.Client, slug string, flowURL *url.URL, redirectURI string) (callback string, next string, err error) {
+	q := flowURL.Query().Get("query")
+	if q == "" {
+		q = flowURL.RawQuery
+	}
+	execURL := fmt.Sprintf("%s/api/v3/flows/executor/%s/", fe.baseURL, slug)
+	if q != "" {
+		execURL += "?query=" + url.QueryEscape(q)
+	}
+
+	for i := 0; i < 6; i++ {
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, execURL, nil)
+		if err != nil {
+			return "", "", err
+		}
+		req.Header.Set("Accept", "application/json")
+		resp, err := client.Do(req)
+		if err != nil {
+			return "", "", err
+		}
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<18))
+		resp.Body.Close()
+		var ch FlowChallenge
+		_ = json.Unmarshal(body, &ch)
+		comp := FlowComponent(ch)
+		slog.Info("capture authz flow stage", "slug", slug, "component", comp)
+
+		switch comp {
+		case "xak-flow-redirect":
+			toStr, _ := ch["to"].(string)
+			if strings.HasPrefix(toStr, redirectURI) {
+				return toStr, "", nil
+			}
+			resolved, rErr := fe.resolveRedirectURL(toStr)
+			if rErr != nil {
+				return "", "", rErr
+			}
+			return "", resolved, nil
+		case "ak-stage-consent":
+			payload := map[string]any{"component": "ak-stage-consent"}
+			pr, pErr := fe.postFlowStage(ctx, client, execURL, payload)
+			if pErr != nil {
+				return "", "", pErr
+			}
+			if to, _ := pr["to"].(string); to != "" {
+				if strings.HasPrefix(to, redirectURI) {
+					return to, "", nil
+				}
+				resolved, _ := fe.resolveRedirectURL(to)
+				return "", resolved, nil
+			}
+		default:
+			return "", "", fmt.Errorf("authorization flow %q stuck at %q", slug, comp)
+		}
+	}
+	return "", "", fmt.Errorf("authorization flow %q did not complete", slug)
+}
+
+func (fe *FlowExecutor) postFlowStage(ctx context.Context, client *http.Client, execURL string, payload map[string]any) (FlowChallenge, error) {
+	raw, _ := json.Marshal(payload)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, execURL, bytes.NewReader(raw))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Referer", execURL)
+	if csrf := fe.csrfToken(); csrf != "" {
+		req.Header.Set("X-authentik-CSRF", csrf)
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<18))
+	var ch FlowChallenge
+	_ = json.Unmarshal(body, &ch)
+	return ch, nil
+}
+
+func flowSlugFromURL(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	parts := strings.Split(strings.Trim(u.Path, "/"), "/")
+	for i := 0; i+1 < len(parts); i++ {
+		if parts[i] == "flow" && i >= 1 && parts[i-1] == "if" {
+			slug := parts[i+1]
+			if strings.Contains(slug, "authentication") {
+				return ""
+			}
+			return slug
+		}
+	}
+	return ""
+}
+
+func redactURL(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	c := *u
+	c.RawQuery = ""
+	return c.String()
+}
+
+func (fe *FlowExecutor) resolveRedirectURL(target string) (string, error) {
+	if strings.HasPrefix(target, "http://") || strings.HasPrefix(target, "https://") {
+		return target, nil
+	}
+	base, err := url.Parse(fe.baseURL)
+	if err != nil {
+		return "", err
+	}
+	rel, err := url.Parse(target)
+	if err != nil {
+		return "", err
+	}
+	return base.ResolveReference(rel).String(), nil
+}
+
 func (fe *FlowExecutor) cookieURL() *url.URL {
 	u, err := url.Parse(fe.baseURL)
 	if err != nil || u.Host == "" {

