From ca5765b98836a0a17b86aab1a26f850fb43b98f5 Mon Sep 17 00:00:00 2001
From: Daniel Noulet <daniel.noulet@belgiantrain.be>
Date: Sat, 3 Oct 2026 00:14:23 +0200
Subject: [PATCH] feat: integrate tenant SSO and remote toggle

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .github/copilot-instructions.md               |  15 ++-
 Dockerfile                                    |   2 -
 README.md                                     |  86 ++++--------
 backend/cmd/api/main.go                       |  32 +++--
 backend/go.mod                                |   2 +-
 backend/go.sum                                |   4 +-
 backend/internal/config/config.go             |  33 +++++
 backend/internal/golooseauth/registry.go      | 122 ++++++++++++++++++
 backend/internal/service/services.go          |  31 +++++
 backend/internal/web/handler/handler.go       |   5 +-
 backend/internal/web/handler/handler_test.go  |  11 ++
 backend/internal/web/handler/sso.go           |  92 +++++++++++++
 .../web/middleware/TenantSchemaMiddleware.go  |  10 +-
 .../middleware/TenantSchemaMiddleware_test.go |  12 +-
 backend/internal/web/openapi/openapi.go       |   2 -
 backend/internal/web/router/router.go         |  13 +-
 backend/internal/web/router/router_test.go    |  71 +++++++---
 .../go-guess/templates/app-deployment.yaml    |   2 -
 deploy/helm/go-guess/values.yaml              |   2 -
 deploy/nginx/README.md                        |   4 +-
 docker-compose.yml                            |  16 ++-
 frontend/Dockerfile                           |   2 -
 frontend/README.md                            |  30 ++---
 frontend/src/api/client.ts                    |   6 +-
 frontend/src/app/App.tsx                      |   5 +-
 frontend/src/components/actions/Account.tsx   |  50 ++++++-
 scripts/toggle-origin.sh                      |  28 ++++
 27 files changed, 529 insertions(+), 159 deletions(-)
 create mode 100644 backend/internal/golooseauth/registry.go
 create mode 100644 backend/internal/web/handler/sso.go
 create mode 100755 scripts/toggle-origin.sh

diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 748ac28..2694dcb 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -64,11 +64,16 @@ Goose files in `backend/migrations` are schema-only and run in every environment
 Every entity change requires a migration plus corresponding fixture and integration
 test updates. Never put demo users or test records in schema migrations.
 
-Authentication uses bcrypt passwords and HMAC-signed bearer JWTs. Interviewer
-routes additionally require a Go Loose API key for the request tenant. Health,
-OpenAPI, login, and opaque-token participant interview routes do not. Never
-expose password hashes, CV/photo bytes, interviewer reference answers, or API
-keys in public JSON or logs.
+Authentication uses bcrypt passwords and HMAC-signed bearer JWTs. Domain routes are
+protected except `/api/health`, `/api/openapi.json`, `/api/auth/login`,
+`/api/auth/callback`, `/api/auth/logout`, `/api/auth/session`, and opaque-token
+participant interview routes. Tenant hosts `nmbs.guess.dev` and `ypto.guess.dev`
+start login with `github.com/danyel/go-loose/client`: `/api/auth/login` redirects
+to `https://<tenant>.auth.dev/connect/authorize` and Go Loose returns to
+`/api/auth/callback`. Go Loose client credentials come from uncommitted
+environment variables. Missing tenant context uses the public schema; a
+`*.guess.dev` host supplies the schema when `X-Tenant-Id` is absent. Never expose
+password hashes, CV/photo bytes, or interviewer reference answers in public JSON.
 
 Questions are permanent reusable records linked to jobs through
 `job_posting_questions`; detach links rather than deleting questions. Deprecated
diff --git a/Dockerfile b/Dockerfile
index 30ed6b8..76597c4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,8 +4,6 @@ WORKDIR /src/frontend
 COPY frontend/package.json frontend/package-lock.json ./
 RUN npm ci
 COPY frontend/ ./
-ARG VITE_GO_LOOSE_API_KEY
-ENV VITE_GO_LOOSE_API_KEY=$VITE_GO_LOOSE_API_KEY
 RUN npm run build
 
 # Compile the API and seed binaries.
diff --git a/README.md b/README.md
index df0f961..a740172 100644
--- a/README.md
+++ b/README.md
@@ -20,16 +20,17 @@ The complete stack runs with:
 make dev
 ```
 
-Add the local tenant hostnames once:
+`docker compose up -d --build` serves the UI through the local Traefik edge at
+<https://nmbs.guess.dev> and <https://ypto.guess.dev>. Add the hostnames once:
 
 ```text
-127.0.0.1 nmbs.guess.local ypto.guess.local
+127.0.0.1 nmbs.guess.dev ypto.guess.dev
 127.0.0.1 auth.dev nmbs.auth.dev ypto.auth.dev
 ```
 
 Start the shared TLS proxy described in
 `/home/dnoulet/go/infrasctruture/docs/APPLICATIONS.md`, then open
-<https://nmbs.guess.local> or <https://ypto.guess.local>. The hostname's first
+<https://nmbs.guess.dev> or <https://ypto.guess.dev>. The hostname's first
 label is the tenant ID: the frontend calls same-origin `/api` and sends the same value in the
 `X-Tenant-Id` header on JSON, multipart, file-download, and event-stream
 requests. The backend uses that tenant ID as the isolated PostgreSQL schema and
@@ -37,8 +38,10 @@ builds participant invitation and meeting links from the matching tenant browser
 origin instead of the static localhost fallback.
 
 Compose mounts the infrastructure CA from
-`${LOCAL_DEV_CERTS_DIR:-/home/dnoulet/go/infrasctruture/certs}` into the API so
-its HTTPS authorization calls to Go Loose validate normally.
+`${LOCAL_CA_FILE:-../infrastructure/certs/local-ca.crt}` into the API. The
+browser is redirected through the matching Go Loose tenant and returns to
+`/api/auth/callback`. Set the per-tenant `GO_LOOSE_*_CLIENT_ID` and
+`GO_LOOSE_*_CLIENT_SECRET` variables in the environment; never commit them.
 
 Sign in with:
 
@@ -58,15 +61,14 @@ make frontend
 The API listens on port `8080` inside Docker and is exposed to browsers only
 through Traefik and the frontend's same-origin `/api` proxy. Vite permits the
 documented local tenant hostnames; the API CORS policy permits `*.guess.local` development origins and
-the `Authorization`, `X-API-Key`, and `X-Tenant-Id` request headers. Non-local
+the `Authorization` and `X-Tenant-Id` request headers. Non-local
 deployments keep using same-origin `/api`. Set a different secure `JWT_SECRET`
-outside local development. Protected interviewer calls also need a Go Loose API
-key, documented below.
+outside local development.
 
 ## API contract
 
 The backend exposes its current OpenAPI 3.0 contract at
-<https://nmbs.guess.local/api/openapi.json>. The document is assembled in memory
+<https://nmbs.guess.dev/api/openapi.json>. The document is assembled in memory
 from the same typed registrations that add routes to Chi, including request and
 response schemas, status codes, authentication, tenant headers, path/query
 parameters, multipart uploads, downloads, and event streams. It therefore
@@ -74,55 +76,34 @@ requires no generation command and cannot miss a newly registered route.
