---
title: Authentication
description: Pick a credential, wire getToken, sign people in headlessly, add Sign in with Kortix to your own app, and isolate requests on a server.
---

Every SDK request carries one bearer credential. `createKortix` reads it from
your `getToken` function and sends it as `Authorization: Bearer <token>`. This
page is for developers who call Kortix from a script, a backend, or an app
that people sign in to.

```ts
import { createKortix } from '@kortix/sdk';

const kortix = createKortix({
  backendUrl: 'https://api.kortix.com/v1',
  getToken: async () => process.env.KORTIX_API_KEY ?? null,
});

await kortix.projects.list();
```

On a self-hosted instance, set `backendUrl` to `<your API origin>/v1`.

## Choose a credential

Pick the row that matches the caller. A credential holds the roles of the
principal it acts as, and nothing more.

| Caller | Credential | Acts as | Get it |
|---|---|---|---|
| A script, a CI job, your own backend | Personal access key, `kortix_pat_` | You, with your roles. Optionally one project only. | **Settings → Personal access keys**, or `kortix tokens new` |
| Unattended automation that must not act as a person | Service account key, `kortix_sa_` | The service account. It has no access until you assign it a role. | **Account settings → API keys**, or `kortix tokens service-accounts new` |
| Your product, where people sign in with their Kortix email, password, magic link, social login or SSO | The person's access token from [headless sign-in](#headless-sign-in) | The person who signed in | `kortix.auth.*` + `createKortixSession` |
| Your own web app with a "Sign in with Kortix" button | OAuth access token, `kortix_oat_` (1 hour; refresh token `kortix_ort_`, 30 days) | The person who approved your app | [`createKortixAuth`](#sign-in-with-kortix) |
| Code inside a Kortix App | App viewer token. The App's viewer scope must be `api`. | The person viewing the App, capped by their role | `kortix apps access <app> --viewer api`, then `kortixAppViewerToken()`. See [Apps](/docs/apps#know-who-is-looking). |
| Code inside a session sandbox | `KORTIX_TOKEN` | The session's agent (its service account), limited to that project and session. Its permissions are the agent's `kortix_permissions` capped by its ceiling role. See [What an agent may do](/docs/project/agents#what-an-agent-may-do). | Kortix sets it, with `KORTIX_API_URL` as the `backendUrl`. See [Sandboxes & previews](/docs/work/runtime#environment-variables). |

Creation, expiry, project binding and key rules are in
[API keys and tokens](/docs/accounts/identity#api-keys-and-tokens).
A web app that already signs people in through the instance's Supabase passes
that JWT:
`getToken: async () => (await supabase.auth.getSession()).data.session?.access_token ?? null`.
New code uses [headless sign-in](#headless-sign-in) instead. A valid
credential without the needed permission gets `403`. Grant the role in
[Accounts & access](/docs/accounts).

## getToken and 401 recovery

The SDK calls `getToken` before every request. It caches nothing, so your code
owns token storage and refresh.

- `getToken` returns `null`: the SDK sends no request and throws `AuthError`
  with `code: 'NO_SESSION'`.
- The API answers `401`: the SDK calls `getToken.invalidate(rejectedToken)`
  when you attached one, calls `getToken` again, and replays the request once
  with the new token. A second `401` goes to the caller.
- Parallel `401`s on the same token share one `invalidate` call and one
  `getToken` call. A host that rotates a refresh token per call is not raced
  by its own requests.
- The SDK does not replay when the new token equals the rejected one, when the
  request body is a `ReadableStream`, or when the caller set its own
  `Authorization` header.

A `getToken` that caches must attach `invalidate`. Without it, the second
`getToken` call returns the same dead token and the SDK does not replay.
`session.getToken` from `createKortixSession` has no `invalidate`. A `401` on a
token that has not expired goes to the caller: handle it with `isAuthFailure`.

```ts
let cached: string | null = null;

const getToken = Object.assign(
  async () => (cached ??= await fetchTokenFromMyServer()),
  { invalidate: (rejected: string) => { if (cached === rejected) cached = null; } },
);

const kortix = createKortix({ backendUrl: 'https://api.kortix.com/v1', getToken });
```

To branch on an auth failure, use `isAuthFailure(error)`. It is `true` for
`AuthError` and for any error with `status` `401` or `403`. It reads the
status, never the message text.

```ts
import { isAuthFailure } from '@kortix/sdk';

try {
  await kortix.projects.list();
} catch (error) {
  if (isAuthFailure(error)) redirectToSignIn();
  else throw error;
}
```

Set `clientVersion` to your app's name and version, for example
`clientVersion: 'my-app/1.4.0'`. The SDK sends it as `X-Kortix-Client-Version`.
Kortix writes it to request logs only. It grants nothing and never reaches the
audit log, which records the credential `getToken` returned.

