JWT Decoder & Validator
Inspect JSON Web Tokens with instant header/payload decoding, signature awareness, claim validation, and security warnings — all in-browser.
How It Works
Paste Your JWT
Drop in access tokens from dev, staging, or production environments. The decoder validates the three-part JWT structure before parsing.
Decode Header & Payload
Toggle pretty-printed JSON, inspect raw Base64 segments, and review algorithms, token type, issuer, subject, audience, and custom claims.
Check Expiry & Warnings
See issued-at/expiry timestamps converted to ISO time, plus flags for expired tokens, missing claims, or absent signatures.
Export Findings Securely
Copy decoded sections, download analysis, or store runs in tool history for debugging incident reports — without ever sending tokens to a server.
Problems It Solves
Problem
Debugging authentication issues is slow when you cannot quickly visualize JWT claims during incident response.
Solution
Decode tokens instantly with formatted JSON and metadata so developers can pinpoint claim mismatches or audience errors immediately.
Problem
Security reviews require verifying expiry dates, algorithms, and presence of critical claims without risking data exposure.
Solution
All decoding happens locally with expiry checks, algorithm visibility, and warnings when essential claims are missing.
Problem
Tokens from multiple environments need comparison, but raw Base64 segments make diffs cumbersome.
Solution
Switch between raw and formatted views, then export structured summaries for documentation or automated diffing.
Why Choose This Tool
Client-Side Privacy
Tokens stay on your machine, keeping access credentials, PII claims, and signed metadata out of third-party services.
Actionable Metadata
Surface algorithms, issuer, subject, audience, signature presence, and expiration flags to support audits and regression testing.
Flexible Views
Toggle formatted or raw output for both header and payload, making it easy to copy segments into Postman, curl scripts, or docs.
Developer-Friendly UX
Keyboard shortcuts, history tracking, and copy/download controls help auth engineers troubleshoot tokens faster.
Frequently Asked Questions
What is a JWT?
Can this tool verify JWT signatures?
What are the three parts of a JWT?
What are JWT claims?
Is it safe to decode JWTs online?
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