 
 `/api/openapi.json` and `/api/health` are system endpoints and do not require a
 tenant header. Every other route declares required `X-Tenant-Id`. Protected
-operations also declare `apiKeyAuth` (`X-API-Key`) and `bearerAuth`.
+operations also declare bearer authentication.
 
 ## Go Loose authorization
 
-Interviewer routes are authorized by Go Loose before the JWT check. The tenant
-is read from the request `X-Tenant-Id` header and sent to Go Loose with
-application slug `guess`. It is not taken from process configuration. The client
-calls `POST /api/v1/authorize` on every protected request, removes `X-API-Key`
-before the handler runs, and fails closed on a missing key, a denial, or a
-control-plane error. There is no allow-on-error fallback. The client timeout is
-2 seconds.
+Tenant hosts start browser authentication at `GET /api/auth/login`. Go Loose
+returns to `/api/auth/callback`, and `GET /api/auth/session` exchanges the
+resulting secure browser session for the application's bearer JWT. The tenant
+is derived from the request host, or from `X-Tenant-Id` for API calls.
 
-`GO_LOOSE_BASE_URL` is the authorize base URL. The default is
-`https://%s.auth.dev`. A single `%s` is replaced with the tenant, which must
-then be one DNS label (`nmbs`, not `nmbs.auth.dev` or a host with a port). A
-URL without `%s` is used unchanged, while the tenant still comes from the
-header. Docker Compose passes this variable to the API. Helm sets it from
-`app.goLooseBaseURL`.
-
-These routes do not require `X-API-Key` or a JWT:
+Compose configures `GO_LOOSE_AUTH_DOMAIN`, `GO_LOOSE_APP_DOMAIN`,
+`GO_LOOSE_CA_FILE`, and per-tenant client ID and secret variables. These routes
+do not require a JWT:
 
 - `GET /api/health` and `GET /api/openapi.json`
-- `POST /api/auth/login`
+- browser login, callback, logout, and session routes under `/api/auth`
+- `POST /api/auth/login` for password login outside configured SSO hosts
 - opaque-token participant interview and meeting routes under
   `/api/interviews/{token}` and `/api/participant-meetings/{token}`
 
 Login and participant routes still require `X-Tenant-Id`. Health and OpenAPI do
-not.
+not. Browser authentication routes derive the tenant from the configured host.
 
-Issue one API key per tenant in the Go Loose console for the `guess`
-application. The local installer seed creates that application for `nmbs` and
-`ypto`. For a containerized frontend, pass the key at image build time:
+## Switch the Git remote
 
-```bash
-VITE_GO_LOOSE_API_KEY='gl_replace_with_issued_secret' docker compose build web
-```
-
-For Vite outside Docker, put the same variable in `frontend/.env.local`. That
-file is ignored. Vite inlines `VITE_` variables into the browser bundle, so this
-key is visible to anyone who can load the interviewer application. It identifies
-the Guess application to Go Loose; it does not replace the interviewer JWT or
-the participant token. Do not commit it or reuse a key across tenants.
-
-The published production image does not receive this build argument. A manual
-production image can:
-
-```bash
-docker build --build-arg VITE_GO_LOOSE_API_KEY='gl_replace_with_issued_secret' -t go-guess .
-```
+Run `scripts/toggle-origin.sh` to inspect `origin` and switch it between
+`https://github.com/danyel/go-guess.git` and
+`https://forgejo.dev/exr462/go-guess.git`. The script exits without changing an
+unrecognized remote URL.
 
 ## Quality commands
 
@@ -183,8 +164,7 @@ docker build -t go-guess .
 
 The image serves the frontend and API on port `8080`. It applies database
 migrations and shared production fixtures before startup. PostgreSQL, RabbitMQ,
-and these environment variables must be provided. `GO_LOOSE_BASE_URL` is
-optional and defaults to `https://%s.auth.dev`:
+and these environment variables must be provided:
 
 ```bash
 docker run --rm -p 8080:8080 \
@@ -192,7 +172,6 @@ docker run --rm -p 8080:8080 \
   -e RABBITMQ_URL='amqp://user:password@rabbitmq:5672/' \
   -e JWT_SECRET='replace-with-at-least-32-characters' \
   -e FRONTEND_URL='https://go-guess.example.com' \
-  -e GO_LOOSE_BASE_URL='https://%s.auth.dev' \
   go-guess
 ```
 
@@ -219,15 +198,6 @@ For the repository's single-node Docker Rancher setup, run
 installs the default persistent StorageClass documented in
 `rancher-install.txt`.
 
-The chart passes `app.goLooseBaseURL` to the API as `GO_LOOSE_BASE_URL`. The
-default is `https://%s.auth.dev`. Override it when Go Loose is not reachable
-at `<tenant>.auth.dev`:
-
-```bash
-helm upgrade --install go-guess deploy/helm/go-guess \
-  --set-string app.goLooseBaseURL='https://%s.auth.example.com'
-```
-
 Development uses demo fixtures, ephemeral database and message-broker storage,
 and NodePort `30080`. Production uses production fixtures, persistent volumes,
 generated secrets that are preserved across upgrades, and larger resource
diff --git a/backend/cmd/api/main.go b/backend/cmd/api/main.go
index 3ee70ff..0e7847c 100644
--- a/backend/cmd/api/main.go
+++ b/backend/cmd/api/main.go
@@ -14,6 +14,7 @@ import (
 	"github.com/danyel/go-guess/backend/internal/database"
 	"github.com/danyel/go-guess/backend/internal/database/repository"
 	"github.com/danyel/go-guess/backend/internal/eventbus"
+	"github.com/danyel/go-guess/backend/internal/golooseauth"
 	"github.com/danyel/go-guess/backend/internal/security"
 	"github.com/danyel/go-guess/backend/internal/service"
 	"github.com/danyel/go-guess/backend/internal/web/handler"
@@ -46,21 +47,28 @@ func main() {
 	}
 	defer bus.Close()
 	tokens := security.NewTokenManager(cfg.JWTSecret, cfg.TokenTTL)
+	browser, err := golooseauth.New(cfg.GoLoose)
+	if err != nil {
+		slog.Error("configure Go Loose login", "error", err)
+		os.Exit(1)
+	}
 	invitations := service.NewInvitationService(store, cfg.FrontendURL)
 	interviews := service.NewScheduledInterviewService(store, bus)
+	apiHandler := handler.New(
+		db,
+		service.NewAuthService(store, tokens),
+		service.NewJobService(store),
+		service.NewQuestionService(store),
+		service.NewParticipantService(store),
+		invitations,
+		service.NewUserService(store),
+		interviews,
+		cfg.MaxUploadMB,
+		cfg.FrontendURL,
+	)