## Headless sign-in

`kortix.auth.*` signs people up and in through the Kortix API at `/v1/auth/*`.
It needs no Supabase URL or key and works the same on Kortix Cloud and on a
self-hosted instance. Use it for a CLI, a native app, or your own sign-in
screen.

Create one session store and one client. The store keeps the tokens,
refreshes them 60 s before they expire, and feeds `getToken`.

```ts
import { createKortix, createKortixSession } from '@kortix/sdk';

const session = createKortixSession({
  storage: {                                   // optional: anything with get/set/remove
    get: () => localStorage.getItem('kortix'),
    set: (value) => localStorage.setItem('kortix', value),
    remove: () => localStorage.removeItem('kortix'),
  },
});

const kortix = createKortix({
  backendUrl: 'https://api.kortix.com/v1',
  getToken: session.getToken,
});

const { session: tokens, user } = await kortix.auth.signInWithPassword({ email, password });
await session.set(tokens, user);

await kortix.projects.list();                  // runs as that person
```

Create the store with `createKortixSession` directly. Do not build a second
`createKortix` client only to reach `kortix.auth.session`: every
`createKortix` call shares one process-wide config, and the SDK warns when a
second call changes `getToken`.

### Sign-in flows

| Flow | Calls |
|---|---|
| Sign up | `auth.signUp({ email, password, data?, redirect_to? })` returns `{ user, session, requires_email_confirmation }`. When `requires_email_confirmation` is `true`, `session` is `null` until the person confirms with the emailed link or with `verifyOtp({ type: 'signup' })`. |
| Password | `auth.signInWithPassword({ email, password })` |
| Magic link or code | `auth.sendMagicLink({ email, create_user?, redirect_to?, data? })`, then `auth.verifyOtp({ email, token, type: 'magiclink' })` with the code from the email |
| Social login (PKCE) | `auth.signInWithProvider({ provider, redirect_to, scopes? })` returns `{ url, code_verifier }`. Keep `code_verifier`, send the browser to `url`, then call `auth.exchangeCode({ code, code_verifier })` with the `code` from the redirect. `provider` is one the instance has configured, for example `google` or `github`. |
| Enterprise SSO | `auth.signInWithSso({ domain, redirect_to? })` returns `{ url }` to send the browser to. A `404` means the domain has no identity provider. See [Single sign-on](/docs/accounts/identity#single-sign-on-saml). |
| Password reset | `auth.resetPassword({ email, redirect_to? })`, then `auth.verifyOtp({ email, token, type: 'recovery' })`, then `auth.updatePassword({ password }, session.access_token)` with the session `verifyOtp` returned. The new password is 8 to 256 characters. |

Every flow that returns a session returns `{ session, user }`. Pass both to
`session.set(...)`. `redirect_to` must be an absolute `http` or `https` URL that
the instance allows.

### The signed-in person

These calls take a token as an argument, so they work before `getToken` is
wired. `user`, `updateUserMetadata`, `updatePassword` and `mfa.*` need the
person's own access token. They refuse any other credential, such as a
personal access key, with `401 invalid_token`.

| Call | Does |
|---|---|
| `auth.user(accessToken)` | Returns `{ user }` |
| `auth.updateUserMetadata({ data }, accessToken)` | Writes profile metadata: display name, avatar, language. A password or email change is refused. |
| `auth.updatePassword({ password }, accessToken)` | Sets a new password |
| `auth.mfa.enroll({ factor_type, friendly_name?, phone?, issuer? }, accessToken)` | Enrolls a `totp` or `phone` factor |
| `auth.mfa.challenge(factorId, { channel? }, accessToken)` | Starts a challenge |
| `auth.mfa.verify(factorId, { challenge_id, code }, accessToken)` | Verifies the code. Returns the new token pair at the second assurance level at the top level (`access_token`, `refresh_token`, `expires_at`), not as `{ session, user }`. Store it with `session.set(result as AuthSession)`. |
| `auth.mfa.unenroll(factorId, accessToken)` | Removes a factor |
| `auth.refresh({ refresh_token })` | Rotates the token pair. `createKortixSession` calls it for you. |
| `auth.signOut(accessToken, { scope? })` | Revokes the session at Kortix. `scope`: `global` (default, every device), `local` (this session), `others` (every other session). |

