Developer Guide

Linbik Integration

Connect your application to Linbik's authentication gateway in minutes

Register Community

Create your community and get Client ID + RSA public key

Redirect Users

Send users to /auth/{clientId} for authentication

Verify JWT

Receive JWT token and verify with RSA public key

Authentication Flow

User Clicks "Login with Linbik"

Your application redirects user to Linbik with your Client ID

https://linbik.com/auth/YOUR_CLIENT_ID

User Authenticates on Linbik

User logs in (or uses existing session) and selects profile

John Doe

@johndoe

JWT Token Issued

Linbik signs a JWT with your community's private RSA key


                                    eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiIxMjMiLCJ1c2VyTmFtZSI6ImpvaG5kb2UiLCJuaWNrTmFtZSI6IkpvaG4gRG9lIiwiY29kZSI6InRlc3QiLCJleHAiOjE3MzAwMDAwMDB9.signature

User Redirected to Your App

Token sent to your registered callback URL

https://yourapp.com/callback?token=JWT_HERE

You Verify & Create Session

Verify JWT signature with public key and extract user info

✓ JWT Valid - User Authenticated

userId: 123, userName: johndoe, nickName: John Doe

JWT Token Claims

Claim	Type	Description	Example
userId	string	Unique user identifier (GUID)	"a1b2c3d4-..."
userName	string	Unique username (profile handle)	"johndoe"
nickName	string	Display name	"John Doe"
code	string	Custom code parameter (optional)	"test"
exp	number	Expiration timestamp (3 minutes)	1730000000

Code Examples

Node.js + Express

Popular

const express = require('express');
const jwt = require('jsonwebtoken');
const fs = require('fs');

const app = express();
const publicKey = fs.readFileSync('linbik_public_key.pem', 'utf8');

// Callback endpoint
app.get('/callback', (req, res) => {
  const token = req.query.token;
  
  try {
    const decoded = jwt.verify(token, publicKey, { 
      algorithms: ['RS256'] 
    });
    
    // User authenticated!
    const userId = decoded.userId;
    const userName = decoded.userName;
    const nickName = decoded.nickName;
    
    // Create your own session
    req.session.userId = userId;
    
    res.redirect('/dashboard');
  } catch (error) {
    res.status(401).send('Invalid token');
  }
});

app.listen(3000);

Python + Flask

from flask import Flask, request, redirect, session
import jwt

app = Flask(__name__)
app.secret_key = 'your-secret-key'

# Load public key
with open('linbik_public_key.pem', 'r') as f:
    public_key = f.read()

@app.route('/callback')
def callback():
    token = request.args.get('token')
    
    try:
        # Verify JWT
        decoded = jwt.decode(
            token, 
            public_key, 
            algorithms=['RS256']
        )
        
        # Store in session
        session['user_id'] = decoded['userId']
        session['user_name'] = decoded['userName']
        session['nick_name'] = decoded['nickName']
        
        return redirect('/dashboard')
    except jwt.InvalidTokenError:
        return 'Invalid token', 401

if __name__ == '__main__':
    app.run(port=3000)

PHP

<?php
require_once 'vendor/autoload.php';
use \Firebase\JWT\JWT;
use \Firebase\JWT\Key;

// Load public key
$publicKey = file_get_contents('linbik_public_key.pem');
$token = $_GET['token'];

try {
    // Verify JWT
    $decoded = JWT::decode(
        $token, 
        new Key($publicKey, 'RS256')
    );
    
    // Start session
    session_start();
    $_SESSION['user_id'] = $decoded->userId;
    $_SESSION['user_name'] = $decoded->userName;
    $_SESSION['nick_name'] = $decoded->nickName;
    
    header('Location: /dashboard');
} catch (Exception $e) {
    http_response_code(401);
    echo 'Invalid token';
}
?>

C# / ASP.NET Core

using Microsoft.AspNetCore.Mvc;
using System.IdentityModel.Tokens.Jwt;
using Microsoft.IdentityModel.Tokens;
using System.Security.Cryptography;

public class CallbackController : Controller
{
    [HttpGet("/callback")]
    public IActionResult Callback(string token)
    {
        var publicKey = File.ReadAllText("linbik_public_key.pem");
        var rsa = RSA.Create();
        rsa.ImportFromPem(publicKey);
        
        var validationParameters = new TokenValidationParameters
        {
            IssuerSigningKey = new RsaSecurityKey(rsa),
            ValidateIssuer = false,
            ValidateAudience = false
        };
        
        try
        {
            var handler = new JwtSecurityTokenHandler();
            var principal = handler.ValidateToken(
                token, validationParameters, out var validatedToken
            );
            
            var userId = principal.FindFirst("userId")?.Value;
            var userName = principal.FindFirst("userName")?.Value;
            
            // Create your session...
            
            return Redirect("/dashboard");
        }
        catch
        {
            return Unauthorized("Invalid token");
        }
    }
}

HTML + Vanilla JavaScript

<!DOCTYPE html>
<html>
<head>
    <title>Linbik Login</title>
</head>
<body>
    <button onclick="loginWithLinbik()">
        Login with Linbik
    </button>
    
    <script>
        const CLIENT_ID = 'YOUR_CLIENT_ID_HERE';
        
        function loginWithLinbik() {
            // Redirect to Linbik
            window.location.href = 
                `https://linbik.com/auth/${CLIENT_ID}`;
        }
        
        // Handle callback (on your callback page)
        const urlParams = new URLSearchParams(window.location.search);
        const token = urlParams.get('token');
        
        if (token) {
            // Send to your backend for verification
            fetch('/api/verify-token', {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ token })
            })
            .then(res => res.json())
            .then(data => {
                console.log('User authenticated:', data);
                window.location.href = '/dashboard';
            });
        }
    </script>
</body>
</html>

Need Help?

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