+	apiHandler.SetBrowserAuth(browser)
 	api := router.New(
-		handler.New(
-			db,
-			service.NewAuthService(store, tokens),
-			service.NewJobService(store),
-			service.NewQuestionService(store),
-			service.NewParticipantService(store),
-			invitations,
-			service.NewUserService(store),
-			interviews,
-			cfg.MaxUploadMB,
-			cfg.FrontendURL,
-		),
+		apiHandler,
 		tokens,
 		cfg.FrontendURL,
 	)
diff --git a/backend/go.mod b/backend/go.mod
index 83aa22b..25c353d 100644
--- a/backend/go.mod
+++ b/backend/go.mod
@@ -3,7 +3,7 @@ module github.com/danyel/go-guess/backend
 go 1.27.1
 
 require (
-	github.com/danyel/go-loose v0.0.0-20261002165652-46030a5b144f
+	github.com/danyel/go-loose v0.0.0-20261002194542-c2091e746a14
 	github.com/go-chi/chi/v5 v5.2.3
 	github.com/golang-jwt/jwt/v5 v5.3.0
 	github.com/google/uuid v1.6.0
diff --git a/backend/go.sum b/backend/go.sum
index 8d7e738..ba99118 100644
--- a/backend/go.sum
+++ b/backend/go.sum
@@ -22,8 +22,8 @@ github.com/cpuguy83/dockercfg v0.3.2 h1:DlJTyZGBDlXqUZ2Dk2Q3xHs/FtnooJJVaad2S9GK
 github.com/cpuguy83/dockercfg v0.3.2/go.mod h1:sugsbF4//dDlL/i+S+rtpIWp+5h0BHJHfjj5/jFyUJc=
 github.com/creack/pty v1.1.24 h1:bJrF4RRfyJnbTJqzRLHzcGaZK1NeM5kTC9jGgovnR1s=
 github.com/creack/pty v1.1.24/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
-github.com/danyel/go-loose v0.0.0-20261002165652-46030a5b144f h1:9GV60iNpwRsZONzZcFHsGxYNeU0iItiitOvFNLqlkkA=
-github.com/danyel/go-loose v0.0.0-20261002165652-46030a5b144f/go.mod h1:qOO4ay0c2MWiiLwz7WHCXCqDwxxA3sKTKKUnqbFgsOk=
+github.com/danyel/go-loose v0.0.0-20261002194542-c2091e746a14 h1:kX0zybG4E3VLB4QpOsyJEBu4HoXx33CY2x8rtACHRRM=
+github.com/danyel/go-loose v0.0.0-20261002194542-c2091e746a14/go.mod h1:qOO4ay0c2MWiiLwz7WHCXCqDwxxA3sKTKKUnqbFgsOk=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
diff --git a/backend/internal/config/config.go b/backend/internal/config/config.go
index 4355a53..e68a2b1 100644
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -15,6 +15,19 @@ type Config struct {
 	MaxUploadMB int64
 	FrontendURL string
 	RabbitMQURL string
+	GoLoose     GoLooseConfig
+}
+
+type GoLooseConfig struct {
+	AuthDomain string
+	AppDomain  string
+	CAFile     string
+	Tenants    map[string]GoLooseTenant
+}
+
+type GoLooseTenant struct {
+	ClientID     string
+	ClientSecret string
 }
 
 func Load() (Config, error) {
@@ -34,6 +47,7 @@ func Load() (Config, error) {
 		MaxUploadMB: maxUploadMB,
 		FrontendURL: env("FRONTEND_URL", "http://localhost:5173"),
 		RabbitMQURL: env("RABBITMQ_URL", "amqp://guest:guest@localhost:5672/"),
+		GoLoose:     loadGoLoose(),
 	}
 	if len(cfg.JWTSecret) < 32 {
 		return Config{}, fmt.Errorf("JWT_SECRET must contain at least 32 characters")
@@ -41,6 +55,25 @@ func Load() (Config, error) {
 	return cfg, nil
 }
 
+func loadGoLoose() GoLooseConfig {
+	cfg := GoLooseConfig{
+		AuthDomain: env("GO_LOOSE_AUTH_DOMAIN", "auth.dev"),
+		AppDomain:  env("GO_LOOSE_APP_DOMAIN", "guess.dev"),
+		CAFile:     os.Getenv("GO_LOOSE_CA_FILE"),
+		Tenants:    map[string]GoLooseTenant{},
+	}
+	add := func(slug, idEnv, secretEnv string) {
+		id, secret := os.Getenv(idEnv), os.Getenv(secretEnv)
+		if id == "" || secret == "" {
+			return
+		}
+		cfg.Tenants[slug] = GoLooseTenant{ClientID: id, ClientSecret: secret}
+	}
+	add("nmbs", "GO_LOOSE_NMBS_CLIENT_ID", "GO_LOOSE_NMBS_CLIENT_SECRET")
+	add("ypto", "GO_LOOSE_YPTO_CLIENT_ID", "GO_LOOSE_YPTO_CLIENT_SECRET")
+	return cfg
+}
+
 func env(key, fallback string) string {
 	if value := os.Getenv(key); value != "" {
 		return value
diff --git a/backend/internal/golooseauth/registry.go b/backend/internal/golooseauth/registry.go
new file mode 100644
index 0000000..f0e5a7f
--- /dev/null
+++ b/backend/internal/golooseauth/registry.go
@@ -0,0 +1,122 @@
+package golooseauth
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	goloose "github.com/danyel/go-loose/client"
+
+	"github.com/danyel/go-guess/backend/internal/config"
+)
+
+const SessionCookie = "go_loose_user_session"
+
+type Registry struct {
+	appDomain string
+	bySlug    map[string]*goloose.BrowserAuth
+}
+
+func New(cfg config.GoLooseConfig) (*Registry, error) {
+	registry := &Registry{
+		appDomain: strings.TrimPrefix(strings.ToLower(cfg.AppDomain), "."),
+		bySlug:    map[string]*goloose.BrowserAuth{},
+	}
+	if registry.appDomain == "" {
+		registry.appDomain = "guess.dev"
+	}
+	if len(cfg.Tenants) == 0 {
+		return registry, nil
+	}
+	authDomain := strings.TrimPrefix(strings.ToLower(cfg.AuthDomain), ".")
+	if authDomain == "" {
+		return nil, fmt.Errorf("GO_LOOSE_AUTH_DOMAIN is required when client credentials are configured")
+	}
+	httpClient, err := client(cfg.CAFile)
+	if err != nil {
+		return nil, err
+	}
+	for slug, tenant := range cfg.Tenants {
+		slug = strings.ToLower(strings.TrimSpace(slug))
+		if slug == "" || strings.Contains(slug, ".") {
+			return nil, fmt.Errorf("invalid Go Loose tenant slug %q", slug)
+		}
+		auth, err := goloose.NewBrowserAuth(goloose.BrowserAuthConfig{
+			BaseURL:        "https://" + slug + "." + authDomain,
+			ClientID:       tenant.ClientID,
+			ClientSecret:   tenant.ClientSecret,
+			RedirectURL:    "https://" + slug + "." + registry.appDomain + "/api/auth/callback",
+			AfterLoginURL:  "/",
+			AfterLogoutURL: "/",
+			LoginPath:      "/api/auth/login",
+			CookieName:     SessionCookie,
+			CookieSecure:   true,
+			HTTPClient:     httpClient,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("configure %s Go Loose login: %w", slug, err)
+		}
+		registry.bySlug[slug] = auth
+	}
+	return registry, nil
+}
+
+func (r *Registry) AppDomain() string {
+	if r == nil || r.appDomain == "" {
+		return "guess.dev"
+	}
+	return r.appDomain
+}
+
+func (r *Registry) ForHost(host string) (*goloose.BrowserAuth, string, bool) {
+	if r == nil {
+		return nil, "", false
+	}
+	slug := TenantFromHost(host, r.appDomain)
+	auth, ok := r.bySlug[slug]
+	return auth, slug, ok
+}
+
+func TenantFromHost(host, appDomain string) string {
+	hostname := strings.ToLower(host)
+	if parsed, _, err := net.SplitHostPort(host); err == nil {
+		hostname = strings.ToLower(parsed)
+	}
+	appDomain = strings.TrimPrefix(strings.ToLower(appDomain), ".")
