JWT Compare Tool – Visual Diff & Security Analysis
Compare two JWT tokens side by side. Instantly spot differences in claims, headers, and security posture. Perfect for debugging, audits, and migrations.
Differences
- No differences
Token 1
Token 2
How to Use the JWT Compare Tool
- Paste or enter two JWTs in the input cards above.
- See a visual summary of differences in header, payload, and signature.
- Review decoded details, claims, and security analysis for each token.
- Use this tool to debug, audit, or verify changes between tokens.
What is a JWT Compare Tool?
The JWT Compare Tool lets you analyze two JSON Web Tokens side-by-side. Instantly spot differences in claims, headers, signatures, and security posture.
How does it work?
- Paste two JWTs to compare their structure and claims.
- See a visual diff of header, payload, and signature.
- Get security analysis for each token, including algorithm, expiration, and best practices.
JWT Fundamentals
- What is a JWT? A compact, URL-safe token format for securely transmitting information between parties as a JSON object.
- JWT Structure: Consists of a header, payload, and signature. Each part is Base64URL encoded and separated by dots.
- Security Best Practices: Always validate both tokens, check for expiration, and compare claims carefully.
- Common Claims:
iss(issuer),sub(subject),aud(audience),exp(expiration),nbf(not before),iat(issued at),jti(JWT ID). - JWT vs Other Tokens: JWTs are stateless and self-contained, unlike session tokens or API keys.
- Troubleshooting: Use this tool to debug authentication issues, verify token changes, and ensure security compliance.
Frequently Asked Questions
What types of differences does the compare tool detect?
Our tool detects differences in headers (algorithm, type), payload claims (added, removed, or changed values), expiration times, issuers, audiences, and security configurations. It provides a detailed breakdown of each difference with explanations.
Why would I need to compare JWT tokens?
Token comparison helps debug authentication issues, verify token changes during updates, validate token generation consistency across environments, audit security improvements, and ensure backward compatibility during system migrations.
How does the similarity percentage work?
Similarity percentage compares all claims and header fields between tokens. It's calculated as (matching fields / total unique fields) × 100. Identical tokens show 100%, completely different tokens show 0%. This helps quickly assess how similar or different two tokens are.
Can I compare tokens with different algorithms?
Yes! You can compare any two valid JWTs regardless of their algorithms. The tool will highlight algorithm differences and explain the security implications. This is useful when migrating from one algorithm to another (e.g., HS256 to RS256).
What should I do if tokens show major differences?
Major differences might indicate configuration issues, security problems, or intentional changes. Review each difference carefully - some might be expected (like different expiration times), while others might need attention (like changed issuers or missing security claims).