internal/authentik/flow_executor_redirect_test.go

@@ -0,0 +1,38 @@
+package authentik
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestFollowFlowRedirectUpdatesJar(t *testing.T) {
+	t.Parallel()
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.SetCookie(w, &http.Cookie{
+			Name:  "authentik_session",
+			Value: "authenticated-session",
+			Path:  "/auth/",
+		})
+		w.WriteHeader(http.StatusOK)
+	}))
+	t.Cleanup(srv.Close)
+
+	fe, err := NewFlowExecutor(srv.URL+"/auth", "default-authentication-flow")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := fe.FollowFlowRedirect(context.Background(), "/auth/done"); err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	for _, c := range fe.client.Jar.Cookies(fe.cookieURL()) {
+		if c.Name == "authentik_session" && c.Value == "authenticated-session" {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatal("expected session cookie after follow redirect")
+	}
+}

internal/authentik/flow_session_store.go

@@ -6,6 +6,9 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"log/slog"
+	"strings"
 	"sync"
 	"time"
 
@@ -22,6 +25,7 @@ type storedFlowSession struct {
 	Cookies       []SerializedCookie `json:"cookies"`
 	CreatedAt     time.Time          `json:"createdAt"`
 	Completed     bool               `json:"completed,omitempty"`
+	OAuthCallback string             `json:"oauthCallback,omitempty"`
 }
 
 type flowSessionEntry struct {
@@ -29,6 +33,7 @@ type flowSessionEntry struct {
 	cookies       []SerializedCookie
 	createdAt     time.Time
 	completed     bool
+	oauthCallback string
 }
 
 // FlowSessionStore keeps Authentik flow executor sessions (memory + optional KeyDB).
@@ -96,35 +101,132 @@ func (s *FlowSessionStore) Respond(ctx context.Context, sessionID, slug, query s
 		return nil, err
 	}
 	entry.cookies = executor.ExportCookies()
-	done, denied := FlowDone(challenge)
+	challenge, err = s.advanceHeadlessStages(ctx, executor, query, challenge)
-	if done && !denied {
+	if err != nil {
+		return nil, err
+	}
+	entry.cookies = executor.ExportCookies()
+
+	if SessionAuthenticated(entry.cookies) {
 		entry.completed = true
+		// If the flow's terminal redirect is an OIDC authorize continuation, follow it within the
+		// live authenticated jar to capture the authorization code (the only reliable way to bridge
+		// an API-driven session to OIDC; replaying the session cookie elsewhere is rejected).
+		if to, ok := challenge["to"].(string); ok && isOAuthAuthorizeRedirect(to) {
+			callback, capErr := executor.CaptureOAuthCallback(ctx, to)
+			if capErr != nil {
+				slog.Warn("capture oauth callback failed", "err", capErr.Error())
+			} else {
+				entry.oauthCallback = callback
+				slog.Info("captured oauth callback", "ok", callback != "")
+			}
+		}
 		if err := s.save(ctx, sessionID, entry); err != nil {
 			return nil, err
 		}
+		if FlowComponent(challenge) != "xak-flow-redirect" {
+			challenge = FlowChallenge{"component": "xak-flow-redirect"}
+		}
 		return challenge, nil
 	}
+
+	done, denied := FlowDone(challenge)
+	if done && !denied {
+		return nil, fmt.Errorf("authentik flow finished without authenticated session")
+	}
 	if err := s.save(ctx, sessionID, entry); err != nil {
 		return nil, err
 	}
 	return challenge, nil
 }
 
