Authentication

Add user signup, login, OAuth, and session management to your app without building any auth infrastructure. Redirect users to our hosted login, get a token back.

1Quick start

Create a project in your dashboard, grab your client_id, and add a redirect URI.

2Redirect to hosted login

Send your users to our login page. We handle the UI, email verification, and OAuth providers.

const loginUrl = "https://astapa.com/auth/login";
const params = new URLSearchParams({
  client_id: "your_client_id",
  redirect_uri: "https://yourapp.com/callback",
});

window.location.href = `${loginUrl}?${params}`;

3Exchange the code for a token

After login, the user is redirected back with an authorization code. Exchange it server-side for an access token.

callback.tstypescript

const code = searchParams.get("code");

const res = await fetch("https://astapa.com/api/platform/token", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    grant_type: "authorization_code",
    code,
    client_id: process.env.CLIENT_ID,
    client_secret: process.env.CLIENT_SECRET,
    redirect_uri: "https://yourapp.com/callback",
  }),
});

const { access_token, refresh_token } = await res.json();

4Verify the token

The access token is a signed JWT (RS256). Verify it using our JWKS endpoint or decode it directly with the public key.

middleware.tstypescript

import jwt from "jsonwebtoken";

const decoded = jwt.verify(access_token, publicKey, {
  algorithms: ["RS256"],
});

// decoded.sub   → end user ID
// decoded.email → user email
// decoded.claims → custom claims (plan, role, etc.)

Authentication

1Quick start

2Redirect to hosted login

3Exchange the code for a token

4Verify the token

API reference

Next steps