Verify JWT Locally

Verify a session JWT locally

Verify a session JWT locally using the ES256 algorithm and a public key.

Verification Process

To verify a JWT locally, you'll need:

1. The JWT token to verify

2. The public key in PEM format (base64 encoded)

Parameters

{
  token: string,      // The JWT to verify
  publicKey: string   // Base64 encoded public key (must be decoded to UTF-8 before use)
}

Example Usage

try {
    const decodedToken = jwt.verify(token, Buffer.from(base64PublicKey, 'base64').toString('utf-8'), { algorithms: ['ES256'] });
    // JWT is valid, decodedToken contains the payload
} catch (error) {
    // JWT verification failed
    console.error(error.message);
}

Error Cases

Verification will throw an error if:

• The JWT format is invalid

• The signature is invalid

• The token has expired (due to logout for example)

• The algorithm doesn't match (must be ES256)