+	if appDomain == "" {
+		appDomain = "guess.dev"
+	}
+	suffix := "." + appDomain
+	if !strings.HasSuffix(hostname, suffix) {
+		return ""
+	}
+	slug := strings.TrimSuffix(hostname, suffix)
+	if slug == "" || strings.Contains(slug, ".") {
+		return ""
+	}
+	return slug
+}
+
+func client(caFile string) (*http.Client, error) {
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	if caFile != "" {
+		pem, err := os.ReadFile(caFile)
+		if err != nil {
+			return nil, fmt.Errorf("read Go Loose CA: %w", err)
+		}
+		pool, err := x509.SystemCertPool()
+		if err != nil || pool == nil {
+			pool = x509.NewCertPool()
+		}
+		if !pool.AppendCertsFromPEM(pem) {
+			return nil, fmt.Errorf("parse Go Loose CA %s", caFile)
+		}
+		transport.TLSClientConfig = &tls.Config{RootCAs: pool, MinVersion: tls.VersionTLS12}
+	}
+	return &http.Client{Timeout: 5 * time.Second, Transport: transport}, nil
+}
diff --git a/backend/internal/service/services.go b/backend/internal/service/services.go
index a53e520..b8fb9d7 100644
--- a/backend/internal/service/services.go
+++ b/backend/internal/service/services.go
@@ -28,6 +28,7 @@ const CandidateThreshold = 60.0
 
 type IAuthService interface {
 	Login(context.Context, string, string) (string, model.User, error)
+	EstablishExternalSession(context.Context, string, string) (string, model.User, error)
 }
 
 type IJobService interface {
@@ -88,6 +89,36 @@ func (s *AuthService) Login(ctx context.Context, email, password string) (string
 	return token, user, nil
 }
 
+func (s *AuthService) EstablishExternalSession(ctx context.Context, email, displayName string) (string, model.User, error) {
+	email = strings.ToLower(strings.TrimSpace(email))
+	displayName = strings.TrimSpace(displayName)
+	if email == "" {
+		return "", model.User{}, ErrValidation
+	}
+	user, err := s.store.FindUserByEmail(ctx, email)
+	if errors.Is(err, repository.ErrNotFound) {
+		if displayName == "" {
+			displayName = email
+		}
+		hash, hashErr := security.HashPassword(uuid.NewString())
+		if hashErr != nil {
+			return "", model.User{}, hashErr
+		}
+		user, err = s.store.CreateUser(ctx, model.User{
+			Email: email, DisplayName: displayName, Role: "interviewer", PasswordHash: hash,
+		})
+	}
+	if err != nil {
+		return "", model.User{}, err
+	}
+	token, err := s.tokens.Issue(user.ID, user.Email, user.Role)
+	if err != nil {
+		return "", model.User{}, err
+	}
+	user.PasswordHash = ""
+	return token, user, nil
+}
+
 type JobService struct {
 	store repository.IStore
 }
diff --git a/backend/internal/web/handler/handler.go b/backend/internal/web/handler/handler.go
index 204ed77..ece7e22 100644
--- a/backend/internal/web/handler/handler.go
+++ b/backend/internal/web/handler/handler.go
@@ -19,6 +19,7 @@ import (
 
 	"github.com/danyel/go-guess/backend/internal/database/repository"
 	"github.com/danyel/go-guess/backend/internal/eventbus"
+	"github.com/danyel/go-guess/backend/internal/golooseauth"
 	"github.com/danyel/go-guess/backend/internal/security"
 	"github.com/danyel/go-guess/backend/internal/service"
 	servicemodel "github.com/danyel/go-guess/backend/internal/service/model"
@@ -37,6 +38,7 @@ type Handler struct {
 	interviews   service.IScheduledInterviewService
 	maxUpload    int64
 	frontendURL  string
+	browser      *golooseauth.Registry
 }
 
 func New(
@@ -651,7 +653,8 @@ func (h *Handler) frontendURLForRequest(r *http.Request) string {
 	if err != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") {
 		return h.frontendURL
 	}
-	if strings.EqualFold(parsed.Hostname(), tenant+".guess.local") {
+	if strings.EqualFold(parsed.Hostname(), tenant+".guess.local") ||
+		strings.EqualFold(parsed.Hostname(), tenant+".guess.dev") {
 		return origin
 	}
 	return h.frontendURL
diff --git a/backend/internal/web/handler/handler_test.go b/backend/internal/web/handler/handler_test.go
index 764675a..714da23 100644
--- a/backend/internal/web/handler/handler_test.go
+++ b/backend/internal/web/handler/handler_test.go
@@ -28,3 +28,14 @@ func TestFrontendURLRejectsDifferentTenantOrigin(t *testing.T) {
 		t.Fatalf("expected configured frontend URL, got %q", value)
 	}
 }
+
+func TestFrontendURLAcceptsDevTenantOrigin(t *testing.T) {
+	handler := &Handler{frontendURL: "http://localhost:5173"}
+	request := httptest.NewRequest("GET", "/api/jobs/2/invitations", nil)
+	request.Header.Set("Origin", "https://ypto.guess.dev")
+	request.Header.Set(client.XTenantId, "ypto")
+
+	if value := handler.frontendURLForRequest(request); value != "https://ypto.guess.dev" {
+		t.Fatalf("expected tenant dev origin, got %q", value)
+	}
+}
diff --git a/backend/internal/web/handler/sso.go b/backend/internal/web/handler/sso.go
new file mode 100644
index 0000000..5d799e0
--- /dev/null
+++ b/backend/internal/web/handler/sso.go
@@ -0,0 +1,92 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+
+	goloose "github.com/danyel/go-loose/client"
+
+	"github.com/danyel/go-guess/backend/internal/golooseauth"
+	webmapper "github.com/danyel/go-guess/backend/internal/web/mapper"
+	webmodel "github.com/danyel/go-guess/backend/internal/web/model"
+)
+
+var (
+	errMissingSession = errors.New("missing Go Loose session")
+	errTenantMismatch = errors.New("Go Loose session does not match this tenant")
+)
+
+func (h *Handler) SetBrowserAuth(auth *golooseauth.Registry) {
+	h.browser = auth
+}
+
+func (h *Handler) AppDomain() string {
+	if h.browser == nil {
+		return "guess.dev"
+	}
+	return h.browser.AppDomain()
+}
+
+func (h *Handler) BeginExternalLogin(w http.ResponseWriter, r *http.Request) {
+	auth, ok := h.externalAuth(r)
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+	auth.LoginHandler(w, r)
+}
+
+func (h *Handler) CompleteExternalLogin(w http.ResponseWriter, r *http.Request) {
+	auth, ok := h.externalAuth(r)
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+	auth.CallbackHandler(w, r)
+}
+
+func (h *Handler) ExternalLogout(w http.ResponseWriter, r *http.Request) {
+	auth, ok := h.externalAuth(r)
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+	auth.LogoutHandler(w, r)
+}
+
+func (h *Handler) ExternalSession(w http.ResponseWriter, r *http.Request) {
+	auth, slug, ok := h.externalAuthWithSlug(r)
