JWT Validate

Verify a JWT's signature and validate its claims. Confirms the token is authentic, unexpired, and structurally sound.

Validation Order

Check in this order. Stop and report at the first failure.

1. Structure

• Exactly 3 dot-separated parts, each valid base64url
• Header and payload parse as valid JSON
• Header contains alg; alg is not none (unless explicitly expected)

2. Claims