Security Enhancements Use Strong Signing Algorithms: Use HS256 or RS256 for JWT tokens.

Set Expiry Time (exp): Avoid long-lived tokens. Use short expiration with refresh tokens.

Use Refresh Tokens: Keep access tokens short-lived and refresh them securely.

Include Audience (aud) and Issuer (iss): Helps verify who the token is for and who issued it.

Rotate Secrets: Regularly rotate signing keys or secrets.

Use HTTPS: Always transmit tokens over secure HTTPS to prevent sniffing.

Limit Scope: Use scopes or claims to restrict access to necessary resources only.

Store Securely: Don’t store tokens in localStorage (XSS risk); prefer HTTP-only cookies. from flask_jwt_extended import JWTManager, jwt_required, create_access_token, create_refresh_token

If access token expires

@app.route('/refresh', methods=['POST']) @jwt_required(refresh=True) def refresh(): identity = get_jwt_identity() return jsonify(access_token=create_access_token(identity=identity)), 200 async function fetchWithAuth() { try { const res = await fetch('/api/data', { headers: { Authorization: Bearer ${accessToken} } }); if (res.status === 401) { // Token expired, try refresh const refreshRes = await fetch('/refresh', { method: 'POST' }); const { access_token } = await refreshRes.json(); accessToken = access_token; return fetchWithAuth(); // retry with new token } return await res.json(); } catch (err) { console.error('Fetch failed:', err); } }