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+	if _, err := r.Cookie(golooseauth.SessionCookie); err != nil {
+		writeError(w, http.StatusUnauthorized, errMissingSession)
+		return
+	}
+	auth.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user, ok := goloose.UserFromContext(r.Context())
+		if !ok || user.TenantSlug != slug {
+			writeError(w, http.StatusForbidden, errTenantMismatch)
+			return
+		}
+		token, local, err := h.auth.EstablishExternalSession(r.Context(), user.Email, user.DisplayName)
+		if err != nil {
+			internalError(w, r, err)
+			return
+		}
+		writeJSON(w, http.StatusOK, webmodel.LoginResponse{Token: token, User: webmapper.UserToWeb(local)})
+	})).ServeHTTP(w, r)
+}
+
+func (h *Handler) externalAuth(r *http.Request) (*goloose.BrowserAuth, bool) {
+	auth, _, ok := h.externalAuthWithSlug(r)
+	return auth, ok
+}
+
+func (h *Handler) externalAuthWithSlug(r *http.Request) (*goloose.BrowserAuth, string, bool) {
+	if h.browser == nil {
+		return nil, "", false
+	}
+	return h.browser.ForHost(r.Host)
+}
diff --git a/backend/internal/web/middleware/TenantSchemaMiddleware.go b/backend/internal/web/middleware/TenantSchemaMiddleware.go
index 56b68a8..67e92cf 100644
--- a/backend/internal/web/middleware/TenantSchemaMiddleware.go
+++ b/backend/internal/web/middleware/TenantSchemaMiddleware.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"regexp"
 
+	"github.com/danyel/go-guess/backend/internal/golooseauth"
 	"github.com/danyel/go-loose/client"
 	"gorm.io/gorm"
 )
@@ -18,7 +19,7 @@ const TxKey contextKey = "tenant_db_tx"
 var safeSchemaRegex = regexp.MustCompile(`^[a-zA-Z0-9_:-]+$`)
 
 // TenantSchemaMiddleware isolates database connections per request using PostgreSQL schemas
-func TenantSchemaMiddleware(db *gorm.DB) func(http.Handler) http.Handler {
+func TenantSchemaMiddleware(db *gorm.DB, appDomain string) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if r.URL.Path == "/api/health" || r.URL.Path == "/api/openapi.json" {
@@ -27,9 +28,10 @@ func TenantSchemaMiddleware(db *gorm.DB) func(http.Handler) http.Handler {
 			}
 			tenantID := r.Header.Get(client.XTenantId)
 			if tenantID == "" {
-				w.Header().Set("Content-Type", "application/json")
-				w.WriteHeader(http.StatusBadRequest)
-				_, _ = w.Write([]byte(`{"error": "Missing X-Tenant-Id header"}`))
+				tenantID = golooseauth.TenantFromHost(r.Host, appDomain)
+			}
+			if tenantID == "" || db == nil {
+				next.ServeHTTP(w, r)
 				return
 			}
 
diff --git a/backend/internal/web/middleware/TenantSchemaMiddleware_test.go b/backend/internal/web/middleware/TenantSchemaMiddleware_test.go
index d968acc..5d9e5bb 100644
--- a/backend/internal/web/middleware/TenantSchemaMiddleware_test.go
+++ b/backend/internal/web/middleware/TenantSchemaMiddleware_test.go
@@ -10,7 +10,7 @@ func TestTenantMiddlewareAllowsSystemEndpointsWithoutTenant(t *testing.T) {
 	next := http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		w.WriteHeader(http.StatusOK)
 	})
-	handler := TenantSchemaMiddleware(nil)(next)
+	handler := TenantSchemaMiddleware(nil, "guess.dev")(next)
 
 	for _, path := range []string{"/api/health", "/api/openapi.json"} {
 		response := httptest.NewRecorder()
@@ -21,15 +21,15 @@ func TestTenantMiddlewareAllowsSystemEndpointsWithoutTenant(t *testing.T) {
 	}
 }
 
-func TestTenantMiddlewareStillRequiresTenantForDataEndpoints(t *testing.T) {
-	handler := TenantSchemaMiddleware(nil)(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
-		t.Fatal("data endpoint reached without a tenant")
+func TestTenantMiddlewareUsesPublicSchemaWithoutTenant(t *testing.T) {
+	handler := TenantSchemaMiddleware(nil, "guess.dev")(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
 	}))
 	response := httptest.NewRecorder()
 
 	handler.ServeHTTP(response, httptest.NewRequest(http.MethodGet, "/api/jobs", nil))
 
-	if response.Code != http.StatusBadRequest {
-		t.Fatalf("expected 400, got %d", response.Code)
+	if response.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", response.Code)
 	}
 }
diff --git a/backend/internal/web/openapi/openapi.go b/backend/internal/web/openapi/openapi.go
index ad0f60c..b70bf28 100644
--- a/backend/internal/web/openapi/openapi.go
+++ b/backend/internal/web/openapi/openapi.go
@@ -89,7 +89,6 @@ func (b *Builder) Add(method, path string, operation Operation) {
 	}
 	if operation.Protected {
 		value["security"] = []map[string][]string{{
-			"apiKeyAuth": {},
 			"bearerAuth": {},
 		}}
 	}
@@ -131,7 +130,6 @@ func (b *Builder) Document() map[string]any {
 		"paths":   b.paths,
 		"components": map[string]any{
 			"securitySchemes": map[string]any{
-				"apiKeyAuth": map[string]any{"type": "apiKey", "in": "header", "name": client.DefaultHeader},
 				"bearerAuth": map[string]any{"type": "http", "scheme": "bearer", "bearerFormat": "JWT"},
 			},
 			"schemas": b.schemas,
diff --git a/backend/internal/web/router/router.go b/backend/internal/web/router/router.go
index bc98870..a9003fe 100644
--- a/backend/internal/web/router/router.go
+++ b/backend/internal/web/router/router.go
@@ -22,12 +22,22 @@ func New(h *handler.Handler, tokens security.ITokenManager, frontendURL string)
 	spec := openapi.New()
 	router.Use(middleware.RequestID, middleware.RealIP, middleware.Recoverer, middleware.Compress(5))
 	router.Use(cors(frontendURL))
-	router.Use(mw.TenantSchemaMiddleware(h.Db()))
+	router.Use(mw.TenantSchemaMiddleware(h.Db(), h.AppDomain()))
 	router.Use(middleware.Timeout(2 * time.Minute))
 	register(router, spec, false, http.MethodGet, "/api/openapi.json", spec.ServeHTTP,
 		openapi.Operation{Summary: "Get the current OpenAPI contract", Response: map[string]any{}, NoTenant: true})
 	register(router, spec, false, http.MethodGet, "/api/health", h.Health,
 		openapi.Operation{Summary: "Check API health", Response: map[string]string{}, NoTenant: true})
+	register(router, spec, false, http.MethodGet, "/api/auth/login", h.BeginExternalLogin,
+		openapi.Operation{Summary: "Start Go Loose browser authentication", NoTenant: true})
+	register(router, spec, false, http.MethodGet, "/api/auth/callback", h.CompleteExternalLogin,
+		openapi.Operation{Summary: "Complete Go Loose browser authentication", NoTenant: true})