To sign out, revoke the session, then clear the store:

```ts
const token = await session.getToken();
if (token) await kortix.auth.signOut(token);
await session.clear();
```

### The session store

`kortix.auth.session(options?)` is the same function as
`createKortixSession(options?)`. Each call creates a new store, so create one
and keep it.

| Option | Default | Does |
|---|---|---|
| `storage` | none, memory only | `{ get, set, remove }`, sync or async: `localStorage`, a file, a cookie jar, a database row |
| `onChange` | none | Called after every sign-in, refresh and sign-out |
| `refreshSkewSeconds` | `60` | Refresh this many seconds before expiry |
| `request` | the client's `backendUrl` | `{ backendUrl?, fetch?, signal? }` for refresh calls |

| Method | Does |
|---|---|
| `getToken()` | A valid access token, refreshed first when needed. `null` when signed out. |
| `set(session, user?)` | Stores a session a `kortix.auth.*` call returned |
| `current()`, `user()` | The stored session and user. No refresh. |
| `refresh()` | Rotates now. Concurrent callers share one refresh. |
| `subscribe(listener)` | Calls `listener` on every change. Returns an unsubscribe function. |
| `load()` | Reads storage now instead of on first use |
| `clear()` | Forgets the session locally. Call `auth.signOut` first to revoke it. |

A refresh that Kortix rejects with a `4xx` signs the person out: the store
clears itself and `getToken()` returns `null`. A network failure keeps the
stored session for the next call.

### Errors and limits

Every `kortix.auth.*` call throws `HeadlessAuthError` with `code`, `message` and
`status`.

| `code` | `status` | Cause |
|---|---|---|
| `sso_required` | `403` | The email's domain must sign in with SSO. Sign-up, password and magic link refuse it. Use `signInWithSso`. |
| `signup_closed` | `403` | The instance does not accept sign-ups from this address |
| `over_request_rate_limit` | `429` | Too many attempts. Wait for the `retry-after` header. |
| `invalid_token` | `401` | A call that needs the person's access token got another credential |
| `not_configured` | `0` | No `backendUrl`: create the client first |

All public `/v1/auth/*` routes share one limit: 30 attempts per minute per
client IP, counted on each API replica. Other codes come unchanged from the identity service.

## Sign in with Kortix

Sign in with Kortix makes Kortix the identity provider for a web app you run.
People sign in with their Kortix account. Your server knows who they are, and
your app calls Kortix as that person, with that person's roles. It is OAuth 2.1
with PKCE, and the browser never holds a Kortix token.

1. **Register your app**

    Open **Account settings → API keys → OAuth apps** and select **Register app**, or
    register it in code. Registering needs `token.create` on the account.

    ```ts
    const app = await kortix.iam.oauthClients.create(accountId, {
      name: 'My dashboard',
      client_type: 'confidential',   // 'public' for a browser or native app: PKCE, no secret
      redirect_uris: ['https://dashboard.example.com/api/kortix/auth/callback'],
      scopes: ['profile', 'email', 'kortix'],
    });
    // app.client_id; app.client_secret is shown once
    ```

    Kortix compares redirect URIs byte for byte. They must use `https`, except
    on a loopback host (`localhost`, `*.localhost`, `127.0.0.1`, `[::1]`). `kortix.iam.oauthClients` also has `list`, `get`, `update`,
    `rotateSecret` and `remove`. Field details are in
    [OAuth apps and connected apps](/docs/accounts/identity#oauth-apps-and-connected-apps).

2. **Create the auth kit on your server**

    ```ts
    // lib/kortix-auth.ts (server only)
    import { createKortixAuth } from '@kortix/sdk/server';

    export const auth = createKortixAuth({
      backendUrl: 'https://api.kortix.com/v1',
      clientId: process.env.KORTIX_OAUTH_CLIENT_ID!,
      clientSecret: process.env.KORTIX_OAUTH_CLIENT_SECRET,   // omit for a public client
      redirectUri: 'https://dashboard.example.com/api/kortix/auth/callback',
      cookieSecret: process.env.KORTIX_AUTH_COOKIE_SECRET!,   // at least 32 characters
    });
    ```

3. **Mount one catch-all route**

    ```ts
    // app/api/kortix/auth/[...kortix]/route.ts (Next.js App Router)
    import { auth } from '@/lib/kortix-auth';

    const handle = (request: Request) => auth.handler(request);
    export { handle as GET, handle as POST };
    ```

    Any framework works: pass a Web `Request` to `auth.handler` and return its
    `Response`.

