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1. Install dependencies

npm install @civic/auth

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2. Configure your App

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Minimal Configuration

const config = {
  clientId: "YOUR_CLIENT_ID", // Client ID from auth.civic.com
  redirectUrl: 'https://your-backend.com/auth/callback' // change to your domain when deploying
};
Note: All URLs must be absolute URLs.

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3. Set up CORS (for frontend integration)

If your frontend runs on a different domain/port, configure CORS to enable cross-origin cookie sharing: 
import { cors } from 'hono/cors';

app.use(
  cors({
    origin: [
      "http://localhost:5173", // frontend (local development)
      "http://localhost:3020", // backend (local development)
      "https://abc123.ngrok.io", // ngrok tunnel (for cross-origin testing)
      "https://your-frontend.com", // production frontend
    ],
    credentials: true, // Allow cookies to be sent cross-origin
    allowMethods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
    allowHeaders: ['Content-Type', 'Authorization', 'Cookie'],
    exposeHeaders: ['Set-Cookie'],
  }),
);
Important: Cross-origin cookies (different ports/domains) require HTTPS to work properly. For local development with separate frontend/backend ports, use ngrok or similar service to create HTTPS tunnels: 
# Terminal 1: Start your backend
npm start

# Terminal 2: Create HTTPS tunnel to your backend
ngrok http 3020
# Use the https://abc123.ngrok.io URL as your backend URL

# Terminal 3: Create HTTPS tunnel to your frontend
ngrok http 5173
# Use the https://xyz456.ngrok.io URL as your frontend URL
The cookie storage automatically detects HTTPS and sets secure: true + sameSite: "none" for cross-origin compatibility. Without HTTPS, cross-origin cookies will not be saved by the browser.

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4. Set up Cookies

Civic Auth uses cookies for storing the login state by default 
import { Context } from 'hono';
import { getCookie, setCookie, deleteCookie } from 'hono/cookie';
import { CookieStorage, CivicAuth } from '@civic/auth/server';

class HonoCookieStorage extends CookieStorage {
  constructor(private c: Context) {
    // Detect if we're running on HTTPS (production) or HTTP (localhost)
    const isHttps = c.req.header('x-forwarded-proto') === 'https' || 
                    c.req.url.startsWith('https://');

    super({
      secure: isHttps, // Use secure cookies for HTTPS
      sameSite: isHttps ? "none" : "lax", // none for HTTPS cross-origin, lax for localhost
      httpOnly: false, // Allow frontend JavaScript to access cookies
      path: "/", // Ensure cookies are available for all paths
    });
  }

  async get(key: string) {
    return getCookie(this.c, key) ?? null;
  }

  async set(key: string, value: string): Promise<void> {
    setCookie(this.c, key, value, this.settings);
  }

  async delete(key: string): Promise<void> {
    deleteCookie(this.c, key);
  }
}

// Middleware to attach CookieStorage and civicAuth API to each request
app.use('*', async (c, next) => {
  const storage = new HonoCookieStorage(c)
  c.set('storage', storage);
  c.set('civicAuth', new CivicAuth(storage, config));
  return next();
});

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5. Create a Login Endpoint

This endpoint will handle login requests, build the Civic login URL and redirect the user to it. 
import { buildLoginUrl } from '@civic/auth/server';

app.get('/', async (c) => {
  const url = await c.get('civicAuth').buildLoginUrl();

  return c.redirect(url.toString());
});

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6. Create the Callback Endpoint

This endpoint handles successful logins and creates the session 
app.get('/auth/callback', async (c) => {
  const code = c.req.query('code') as string
  const state = c.req.query('state') as string

  try {
    const result = await c.get('civicAuth').handleCallback({
      code,
      state,
      req: c.req,
    });

    if (result.redirectTo) {
      return c.redirect(result.redirectTo);
    }

    if (result.content) {
      return c.html(result.content);
    }

    return c.json({ error: "Internal server error" }, 500);
  } catch (error) {
    return c.redirect("/?error=auth_failed");
  }
});