+	register(router, spec, false, http.MethodGet, "/api/auth/logout", h.ExternalLogout,
+		openapi.Operation{Summary: "End the Go Loose browser session", NoTenant: true})
+	register(router, spec, false, http.MethodPost, "/api/auth/logout", h.ExternalLogout,
+		openapi.Operation{Summary: "End the Go Loose browser session", NoTenant: true})
+	register(router, spec, false, http.MethodGet, "/api/auth/session", h.ExternalSession,
+		openapi.Operation{Summary: "Exchange a Go Loose browser session for an API token", Response: webmodel.LoginResponse{}, NoTenant: true})
 	register(router, spec, false, http.MethodPost, "/api/auth/login", h.Login,
 		openapi.Operation{Summary: "Authenticate an interviewer", Request: webmodel.LoginRequest{}, Response: webmodel.LoginResponse{}})
 	register(router, spec, false, http.MethodGet, "/api/interviews/{token}", h.GetInterview,
@@ -43,7 +53,6 @@ func New(h *handler.Handler, tokens security.ITokenManager, frontendURL string)
 	register(router, spec, false, http.MethodGet, "/api/participant-meetings/{token}/events", h.ParticipantMeetingEvents,
 		openapi.Operation{Summary: "Stream participant meeting events", Response: eventbus.InterviewEvent{}, ResponseContentType: "text/event-stream"})
 	router.Group(func(protected chi.Router) {
-		protected.Use(mw.GoLooseMiddleware())
 		protected.Use(authenticate(tokens))
 		register(protected, spec, true, http.MethodGet, "/api/jobs", h.ListJobs,
 			openapi.Operation{Summary: "List job postings", Response: []webmodel.JobResponse{}})
diff --git a/backend/internal/web/router/router_test.go b/backend/internal/web/router/router_test.go
index dde7dd7..c4011d7 100644
--- a/backend/internal/web/router/router_test.go
+++ b/backend/internal/web/router/router_test.go
@@ -9,10 +9,13 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
 
+	"github.com/danyel/go-guess/backend/internal/config"
 	"github.com/danyel/go-guess/backend/internal/eventbus"
+	"github.com/danyel/go-guess/backend/internal/golooseauth"
 	"github.com/danyel/go-guess/backend/internal/security"
 	"github.com/danyel/go-guess/backend/internal/service"
 	"github.com/danyel/go-guess/backend/internal/service/model"
@@ -24,7 +27,6 @@ import (
 
 const (
 	testTenant = "ypto"
-	testAPIKey = "gl_test_key_that_is_long_enough_for_client"
 )
 
 func init() {
@@ -45,16 +47,6 @@ func openStubDB(t *testing.T) *gorm.DB {
 	return db
 }
 
-func allowGoLoose(t *testing.T) {
-	t.Helper()
-	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		_, _ = w.Write([]byte(`{"allowed":true,"tenant_slug":"ypto","application_slug":"guess","api_key_name":"guess"}`))
-	}))
-	t.Cleanup(server.Close)
-	t.Setenv("GO_LOOSE_BASE_URL", server.URL)
-}
-
 func newTestHandler(t *testing.T, interviews service.IScheduledInterviewService) *handler.Handler {
 	t.Helper()
 	if interviews == nil {
@@ -71,16 +63,16 @@ func withTenant(request *http.Request) {
 	request.Header.Set(client.XTenantId, testTenant)
 }
 
-func withAPIKey(request *http.Request) {
-	request.Header.Set(client.DefaultHeader, testAPIKey)
-}
-
 type authStub struct{}
 
 func (authStub) Login(context.Context, string, string) (string, model.User, error) {
 	return "", model.User{}, service.ErrInvalidCredentials
 }
 
+func (authStub) EstablishExternalSession(context.Context, string, string) (string, model.User, error) {
+	return "", model.User{}, service.ErrInvalidCredentials
+}
+
 type jobStub struct{}
 
 func (jobStub) List(context.Context) ([]model.JobPosting, error)    { return []model.JobPosting{}, nil }
@@ -237,13 +229,11 @@ func TestHealthDoesNotRequireAuthentication(t *testing.T) {
 }
 
 func TestProtectedRouteRequiresValidToken(t *testing.T) {
-	allowGoLoose(t)
 	tokens := security.NewTokenManager("01234567890123456789012345678901", time.Hour)
 	router := New(newTestHandler(t, nil), tokens, "http://localhost:5173")
 
 	unauthorizedRequest := httptest.NewRequest(http.MethodGet, "/api/jobs", nil)
 	withTenant(unauthorizedRequest)
-	withAPIKey(unauthorizedRequest)
 	unauthorized := httptest.NewRecorder()
 	router.ServeHTTP(unauthorized, unauthorizedRequest)
 	if unauthorized.Code != http.StatusUnauthorized || unauthorized.Header().Get("Content-Type") != "application/json" {
@@ -255,7 +245,6 @@ func TestProtectedRouteRequiresValidToken(t *testing.T) {
 	}
 	request := httptest.NewRequest(http.MethodGet, "/api/jobs", nil)
 	withTenant(request)
-	withAPIKey(request)
 	request.Header.Set("Authorization", "Bearer "+token)
 	authorized := httptest.NewRecorder()
 	router.ServeHTTP(authorized, request)
@@ -265,7 +254,6 @@ func TestProtectedRouteRequiresValidToken(t *testing.T) {
 }
 
 func TestProtectedInterviewUsesAuthenticatedUserID(t *testing.T) {
-	allowGoLoose(t)
 	interviews := &interviewCapture{}
 	tokens := security.NewTokenManager("01234567890123456789012345678901", time.Hour)
 	api := New(newTestHandler(t, interviews), tokens, "http://localhost:5173")
@@ -275,7 +263,6 @@ func TestProtectedInterviewUsesAuthenticatedUserID(t *testing.T) {
 	}
 	request := httptest.NewRequest(http.MethodGet, "/api/scheduled-interviews/9", nil)
 	withTenant(request)
-	withAPIKey(request)
 	request.Header.Set("Authorization", "Bearer "+token)
 	response := httptest.NewRecorder()
 	api.ServeHTTP(response, request)
@@ -310,6 +297,50 @@ func TestParticipantMeetingDoesNotExposeInternalCandidateData(t *testing.T) {
 	}
 }
 
+func TestOpenAPIDoesNotRequireTenant(t *testing.T) {
+	api := New(
+		newTestHandler(t, nil),
+		security.NewTokenManager("01234567890123456789012345678901", time.Hour),
+		"http://localhost:5173",
+	)
+	response := httptest.NewRecorder()
+	api.ServeHTTP(response, httptest.NewRequest(http.MethodGet, "/api/openapi.json", nil))
+	if response.Code != http.StatusOK || !bytes.Contains(response.Body.Bytes(), []byte(`"openapi"`)) {
+		t.Fatalf("expected OpenAPI document, got %d %s", response.Code, response.Body.Bytes())
+	}
+}
+
+func TestTenantHostLoginRedirectsToMatchingGoLooseClient(t *testing.T) {
+	h := newTestHandler(t, nil)
+	browser, err := golooseauth.New(config.GoLooseConfig{
+		AuthDomain: "auth.dev",
+		AppDomain:  "guess.dev",
+		Tenants: map[string]config.GoLooseTenant{
+			"nmbs": {ClientID: "glc_nmbs", ClientSecret: "secret"},
