encore-auth

Encore Authentication

Instructions

Encore.ts provides a built-in authentication system for identifying API callers and protecting endpoints.

1. Create an Auth Handler

// auth.ts
import { Header, Gateway } from "encore.dev/api";
import { authHandler } from "encore.dev/auth";

// Define what the auth handler receives
interface AuthParams {
  authorization: Header<"Authorization">;
}

// Define what authenticated requests will have access to
interface AuthData {
  userID: string;
  email: string;
  role: "admin" | "user";
}

export const auth = authHandler<AuthParams, AuthData>(
  async (params) => {
    // Validate the token (example with JWT)
    const token = params.authorization.replace("Bearer ", "");
    
    const payload = await verifyToken(token);
    if (!payload) {
      throw APIError.unauthenticated("invalid token");
    }
    
    return {
      userID: payload.sub,
      email: payload.email,
      role: payload.role,
    };
  }
);

// Register the auth handler with a Gateway
export const gateway = new Gateway({
  authHandler: auth,
});

2. Protect Endpoints

import { api } from "encore.dev/api";

// Protected endpoint - requires authentication
export const getProfile = api(
  { method: "GET", path: "/profile", expose: true, auth: true },
  async (): Promise<Profile> => {
    // Only authenticated users reach here
  }
);

// Public endpoint - no authentication required
export const healthCheck = api(
  { method: "GET", path: "/health", expose: true },
  async () => ({ status: "ok" })
);

3. Access Auth Data in Endpoints

import { api } from "encore.dev/api";
import { getAuthData } from "~encore/auth";

export const getProfile = api(
  { method: "GET", path: "/profile", expose: true, auth: true },
  async (): Promise<Profile> => {
    const auth = getAuthData()!;  // Non-null when auth: true
    
    return {
      userID: auth.userID,
      email: auth.email,
      role: auth.role,
    };
  }
);

Auth Handler Behavior

Scenario	Handler Returns	Result
Valid credentials	AuthData object	Request authenticated
Invalid credentials	Throws APIError.unauthenticated()	Treated as no auth
Other error	Throws other error	Request aborted

Auth with Endpoints

Endpoint Config	Request Has Auth	Result
auth: true	Yes	Proceeds with auth data
auth: true	No	401 Unauthenticated
auth: false or omitted	Yes	Proceeds (auth data available)
auth: false or omitted	No	Proceeds (no auth data)

Service-to-Service Auth Propagation

Auth data automatically propagates to internal service calls:

import { user } from "~encore/clients";
import { getAuthData } from "~encore/auth";

export const getOrderWithUser = api(
  { method: "GET", path: "/orders/:id", expose: true, auth: true },
  async ({ id }): Promise<OrderWithUser> => {
    const auth = getAuthData()!;

    // Auth is automatically propagated to this call
    const orderUser = await user.getProfile();

    return { order: await getOrder(id), user: orderUser };
  }
);

Overriding Auth Data

You can explicitly override auth data when making service-to-service calls:

import { user } from "~encore/clients";

// Override auth data for this specific call
const adminUser = await user.getProfile(
  {},
  { authData: { userID: "admin-123", email: "[email protected]", role: "admin" } }
);

Common Auth Patterns

JWT Token Validation

import { jwtVerify } from "jose";
import { secret } from "encore.dev/config";

const jwtSecret = secret("JWTSecret");

async function verifyToken(token: string): Promise<JWTPayload | null> {
  try {
    const { payload } = await jwtVerify(
      token,
      new TextEncoder().encode(jwtSecret())
    );
    return payload;
  } catch {
    return null;
  }
}

API Key Authentication

export const auth = authHandler<AuthParams, AuthData>(
  async (params) => {
    const apiKey = params.authorization;
    
    const user = await db.queryRow<User>`
      SELECT id, email, role FROM users WHERE api_key = ${apiKey}
    `;
    
    if (!user) {
      throw APIError.unauthenticated("invalid API key");
    }
    
    return {
      userID: user.id,
      email: user.email,
      role: user.role,
    };
  }
);

Cookie-Based Auth

interface AuthParams {
  cookie: Header<"Cookie">;
}

export const auth = authHandler<AuthParams, AuthData>(
  async (params) => {
    const sessionId = parseCookie(params.cookie, "session");
    
    if (!sessionId) {
      throw APIError.unauthenticated("no session");
    }
    
    const session = await getSession(sessionId);
    if (!session || session.expiresAt < new Date()) {
      throw APIError.unauthenticated("session expired");
    }
    
    return {
      userID: session.userID,
      email: session.email,
      role: session.role,
    };
  }
);

Testing with Auth

Mock authentication in tests using Vitest:

import { describe, it, expect, vi } from "vitest";
import * as auth from "~encore/auth";
import { getProfile } from "./api";

describe("authenticated endpoints", () => {
  it("returns profile for authenticated user", async () => {
    // Mock getAuthData to return test user
    const spy = vi.spyOn(auth, "getAuthData");
    spy.mockImplementation(() => ({
      userID: "test-user-123",
      email: "[email protected]",
      role: "user",
    }));

    const profile = await getProfile();
    expect(profile.email).toBe("[email protected]");

    spy.mockRestore();
  });
});

The mock does not reach calls made through ~encore/clients. To call an auth: true endpoint on another service from a test, pass { authData: ... } as the second argument (see "Overriding Auth Data" above).

Guidelines

• Auth handlers must be registered with a Gateway
• Use getAuthData() from ~encore/auth to access auth data
• getAuthData() returns null in unauthenticated requests
• Auth data propagates automatically in service-to-service calls
• Throw APIError.unauthenticated() for invalid credentials
• Keep auth handlers fast - they run on every authenticated request