-// CompleteSession returns cookies from a completed flow and removes the session.
+func (s *FlowSessionStore) advanceHeadlessStages(ctx context.Context, executor *FlowExecutor, query string, challenge FlowChallenge) (FlowChallenge, error) {
-func (s *FlowSessionStore) CompleteSession(ctx context.Context, sessionID, slug string) ([]SerializedCookie, error) {
+	const maxSteps = 8
-	entry, err := s.load(ctx, sessionID)
+	for step := 0; step < maxSteps; step++ {
+		if SessionAuthenticated(executor.ExportCookies()) {
+			return challenge, nil
+		}
+		if _, denied := FlowDone(challenge); denied {
+			return challenge, nil
+		}
+
+		switch FlowComponent(challenge) {
+		case "ak-stage-user-login":
+			var err error
+			challenge, err = executor.PostResponse(ctx, query, map[string]any{"component": "ak-stage-user-login"})
 			if err != nil {
 				return nil, err
 			}
+		case "xak-flow-redirect":
+			// Resume pending stages before following terminal redirects (/auth/ resets session).
+			next, err := executor.GetChallenge(ctx, query)
+			if err != nil {
+				return nil, err
+			}
+			if comp := FlowComponent(next); comp != "" && comp != "xak-flow-redirect" {
+				challenge = next
+				continue
+			}
+			if to, ok := challenge["to"].(string); ok && isTerminalFlowRedirect(to) {
+				loginChallenge, loginErr := executor.PostResponse(ctx, query, map[string]any{"component": "ak-stage-user-login"})
+				if loginErr == nil {
+					challenge = loginChallenge
+					continue
+				}
+				return challenge, nil
+			}
+			if to, ok := challenge["to"].(string); ok && strings.TrimSpace(to) != "" {
+				if err := executor.FollowFlowRedirect(ctx, to); err != nil {
+					return nil, err
+				}
+			}
+			next, err = executor.GetChallenge(ctx, query)
+			if err != nil {
+				return nil, err
+			}
+			challenge = next
+		default:
+			return challenge, nil
+		}
+	}
+	return challenge, nil
+}
+
+func isOAuthAuthorizeRedirect(to string) bool {
+	return strings.Contains(to, "/application/o/authorize")
+}
+
+func isTerminalFlowRedirect(to string) bool {
+	to = strings.TrimSpace(to)
+	if to == "" || to == "/auth/" || to == "/auth" {
+		return true
+	}
+	return strings.HasSuffix(strings.TrimSuffix(to, "/"), "/auth")
+}
+
+// CompleteSession returns cookies from a completed flow and removes the session.
+func (s *FlowSessionStore) CompleteSession(ctx context.Context, sessionID, slug string) ([]SerializedCookie, error) {
+	cookies, _, err := s.CompleteSessionOAuth(ctx, sessionID, slug)
+	return cookies, err
+}
+
+// CompleteSessionOAuth returns the completed flow's cookies plus any captured OIDC callback URL
+// (carrying the authorization code) and removes the session.
+func (s *FlowSessionStore) CompleteSessionOAuth(ctx context.Context, sessionID, slug string) ([]SerializedCookie, string, error) {
+	entry, err := s.load(ctx, sessionID)
+	if err != nil {
+		return nil, "", err
+	}
 	if entry.slug != slug {
-		return nil, ErrFlowSessionSlugMismatch
+		return nil, "", ErrFlowSessionSlugMismatch
 	}
 	if !entry.completed {
-		return nil, ErrFlowSessionNotCompleted
+		return nil, "", ErrFlowSessionNotCompleted
 	}
 	cookies := entry.cookies
+	callback := entry.oauthCallback
 	s.delete(ctx, sessionID)
-	return cookies, nil
+	return cookies, callback, nil
 }
 
 // SessionCookies returns current Authentik cookies for an active session.
@@ -152,6 +254,7 @@ func (s *FlowSessionStore) save(ctx context.Context, sessionID string, entry *fl
 		Cookies:       entry.cookies,
 		CreatedAt:     entry.createdAt,
 		Completed:     entry.completed,
+		OAuthCallback: entry.oauthCallback,
 	}
 	raw, err := json.Marshal(stored)
 	if err != nil {
@@ -182,6 +285,7 @@ func (s *FlowSessionStore) load(ctx context.Context, sessionID string) (*flowSes
 			cookies:       stored.Cookies,
 			createdAt:     stored.CreatedAt,
 			completed:     stored.Completed,
+			oauthCallback: stored.OAuthCallback,
 		}
 		s.mu.Lock()
 		s.items[sessionID] = entry

