API debugging
Decode access tokens to inspect issuer, subject, audience, roles, scopes, and expiration values during development.
Token Inspection Utility
JWT Decoder, Encoder, and HS256 Verification Tool
Decode JWT headers and payloads, inspect exp, iat, and nbf timing claims, encode HS256 tokens, and verify signatures in one private browser workspace. It is useful for debugging auth flows, API integrations, and token issues without leaving the page.
🔍 Decode JWT✅ Verify HS256⏱ Check expiration
JWT Decoder and Encoder
Paste a token to decode it, edit payload JSON, encode HS256 tokens, or verify a token signature with a secret key.
JWT Decoder and Encoder
Paste a token to decode it, edit payload JSON, encode HS256 tokens, or verify a token signature with a secret key.
Result
Token status, timing claims, signature check, and security notes appear here.
Common Ways People Use This Tool
QA verification
Check whether a test token is expired, not active yet, or signed with the expected HS256 secret.
Security review
Spot risky payload data, missing timing claims, or readable sensitive information before tokens reach production.
Worked Examples
Example 1: Decode a login token
Paste a JWT and review the payload JSON. Check exp to confirm when the token should stop being accepted.
Example 2: Verify HS256
Paste the token, enter the expected secret key, and run Verify to compare the recalculated signature with the token signature.
How This JWT Tool Works
The tool splits the token into header, payload, and signature, decodes the Base64URL sections, and optionally verifies HS256 signatures.
When you paste a JWT into the page, the tool separates the three token parts and decodes the readable sections so you can inspect claims such as issuer, subject, audience, roles, expiration, and custom metadata. That makes it useful for debugging authentication flows, checking API integrations, reviewing session behavior, and understanding what a token is actually carrying.
JWT header and payload sections are usually encoded, not encrypted. Anyone who holds the token can often read those claims, which is why sensitive secrets should not be placed in a standard JWT payload. Signature verification is a separate step from decoding. Decoding only shows the content, while verification checks whether the token was signed with the expected secret or key.
This browser tool supports quick HS256 testing for development and troubleshooting. Production token handling still needs strict backend validation for issuer, audience, expiration, not-before values, accepted algorithms, key rotation, revocation strategy, and safe storage rules on both the client and server side.
More Useful Security Tools
Generate tokens
Use Random Token Generator for creating secure random tokens for sessions.
Generate API keys
Use API Key Generator for random keys with prefixes and export options.
Hash data
Use SHA256 Generator for creating hashes and signatures.
JWT Safety Notes
JWTs are easy to inspect, but production token handling must be strict.
Do not place secrets, passwords, private keys, or sensitive personal data directly inside a normal JWT payload unless the token is properly encrypted with a design that fits your threat model. Standard JWT payloads are often readable by anyone who has the token, so they should usually carry claims, identifiers, and authorization metadata rather than confidential secrets.
Production systems should validate issuer, audience, expiration, not-before, accepted algorithms, signing keys, clock skew, revocation strategy, and token storage rules on the backend. Safe JWT use also depends on short lifetimes where appropriate, secure cookies or other storage decisions, refresh-token design, and clear logout or revocation handling.
This page supports searches around JWT decoder, JWT verifier, inspect JWT payload, HS256 JWT check, and JSON Web Token tool. Useful next internal links for token workflows are the Random Token Generator, API Key Generator, Encryption Tool, and the Security Tools Hub.
Frequently Asked Questions
Answers about decoding JWTs, HS256 verification, expiration claims, encrypted tokens, payload safety, and privacy.
A JWT, or JSON Web Token, is a compact token format used to transfer claims between systems.
It usually contains a header, payload, and signature separated by dots.
Yes. The header and payload of a standard JWT can usually be decoded without the secret key because they are Base64URL encoded.
The secret key is only needed for signature generation and verification in HS256.
Yes. This tool can verify HS256 signatures when you provide the correct secret key.
The verification result will show whether the signature matches or not.
The exp claim means expiration time. It tells you when the token should no longer be accepted.
This tool converts it into a readable date and also shows whether the token is still valid or expired.
iat means issued at, which tells you when the token was created.
nbf means not before, which tells you the earliest time the token should be accepted.
No. This tool is for standard JWT inspection and HS256 verification. Encrypted token formats such as JWE require different handling.
No. JWT payloads are usually readable by anyone who has the token. Sensitive secrets should not be stored directly in the payload.
No. The tool works in your browser, which helps keep the token data local on your device.