+			"ypto": {ClientID: "glc_ypto", ClientSecret: "secret"},
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	h.SetBrowserAuth(browser)
+	api := New(h, security.NewTokenManager("01234567890123456789012345678901", time.Hour), "http://localhost:5173")
+
+	for _, slug := range []string{"nmbs", "ypto"} {
+		request := httptest.NewRequest(http.MethodGet, "/api/auth/login", nil)
+		request.Host = slug + ".guess.dev"
+		response := httptest.NewRecorder()
+		api.ServeHTTP(response, request)
+		location := response.Header().Get("Location")
+		if response.Code != http.StatusFound || !strings.HasPrefix(location, "https://"+slug+".auth.dev/connect/authorize?") {
+			t.Fatalf("%s login redirect = %d %s", slug, response.Code, location)
+		}
+		if !strings.Contains(location, "redirect_uri=https%3A%2F%2F"+slug+".guess.dev%2Fapi%2Fauth%2Fcallback") {
+			t.Fatalf("%s callback missing from %s", slug, location)
+		}
+	}
+}
+
 type stubDriver struct{}
 
 func (stubDriver) Open(string) (driver.Conn, error) { return stubConn{}, nil }
diff --git a/deploy/helm/go-guess/templates/app-deployment.yaml b/deploy/helm/go-guess/templates/app-deployment.yaml
index c25caed..d271706 100644
--- a/deploy/helm/go-guess/templates/app-deployment.yaml
+++ b/deploy/helm/go-guess/templates/app-deployment.yaml
@@ -48,8 +48,6 @@ spec:
               value: {{ .Values.app.tokenTTL | quote }}
             - name: MAX_UPLOAD_MB
               value: {{ .Values.app.maxUploadMB | quote }}
-            - name: GO_LOOSE_BASE_URL
-              value: {{ .Values.app.goLooseBaseURL | quote }}
             - name: DATABASE_URL
               valueFrom:
                 secretKeyRef:
diff --git a/deploy/helm/go-guess/values.yaml b/deploy/helm/go-guess/values.yaml
index 3dc2eb3..6537aa2 100644
--- a/deploy/helm/go-guess/values.yaml
+++ b/deploy/helm/go-guess/values.yaml
@@ -15,8 +15,6 @@ app:
   frontendURL: http://localhost:8080
   tokenTTL: 8h
   maxUploadMB: 10
-  # Authorize URL for Go Loose. %s is the request X-Tenant-Id.
-  goLooseBaseURL: https://%s.auth.dev
 
 secrets:
   jwtSecret: ""
diff --git a/deploy/nginx/README.md b/deploy/nginx/README.md
index 23cfc4b..37d990c 100644
--- a/deploy/nginx/README.md
+++ b/deploy/nginx/README.md
@@ -58,5 +58,5 @@ services should remain `ClusterIP` services without NodePorts.
 Protected interviewer routes also call Go Loose from the application pod, using
 `app.goLooseBaseURL` (default `https://%s.auth.dev`, where `%s` is the
 request tenant). That address must be reachable from the cluster. The browser
-sends `X-API-Key` only when the published frontend image was built with
-`VITE_GO_LOOSE_API_KEY`. Nginx does not add or strip that header.
+forwards browser authentication and API requests without adding application
+credentials. Nginx does not add or strip authorization headers.
diff --git a/docker-compose.yml b/docker-compose.yml
index e469c0f..78f3869 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -37,8 +37,13 @@ services:
       JWT_SECRET: local-development-secret-change-me-12345
       FRONTEND_URL: ${FRONTEND_URL:-https://nmbs.guess.local}
       APP_ENV: ${APP_ENV:-development}
-      GO_LOOSE_BASE_URL: ${GO_LOOSE_BASE_URL:-https://%s.auth.dev}
-      SSL_CERT_FILE: /certs/local-ca.crt
+      GO_LOOSE_AUTH_DOMAIN: auth.dev
+      GO_LOOSE_APP_DOMAIN: guess.dev
+      GO_LOOSE_CA_FILE: /certs/local-ca.crt
+      GO_LOOSE_NMBS_CLIENT_ID: ${GO_LOOSE_NMBS_CLIENT_ID:-}
+      GO_LOOSE_NMBS_CLIENT_SECRET: ${GO_LOOSE_NMBS_CLIENT_SECRET:-}
+      GO_LOOSE_YPTO_CLIENT_ID: ${GO_LOOSE_YPTO_CLIENT_ID:-}
+      GO_LOOSE_YPTO_CLIENT_SECRET: ${GO_LOOSE_YPTO_CLIENT_SECRET:-}
       RABBITMQ_URL: amqp://guest:guest@rabbitmq:5672/
     expose:
       - "8080"
@@ -46,7 +51,7 @@ services:
       - go_guess_network
       - local_dev_edge
     volumes:
-      - ${LOCAL_DEV_CERTS_DIR:-/home/dnoulet/go/infrasctruture/certs}/local-ca.crt:/certs/local-ca.crt:ro
+      - ${LOCAL_CA_FILE:-../infrastructure/certs/local-ca.crt}:/certs/local-ca.crt:ro
     depends_on:
       db:
         condition: service_healthy
@@ -54,10 +59,7 @@ services:
         condition: service_healthy
 
   web:
-    build:
-      context: ./frontend
-      args:
-        VITE_GO_LOOSE_API_KEY: ${VITE_GO_LOOSE_API_KEY:-}
+    build: ./frontend
     expose:
       - "80"
     depends_on:
diff --git a/frontend/Dockerfile b/frontend/Dockerfile
index fcefeea..16970b8 100644
--- a/frontend/Dockerfile
+++ b/frontend/Dockerfile
@@ -3,8 +3,6 @@ WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci
 COPY . .
-ARG VITE_GO_LOOSE_API_KEY
-ENV VITE_GO_LOOSE_API_KEY=$VITE_GO_LOOSE_API_KEY
 RUN npm run build
 
 FROM nginx:1.29-alpine
diff --git a/frontend/README.md b/frontend/README.md
index 6992669..47bf688 100644
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -36,27 +36,15 @@ application shell.
 
 ## API integration
 
-For local tenant hosts such as `nmbs.guess.local`, `src/api/client.ts` derives
+For local tenant hosts such as `nmbs.guess.dev`, `src/api/client.ts` derives
 tenant `nmbs`, calls same-origin `/api` through the shared HTTPS proxy, and sends
 `X-Tenant-Id: nmbs` on every JSON, multipart, file-download, and event-stream
-request. `ypto.guess.local` behaves identically for tenant `ypto`. Other
+request. `ypto.guess.dev` behaves identically for tenant `ypto`. Other
 hostnames use same-origin `/api`; Vite retains its `/api` proxy for that case.
 
-Set `VITE_GO_LOOSE_API_KEY` before `npm run dev` or `npm run build` to also send
-`X-API-Key`. Vite reads `frontend/.env.local` for local development; that file
-matches `*.local` and must not be committed. The standalone frontend image
-accepts the same value as a build argument:
-
-```bash
-docker build --build-arg VITE_GO_LOOSE_API_KEY='gl_replace_with_issued_secret' \
-  -t go-guess-frontend .
-```
-
-The variable is inlined into the JavaScript bundle. Treat it as an application
-credential for Go Loose, not as a secret equivalent to the interviewer JWT. If
-it is unset or empty, the client omits the header and protected interviewer
-routes fail closed with 401. Login and participant routes do not require the
-key, but the client still sends it when the variable is present.