4. **Gate pages and call Kortix as the person**

    ```ts
    import { auth } from '@/lib/kortix-auth';

    export async function GET(request: Request) {
      const gate = await auth.requireViewer(request);
      if (gate.response) return gate.response;          // 302 to /refresh or /signin

      const kortix = await auth.kortix(request);        // acts as the signed-in person
      return Response.json(await kortix.projects.list());
    }
    ```

5. **Call Kortix from the browser**

    ```tsx
    import { createKortix } from '@kortix/sdk';
    import { SignInWithKortix, useKortixViewer } from '@kortix/sdk/react';

    const kortix = createKortix({
      backendUrl: window.location.origin + '/api/kortix/auth/proxy',
      getToken: async () => 'kortix-session',
    });

    function Header() {
      const { status, viewer } = useKortixViewer();
      if (status === 'signed-in') return <span>{viewer.email}</span>;
      return <SignInWithKortix className="button" />;
    }
    ```

    The browser sends the placeholder bearer `kortix-session`. The `/proxy`
    route replaces it with the person's real token on your server. Every SDK
    call works through it, including [`useSession`](/docs/sdk/react).

> **Warning**
>
> Never import `@kortix/sdk/server` or a module that imports it, such as
> `lib/kortix-auth.ts`, into browser code. It pulls in `node:async_hooks`, and
> `createKortixAuth` throws without `cookieSecret`. Write the browser config
> literally, as in step 5.

### Options

| Option | Default | Does |
|---|---|---|
| `backendUrl` | required | Kortix API base, including `/v1` |
| `clientId` | required | The registered client id |
| `clientSecret` | none | The client secret. Omit it for a public client. |
| `redirectUri` | required | Absolute callback URL, identical to a registered one |
| `cookieSecret` | required | At least 32 characters. Encrypts the cookies with AES-256-GCM. |
| `scopes` | `['profile', 'email', 'kortix']` | Scopes to request |
| `basePath` | the `redirectUri` path without `/callback` | Where `handler` is mounted |
| `sessionTtlSeconds` | `2592000` (30 days) | How long a session lives without a new sign-in |
| `cookieSameSite` | `'lax'` | `'none'` only for an app that signs in while embedded in another origin. It needs `https`; over `http` the cookie stays `Lax`. |
| `fetch` | global `fetch` | Custom fetch for tests or edge runtimes |

| Scope | Grants your app |
|---|---|
| `profile` | The person's id, email and account memberships |
| `email` | The email address |
| `kortix` | Acting as the person on the whole Kortix API. Without it the token reaches only the identity routes. |

### Routes the handler serves

All paths are under `basePath`, `/api/kortix/auth` in the example.

| Path | Does |
|---|---|
| `/signin?return_to=/path` | Starts sign-in with PKCE and a 10-minute transaction cookie, then redirects to Kortix |
| `/callback` | Exchanges the code, sets the encrypted `HttpOnly` session cookie, redirects to `return_to` |
| `/refresh?return_to=/path` | Rotates the token pair and redirects. `requireViewer` sends people here. |
| `/signout?return_to=/path` | Revokes the refresh token at Kortix and clears the cookie |
| `/me` | The person as JSON, or `401`. Refreshes an expired access token. |
| `/proxy/*` | Forwards the request to the Kortix API as the person |

`return_to` is always reduced to a same-origin path. When the person declines
consent, the callback redirects to `return_to` with `?kortix_auth_error=<code>`.
A missing or expired transaction answers `400` with `error: 'state_mismatch'`.
A failed code exchange answers with `error: 'token_exchange_failed'`.

