JWT Inspector

JWT Inspector analyzes JSON Web Tokens used in modern APIs. It accepts a token string and returns a structured view of header, payload, and a signature status. It supports both signed (JWS) tokens and encrypted (JWE) tokens by indicating algorithm and key requirements. It also supports integration with stateless backends and token-bound microservices, and presents results in a format suitable for automated parsing.
Conceptually, the tool decodes base64url sections, parses JSON, and surfaces standard claims such as iss, sub, aud, exp, and nbf. When a key or secret is supplied, it can verify the signature using common algorithms (HS256, RS256) and report verification outcomes. It gracefully handles malformed tokens and flags non-base64url segments, and it includes clock skew tolerance for time-based checks.
Who benefits: backend engineers integrating OAuth2/OpenID Connect, security engineers auditing token flows, QA analysts validating API behavior, and incident responders diagnosing token issues. Unique value: fast, structured token insight, automated claim checks, and exportable results suitable for audits. The tool is designed for CI pipelines and API test suites, enabling consistent token analysis across environments.
Core features and use cases: decode-only view; signature verification with key input; claim validation against issuer/audience; expiration and clock skew checks; human-readable summaries; and automation-ready JSON output. Advanced mode enables claim-specific checks, configurable fail-fast policies, and metadata annotations for governance.
Examples: Given a sample token, users see header.alg and payload.iss, payload.exp values; If a mismatch is found, the tool highlights it and shows recommended remediation steps such as rotating keys or adjusting audience values. Output formats include JSON and CSV for pipelines.