+On the configured tenant hosts, the app checks `/api/auth/session` and redirects
+to `/api/auth/login` when no Go Loose browser session exists. The callback
+exchanges that session for the bearer token used by the typed API client.
 Invitation and participant-meeting URLs use the validated request origin so
 links stay on the tenant hostname. Copy actions fall back to a temporary selected
 textarea when the Clipboard API is unavailable on local HTTP domains.
@@ -65,7 +53,9 @@ Login stores the returned JWT in
 `sessionStorage`; protected requests send it as `Authorization: Bearer <token>`. API failures are
 shown in the UI and are never replaced with demo data. A `401` from a protected
 JSON, file, or event-stream request clears authentication and returns the user to
-`/login`. The app also schedules logout from the JWT expiration claim so an idle
+`/login`. On `nmbs.guess.dev` and `ypto.guess.dev`, the app restores
+`/api/auth/session` or redirects to `/api/auth/login`; participant routes stay
+token-based. The app also schedules logout from the JWT expiration claim so an idle
 expired session cannot remain on a protected page.
 
 The machine-readable OpenAPI 3.0 contract at `/api/openapi.json` is the source
@@ -120,7 +110,5 @@ receives interviewer notes or assessment reference answers.
 
 ## Container
 
-Build with `docker build -t go-guess-frontend .`. Pass
-`--build-arg VITE_GO_LOOSE_API_KEY=...` when the image must call protected
-interviewer routes; see the API integration section. The production Nginx server
+Build with `docker build -t go-guess-frontend .`. The production Nginx server
 serves the SPA and proxies `/api` to the Docker Compose service `api:8080`.
diff --git a/frontend/src/api/client.ts b/frontend/src/api/client.ts
index 006830a..7ee208e 100644
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -93,11 +93,7 @@ function apiURL(path: string): string {
 
 function tenantHeader(): Record<string, string> {
   const tenant = tenantFromHostname(window.location.hostname)
-  const apiKey = import.meta.env.VITE_GO_LOOSE_API_KEY
-  return {
-    ...(tenant ? { 'X-Tenant-Id': tenant } : {}),
-    ...(typeof apiKey === 'string' && apiKey !== '' ? { 'X-API-Key': apiKey } : {}),
-  }
+  return tenant ? { 'X-Tenant-Id': tenant } : {}
 }
 
 async function request<T>(
diff --git a/frontend/src/app/App.tsx b/frontend/src/app/App.tsx
index 04a610c..711df6c 100644
--- a/frontend/src/app/App.tsx
+++ b/frontend/src/app/App.tsx
@@ -9,7 +9,7 @@ import {DataProvider} from './DataContext'
 
 export default function App() {
     const location = useLocation();
-    const {authenticated, sessionExpired, completeLogin, logout} = useAuthSession();
+    const {authenticated, sessionExpired, ssoStatus, completeLogin, logout} = useAuthSession();
     if (location.pathname.startsWith('/participant/')) {
         return (
             <Routes>
@@ -20,6 +20,9 @@ export default function App() {
         )
     }
     if (!authenticated) {
+        if (ssoStatus !== 'idle') {
+            return <main className="login-shell"><p>Redirecting to sign in…</p></main>
+        }
         return <LoginPage onLogin={completeLogin} sessionExpired={sessionExpired}/>
     }
     return (
diff --git a/frontend/src/components/actions/Account.tsx b/frontend/src/components/actions/Account.tsx
index 4b21720..51743bf 100644
--- a/frontend/src/components/actions/Account.tsx
+++ b/frontend/src/components/actions/Account.tsx
@@ -1,16 +1,31 @@
 import { useEffect, useState } from 'react'
-import { useNavigate } from 'react-router-dom'
+import { useLocation, useNavigate } from 'react-router-dom'
 import { authStorage, invalidateSession, SESSION_EXPIRED_EVENT } from '../../api/client'
 
+const ssoHosts = new Set(['nmbs.guess.dev', 'ypto.guess.dev'])
+
+export function isSSOHost() {
+  return ssoHosts.has(window.location.hostname)
+}
+
 export function useAuthSession() {
+  const location = useLocation()
+  const sso = isSSOHost() && !location.pathname.startsWith('/participant/')
   const [authenticated, setAuthenticated] = useState(() => Boolean(authStorage.token()))
   const [sessionExpired, setSessionExpired] = useState(false)
+  const [redirecting, setRedirecting] = useState(false)
+  const needsSSO = sso && !authenticated && !authStorage.token()
+  const ssoStatus = !needsSSO ? 'idle' : redirecting ? 'redirecting' : 'checking'
   const navigate = useNavigate()
 
   useEffect(() => {
     function handleSessionExpired() {
       setAuthenticated(false)
       setSessionExpired(true)
+      if (isSSOHost() && !window.location.pathname.startsWith('/participant/')) {
+        window.location.replace('/api/auth/login')
+        return
+      }
       navigate('/login', { replace: true })
     }
 
@@ -18,6 +33,36 @@ export function useAuthSession() {
     return () => window.removeEventListener(SESSION_EXPIRED_EVENT, handleSessionExpired)
   }, [navigate])
 
+  useEffect(() => {
+    if (!needsSSO) return
+    let cancelled = false
+    void (async () => {
+      try {
+        const response = await fetch('/api/auth/session', {
+          headers: { Accept: 'application/json' },
+          credentials: 'same-origin',
+          redirect: 'manual',
+        })
+        if (cancelled) return
+        if (response.ok) {
+          authStorage.save(await response.json())
+          setAuthenticated(true)
+          setSessionExpired(false)
+          return
+        }
+      } catch {
+        // The browser redirect below starts a fresh Go Loose login.
+      }
+      if (!cancelled) {
+        setRedirecting(true)
+        window.location.replace('/api/auth/login')
+      }
+    })()
+    return () => {
+      cancelled = true
+    }
+  }, [needsSSO])
+
   useEffect(() => {
     if (!authenticated) return
     const expiresAt = authStorage.expiresAt()
@@ -41,7 +86,8 @@ export function useAuthSession() {
     authStorage.clear()
     setAuthenticated(false)
     setSessionExpired(false)
+    if (isSSOHost()) window.location.assign('/api/auth/logout')
   }
 
-  return { authenticated, sessionExpired, completeLogin, logout }
+  return { authenticated, sessionExpired, ssoStatus, completeLogin, logout }
 }
diff --git a/scripts/toggle-origin.sh b/scripts/toggle-origin.sh
new file mode 100755
index 0000000..bc6098e
--- /dev/null
+++ b/scripts/toggle-origin.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+set -eu
+
+github_url='https://github.com/danyel/go-guess.git'
+forgejo_url='https://forgejo.dev/exr462/go-guess.git'
+remote='origin'
+
+current_url=$(git remote get-url "$remote")
+case "$current_url" in
+	"$github_url")
+		target_url=$forgejo_url
+		;;
+	"$forgejo_url")
+		target_url=$github_url
+		;;
+	*)
+		printf 'Refusing to change %s: unrecognized URL %s\n' "$remote" "$current_url" >&2
+		exit 1
+		;;
+esac
+
+git remote set-url "$remote" "$target_url"
+if git config --get-all "remote.$remote.pushurl" >/dev/null; then
+	git config --replace-all "remote.$remote.pushurl" "$target_url"
+fi
+
+printf '%s now uses %s\n' "$remote" "$(git remote get-url "$remote")"