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7. Create a Logout Endpoint

This endpoint will handle logout requests, build the Civic logout URL and redirect the user to it. 
import { buildLogoutRedirectUrl } from '@civic/auth/server';

app.get('/auth/logout', async (c) => {
  try {
    const urlString = await c.get('civicAuth').buildLogoutRedirectUrl({
      postLogoutRedirectUrl: 'https://your-frontend.com/' // Optional: where to redirect after logout
    });
    await c.get('civicAuth').clearTokens();

    // Convert to URL object to modify parameters
    const url = new URL(urlString);
    // Remove the state parameter to avoid it showing up in the frontend URL
    url.searchParams.delete("state");

    return c.redirect(url.toString());
  } catch (error) {
    console.error("Logout error:", error);
    // If logout URL generation fails, clear tokens and redirect to home
    await c.get('civicAuth').clearTokens();
    return c.redirect("/");
  }
});

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8. Add Middleware

Middleware protects routes that require login. 
import { isLoggedIn } from '@civic/auth/server';

const authMiddleware = async (c: Context, next: Function) => {
  if (!(await c.get('civicAuth').isLoggedIn())) return c.text('Unauthorized', 401);
  return next();
};

// Apply authentication middleware to any routes that need it
app.use('/admin/*', authMiddleware);

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9. Use the Session

If needed, get the logged-in user information. 
import { user } from '@civic/auth/server';

app.get('/admin/hello', async (c) => {
  const user = await c.get('civicAuth').getUser();
  return c.text(`Hello, ${user?.name}!`);
});

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10. Frontend Integration (Vanilla JavaScript)

Use the @civic/auth/vanillajs client with your backend: 
import { CivicAuth } from "@civic/auth/vanillajs";

// Configure client to use your backend for login URLs
const authClient = await CivicAuth.create({
  loginUrl: "https://your-backend.com/auth/login-url", // Your backend endpoint
});

// Now authentication works through your backend
const { user } = await authClient.startAuthentication();
Add this endpoint to expose login URLs: 
app.get("/auth/login-url", async (c) => {
  const loginUrl = await c.get('civicAuth').buildLoginUrl();
  return c.json({ loginUrl: loginUrl.toString() });
});

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Advanced Configuration

For more advanced use cases, you can include additional optional parameters in your configuration: 
const config = {
  clientId: "YOUR_CLIENT_ID", // Client ID from auth.civic.com
  redirectUrl: 'https://your-backend.com/auth/callback', // OAuth callback URL
  postLogoutRedirectUrl: 'https://your-frontend.com/', // Where to redirect after logout (Optional)
  loginSuccessUrl: 'https://your-frontend.com/', // Optional: redirect Single Page Applications back to frontend after auth (optional)
  oauthServer: 'https://auth.civic.com/oauth' // Optional: OAuth server URL (for development/testing) 
};
ParameterRequiredDescription
clientIdYesClient ID from auth.civic.com
redirectUrlYesOAuth 2.0 callback URL - The backend endpoint where Civic redirects after authentication to complete the token exchange (e.g., https://your-backend.com/auth/callback). This URL must be registered in your Civic Auth dashboard under “Domains”.
postLogoutRedirectUrlNoWhere to redirect users after logout
loginSuccessUrlNoPost-authentication redirect - After your backend completes authentication, redirect the user to this URL (typically your frontend). Use this when your frontend (SPA) calls your backend to initiate login. If not set, the callback endpoint will return a success response instead of redirecting.
oauthServerNoOAuth server URL (useful for development/testing environments)

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PKCE and Client Secrets

Civic Auth supports multiple OAuth 2.0 authentication methods to provide maximum security for different application architectures.
Need client secret authentication? Civic Auth supports PKCE-only, client secrets, and hybrid PKCE + client secret approaches. See our Authentication Flows guide for detailed comparison.
The examples above use PKCE authentication, which is handled entirely by the Civic Auth SDK and suitable for most applications.