### Server and browser API

| From | API | Returns |
|---|---|---|
| `@kortix/sdk/server` | `auth.viewer(request)` | `{ userId, email, accounts, scopes, token, expiresAt }` or `null`. Read-only: it never rotates the refresh token. |
| `@kortix/sdk/server` | `auth.requireViewer(request)` | `{ viewer }`, or `{ response }` with a redirect to `/refresh` or `/signin` |
| `@kortix/sdk/server` | `auth.kortix(request)` | A request-scoped client that acts as the person. Throws `KortixAuthError` `unauthenticated` when signed out. |
| `@kortix/sdk/server` | `auth.signInUrl(returnTo?)`, `auth.signOutUrl(returnTo?)` | Link targets |
| `@kortix/sdk/react` | `useKortixViewer({ basePath? })` | `{ status, viewer, reload }`. `status` is `loading`, `signed-in`, `signed-out` or `error`. |
| `@kortix/sdk/react` | `<SignInWithKortix basePath? returnTo? />` | A link that starts sign-in and returns to the current page |
| `@kortix/sdk/react` | `kortixSignOutHref(basePath?, returnTo?)` | The sign-out link target |

Use `requireViewer` to gate a page. A page then never renders signed out for a
person whose refresh token is still valid. `createKortixAuth` throws
`KortixAuthError` with code `invalid_options` when `backendUrl` or `clientId`
is empty, `redirectUri` is not an absolute `http` or `https` URL, or
`cookieSecret` is shorter than 32 characters.

`useKortixViewer`, `<SignInWithKortix>` and `kortixSignOutHref` default
`basePath` to `/api/kortix/auth`. Pass `basePath` when you mount `handler`
elsewhere.

### What the person sees

The first sign-in shows a Kortix consent screen with your app's name and
scopes. Kortix remembers the approval per person and app, so later sign-ins
return straight to your app. People revoke an app in code with
`kortix.accounts.connectedApps.list()` and `.revoke(clientId)`, or on the web
and in the CLI as described in
[Connected apps](/docs/accounts/identity#oauth-apps-and-connected-apps). After a revoke the
app's tokens stop working and the app must ask again.

### Discovery for other OAuth clients

The SDK derives every endpoint from `backendUrl`. A generic OAuth client reads
`GET /.well-known/oauth-authorization-server` on the API origin, also served at
`/v1/oauth/.well-known/oauth-authorization-server`. Open dynamic client
registration is at `POST /v1/oauth/register`. Kortix deletes a self-registered
client after 7 days when it has no approval and no token.

## Servers that act for many users

`createKortix` stores its config in one process-wide slot. That is correct for
a browser tab, a CLI or a single-tenant job. On a server that handles requests
for different people at the same time, the last `createKortix` call wins for
every request in flight. Use `@kortix/sdk/server` instead. It isolates each
request's config in Node's `AsyncLocalStorage` and runs in Node and Bun.

**One client per request.** `createScopedKortix` has the same shape as
`createKortix` and never touches the global config.

```ts
import { createScopedKortix } from '@kortix/sdk/server';

export async function GET(request: Request) {
  const kortix = createScopedKortix({
    backendUrl: 'https://api.kortix.com/v1',
    getToken: async () => tokenFor(request),
  });
  return Response.json(await kortix.projects.list());
}
```

A scoped client's top-level `kortix.runtime()` throws, because it would resolve
another request's sandbox. Reach a session's runtime through its handle:
`const s = kortix.session(projectId, sessionId); await s.ensureReady(); s.runtime`.

**One scope per request.** `runWithKortix(config, fn)` sets the config for
everything `fn` awaits, including calls on a client made with `createKortix`.

```ts
import { runWithKortix } from '@kortix/sdk/server';

app.use(async (req, res, next) => {
  await runWithKortix(
    { backendUrl: 'https://api.kortix.com/v1', getToken: async () => tokenFor(req) },
    async () => next(),
  );
});
```

**A proxy for your browser code.** `forwardKortixRequest` forwards one request
from your own route to the Kortix API with a token your server holds.

```ts
import { forwardKortixRequest } from '@kortix/sdk/server';

export async function handle(request: Request) {
  const url = new URL(request.url);
  const rest = url.pathname.replace(/^\/api\/kortix\//, '');
  return forwardKortixRequest({
    request,
    upstreamUrl: 'https://api.kortix.com/v1/' + rest + url.search,
    token: await tokenFor(request),
  });
}
```

It removes the browser's `cookie` and `host` headers, sets the bearer, keeps
streamed response bodies, and removes `set-cookie` from the answer. When Kortix
is unreachable it answers `502` with `{ "error": "Upstream request failed" }`.
Point the browser client at the route with any non-null placeholder token:
`createKortix({ backendUrl: '/api/kortix', getToken: async () => 'proxy' })`.

To start sessions from such a server with session secrets and idempotency, see
[Start sessions from your server](/docs/sdk/sessions#start-sessions-from-your-server).