Authentication

Overview

The inspir API uses JWT (JSON Web Token) authentication. Tokens are issued upon signup or login and remain valid for 7 days. Authentication flow:

User signs up or logs in
Server returns a JWT token
Client includes token in Authorization header for subsequent requests
Server validates token and identifies user

Authentication Types

The API supports three authentication patterns:

Public

No authentication required. Anyone can access.

Optional Auth

Works for guests, enhanced for authenticated users.

Required Auth

Must be authenticated. Returns 401 if not logged in.

Getting a Token

Create a new account and receive a JWT token:

POST /api/auth/signup

Request body:

username

string

required

Username (alphanumeric, underscores, hyphens only)

password

string

required

Password (minimum 6 characters)

confirmPassword

string

required

Password confirmation (must match password)

Example request:

curl -X POST https://api.inspir.uk/api/auth/signup \
  -H "Content-Type: application/json" \
  -d '{
    "username": "student123",
    "password": "mySecurePassword",
    "confirmPassword": "mySecurePassword"
  }'

Success response (200):

user

object

User information

string

User UUID

username

string

Username

token

string

JWT authentication token (valid for 7 days)

{
  "user": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "username": "student123"
  },
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiI1NTBlODQwMC1lMjliLTQxZDQtYTcxNi00NDY2NTU0NDAwMDAiLCJ1c2VybmFtZSI6InN0dWRlbnQxMjMiLCJpYXQiOjE3MDk1NjQwMDAsImV4cCI6MTcxMDE2ODgwMH0.abc123def456"
}

Error responses:

Status	Error	Cause
`400`	`"Username and password are required"`	Missing required fields
`400`	`"Passwords do not match"`	Password confirmation doesn’t match
`400`	`"Password must be at least 6 characters"`	Password too short
`400`	`"Username already exists"`	Username taken
`400`	`"Username can only contain..."`	Invalid username format
`429`	`"Too many authentication attempts"`	Rate limit exceeded (5 attempts per 15 minutes)

Usernames are sanitized to allow only alphanumeric characters, underscores, and hyphens. The username is case-sensitive.

Log In

Authenticate with existing credentials:

POST /api/auth/login

Request body:

username

string

required

Your username

password

string

required

Your password

Example request:

curl -X POST https://api.inspir.uk/api/auth/login \
  -H "Content-Type: application/json" \
  -d '{
    "username": "student123",
    "password": "mySecurePassword"
  }'

Success response (200):

user

object

User information

string

User UUID

username

string

Username

token

string

JWT authentication token (valid for 7 days)

{
  "user": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "username": "student123"
  },
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Error responses:

Status	Error	Cause
`400`	`"Username and password are required"`	Missing required fields
`401`	`"Invalid username or password"`	Incorrect credentials
`429`	`"Too many authentication attempts"`	Rate limit exceeded

For security, the API returns the same error message whether the username doesn’t exist or the password is incorrect.

Using Your Token

Authorization Header

Include the JWT token in the Authorization header using the Bearer scheme:

Authorization: Bearer YOUR_JWT_TOKEN

Example:

curl -X GET https://api.inspir.uk/api/quiz/history \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."

Token Structure

JWT tokens contain encoded user information:

{
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "username": "student123",
  "iat": 1709564000,
  "exp": 1710168800
}

userId

string

User’s unique identifier (UUID)

username

string

User’s username

iat

number

Issued at (Unix timestamp)

exp

number

Expiration time (Unix timestamp, 7 days from issuance)

Token Validation

The server validates tokens using the middleware in backend/middleware/auth.js:7:

Checks for Authorization header with Bearer prefix
Extracts and verifies JWT signature
Decodes user ID from token payload
Queries database to ensure user still exists
Attaches user object to request: req.user

Authentication middleware implementation:

// From backend/middleware/auth.js
export async function authenticateUser(req, res, next) {
  const authHeader = req.headers.authorization;
  
  if (!authHeader || !authHeader.startsWith('Bearer ')) {
    return res.status(401).json({
      error: 'No authorization token provided'
    });
  }
  
  const token = authHeader.substring(7);
  const decoded = jwt.verify(token, JWT_SECRET);
  
  // Fetch user from database
  const { data: users, error } = await supabase
    .from('users')
    .select('id, username, created_at')
    .eq('id', decoded.userId)
    .limit(1);
  
  if (error || !users || users.length === 0) {
    return res.status(401).json({
      error: 'Invalid or expired token'
    });
  }
  
  req.user = users[0];
  next();
}

Authentication Errors

When authentication fails, the API returns 401 Unauthorized:

Missing Token

Request without Authorization header:

curl -X GET https://api.inspir.uk/api/quiz/history

Response (401):

{
  "error": "No authorization token provided"
}

Invalid Token Format

Malformed or corrupted JWT:

curl -X GET https://api.inspir.uk/api/quiz/history \
  -H "Authorization: Bearer invalid.token.here"

Response (401):

{
  "error": "Invalid token"
}

Expired Token

Token older than 7 days:

curl -X GET https://api.inspir.uk/api/quiz/history \
  -H "Authorization: Bearer eyJhbGciOi...[expired]..."

Response (401):

{
  "error": "Token expired"
}

User Not Found

Valid token but user deleted from database: Response (401):

{
  "error": "Invalid or expired token"
}

Token Refresh

Tokens are valid for 7 days. There is currently no token refresh endpoint. To get a new token:

Log in again with username and password
Replace the old token with the new one in your client

Best practice: Store tokens securely (e.g., in httpOnly cookies or secure storage). Never expose tokens in URLs or client-side JavaScript logs.

Optional Authentication

Some endpoints work for both guests and authenticated users. These use the optionalAuth middleware (backend/middleware/auth.js:59): Endpoints with optional authentication:

POST /api/quiz/generate - Generate quizzes
POST /api/quiz/submit - Submit quiz answers
GET /api/quiz/:id - View specific quiz
POST /api/quiz/shared/:shareToken/submit - Submit shared quiz

Behavior:

Without token: Request proceeds as guest user
With valid token: req.user is populated with user data
With invalid token: Request proceeds as guest (no error)

Example - Generate quiz as guest:

curl -X POST https://api.inspir.uk/api/quiz/generate \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Photosynthesis is the process...",
    "sourceName": "Biology Notes"
  }'

Quiz generates successfully but won’t be saved to history. Example - Generate quiz as authenticated user:

curl -X POST https://api.inspir.uk/api/quiz/generate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer eyJhbGci..." \
  -d '{
    "content": "Photosynthesis is the process...",
    "sourceName": "Biology Notes"
  }'

Quiz generates and saves to user’s history.

Required Authentication

Endpoints that require authentication will return 401 if no valid token is provided: Protected endpoints:

GET /api/auth/me - Get current user
GET /api/quiz/history - Get quiz history
POST /api/quiz/:quizId/share - Share a quiz
GET /api/quiz/:quizId/attempts - View quiz statistics
GET /api/streaks - View study streaks
User profile and settings endpoints

Example - Access protected endpoint without token:

curl -X GET https://api.inspir.uk/api/quiz/history

Response (401):

{
  "error": "No authorization token provided"
}

Get Current User

Verify authentication and retrieve current user information:

GET /api/auth/me

Headers:

Authorization

string

required

Bearer token

Example request:

curl -X GET https://api.inspir.uk/api/auth/me \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."