internal/authentik/flow_session_store_test.go

@@ -0,0 +1,21 @@
+package authentik
+
+import "testing"
+
+func TestIsTerminalFlowRedirect(t *testing.T) {
+	t.Parallel()
+	for _, tc := range []struct {
+		to   string
+		want bool
+	}{
+		{"/auth/", true},
+		{"/auth", true},
+		{"http://authentik-server:9000/auth/", true},
+		{"/auth/if/user/", false},
+		{"/auth/if/flow/default-authentication-flow/", false},
+	} {
+		if got := isTerminalFlowRedirect(tc.to); got != tc.want {
+			t.Fatalf("isTerminalFlowRedirect(%q) = %v, want %v", tc.to, got, tc.want)
+		}
+	}
+}

internal/authentik/session_cookie.go

@@ -0,0 +1,37 @@
+package authentik
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+)
+
+type sessionClaims struct {
+	Authenticated bool   `json:"authenticated"`
+	Sub           string `json:"sub"`
+}
+
+// SessionAuthenticated reports whether exported cookies contain a logged-in Authentik session.
+func SessionAuthenticated(stored []SerializedCookie) bool {
+	for _, sc := range stored {
+		if sc.Name != "authentik_session" || strings.TrimSpace(sc.Value) == "" {
+			continue
+		}
+		parts := strings.Split(sc.Value, ".")
+		if len(parts) < 2 {
+			continue
+		}
+		raw, err := base64.RawURLEncoding.DecodeString(parts[1])
+		if err != nil {
+			continue
+		}
+		var claims sessionClaims
+		if err := json.Unmarshal(raw, &claims); err != nil {
+			continue
+		}
+		if claims.Authenticated && claims.Sub != "" && claims.Sub != "anonymous" {
+			return true
+		}
+	}
+	return false
+}

internal/authentik/session_cookie_test.go

@@ -0,0 +1,15 @@
+package authentik
+
+import "testing"
+
+func TestSessionAuthenticated(t *testing.T) {
+	t.Parallel()
+	anonymous := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzaWQiOiJhYmMiLCJpc3MiOiJhdXRoZW50aWsiLCJzdWIiOiJhbm9ueW1vdXMiLCJhdXRoZW50aWNhdGVkIjpmYWxzZX0.sig"
+	auth := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzaWQiOiJhYmMiLCJpc3MiOiJhdXRoZW50aWsiLCJzdWIiOiJ1c2VyLTEyMyIsImF1dGhlbnRpY2F0ZWQiOnRydWV9.sig"
+	if SessionAuthenticated([]SerializedCookie{{Name: "authentik_session", Value: anonymous}}) {
+		t.Fatal("expected anonymous session to be rejected")
+	}
+	if !SessionAuthenticated([]SerializedCookie{{Name: "authentik_session", Value: auth}}) {
+		t.Fatal("expected authenticated session")
+	}
+}

internal/server/bootstrap.go

@@ -344,6 +344,7 @@ func New(ctx context.Context, cfg *config.Config, opts Options) (*App, error) {
 
 	r := chi.NewRouter()
 	r.Use(httpcors.Middleware(cfg))
+	r.Use(middleware.ForwardedHeaders)
 	r.Use(middleware.TraceID)
 	r.Use(observability.HTTPMetrics)
 	r.Use(middleware.Logging)
@@ -368,7 +369,7 @@ func New(ctx context.Context, cfg *config.Config, opts Options) (*App, error) {
 	r.Get("/api/v1/mail/addresses/check", mailHandler.CheckAddressAvailability)
 	r.Get("/api/v1/migration/invite", migrationHandler.GetInvite)
 	r.Post("/internal/provision/user", provisionHandler.ProvisionUser)
-	r.Mount("/api/v1/auth", authapi.NewHandler(cfg.AuthentikAPIURL, cfg.MailAppURL, rdb).Routes())
+	r.Mount("/api/v1/auth", authapi.NewHandler(cfg.AuthentikAPIURL, cfg.MailAppURL, cfg.OIDCIssuer, cfg.OIDCClientID, cfg.OIDCClientSecret, rdb).Routes())
 
 	var driveHandler *drive.Handler
 	var driveSvc *drive.Service