Success response (200):

user

object

Current user information

string

User UUID

username

string

Username

created_at

string

Account creation timestamp (ISO 8601)

{
  "user": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "username": "student123",
    "created_at": "2024-03-01T10:30:00.000Z"
  }
}

Error responses:

Status	Error	Cause
`401`	`"No authorization token provided"`	Missing Authorization header
`401`	`"Invalid token"`	Malformed JWT
`401`	`"Token expired"`	Token older than 7 days
`401`	`"Invalid or expired token"`	User not found in database
`401`	`"Not authenticated"`	Generic authentication failure

Logout

Log out from the current session:

POST /api/auth/logout

Example request:

curl -X POST https://api.inspir.uk/api/auth/logout

Success response (200):

{
  "message": "Logged out successfully"
}

Since authentication is JWT-based and stateless, logout is primarily handled client-side by removing the stored token. The server endpoint exists for consistency but doesn’t invalidate the token server-side. The token remains technically valid until expiration (7 days).

Security Best Practices

Store tokens securely

Use httpOnly cookies for web applications
Use secure storage mechanisms in mobile apps
Never store tokens in localStorage if XSS is a concern
Never expose tokens in URLs or logs

Handle token expiration gracefully

Monitor for 401 responses indicating expired tokens
Prompt users to re-authenticate when tokens expire
Consider implementing token refresh before implementing auto-re-login

Use HTTPS in production

Always use HTTPS to prevent token interception
The production API enforces HTTPS
Development environments (localhost) can use HTTP

Respect rate limits

Authentication endpoints are limited to 5 attempts per 15 minutes
Implement exponential backoff for retry logic
Cache tokens instead of requesting new ones on every API call

Example: Complete Authentication Flow

Here’s a complete example of signing up, authenticating, and making authenticated requests:

// 1. Sign up
const signupResponse = await fetch('https://api.inspir.uk/api/auth/signup', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    username: 'student123',
    password: 'mySecurePassword',
    confirmPassword: 'mySecurePassword'
  })
});

const { user, token } = await signupResponse.json();

// 2. Store token securely
localStorage.setItem('auth_token', token); // Or use httpOnly cookie

// 3. Make authenticated requests
const quizHistoryResponse = await fetch('https://api.inspir.uk/api/quiz/history', {
  headers: {
    'Authorization': `Bearer ${token}`
  }
});

const quizHistory = await quizHistoryResponse.json();

// 4. Handle authentication errors
if (quizHistoryResponse.status === 401) {
  // Token expired or invalid - redirect to login
  localStorage.removeItem('auth_token');
  window.location.href = '/login';
}

// 5. Logout
await fetch('https://api.inspir.uk/api/auth/logout', { method: 'POST' });
localStorage.removeItem('auth_token');

Overview

Endpoints

Authentication

Overview

Authentication Types

Public

Optional Auth

Required Auth

Getting a Token

Log In

Using Your Token

Authorization Header

Token Structure

Token Validation

Authentication Errors

Missing Token

Invalid Token Format

Expired Token

User Not Found

Token Refresh

Optional Authentication

Required Authentication

Get Current User

Logout

Security Best Practices

Example: Complete Authentication Flow

Next Steps

Quiz API

Study Tools

Build docs developers (and LLMs) love

Overview

Endpoints

​Overview

​Authentication Types

Public

Optional Auth

Required Auth

​Getting a Token

​Sign Up

​Log In

​Using Your Token

​Authorization Header

​Token Structure

​Token Validation

​Authentication Errors

​Missing Token

​Invalid Token Format

​Expired Token

​User Not Found

​Token Refresh

​Optional Authentication

​Required Authentication

​Get Current User

​Logout

​Security Best Practices

​Example: Complete Authentication Flow

​Next Steps

Quiz API

Study Tools

Build docs developers (and LLMs) love

Overview

Authentication Types

Getting a Token

Sign Up

Log In

Using Your Token

Authorization Header

Token Structure

Token Validation

Authentication Errors

Missing Token

Invalid Token Format

Expired Token

User Not Found

Token Refresh

Optional Authentication

Required Authentication

Get Current User

Logout

Security Best Practices

Example: Complete Authentication Flow

Next Steps