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JWT Decoder

Decode and analyze JWT tokens online free

JWT Token(s)

About

Decodes JSON Web Tokens with color-coded sections (header/payload/signature) for visual parsing. Automatically decodes standard timestamp claims (exp, iat, nbf) into human-readable dates, supports signature verification with secret/private key, and provides an expiry countdown timer with token analysis suggestions.

JWTs are opaque strings that encode important security information; manually base64-decoding and inspecting each section is tedious and error-prone. Provides instant visual decoding, security analysis, and expiry monitoring in one interface.

Who should use this tool?

Backend developers, security engineers, API developers, and anyone working with JWT-based authentication or authorization systems.

Common use cases

Debug authentication issues by inspecting JWT payloads and signature validity
Verify JWT expiry times and decode timestamps during token-based auth implementation
Analyze JWT header algorithms and security characteristics for security audits
Validate JWTs received from third-party SSO providers during integration
Decode and inspect refresh tokens and access tokens during OAuth2/OIDC implementation
Test JWT signature validity with shared secrets during development and testing

How to Use

Paste your JWT string into the input field; the tool automatically splits and color-codes the three sections

Review the header section (pink) showing algorithm type (HS256/RS256/etc) and token type (JWT)

Inspect the payload section (blue) with all claims auto-decoded; timestamp claims (exp, iat, nbf) show both raw epoch and human-readable date

Scroll to the signature section (green) showing the raw signature and signature verification options

Enter the secret or public key in the verification field and click "Verify" to check signature validity; results show Valid or Invalid

Monitor the expiry countdown timer that shows remaining seconds/minutes/hours until token expiration

Examples

Input: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkFsaWNlIiwiZXhwIjoxNzA0MDYwODAwfQ.abc123signature -> Output: Header: {alg:HS256,typ:JWT} | Payload: {sub:1234567890,name:Alice,exp:2024-01-01T00:00:00Z} | Expiry: Expired 2 years ago

Input: JWT with exp claim of 9999999999 -> Output: Payload shows exp:9999999999 (November 20, 2286) | Countdown: 262 years remaining

Best Practices

Always verify the signature when decoding JWTs from untrusted sources, not just the payload content
Check the algorithm in the header; reject tokens using "none" algorithm unless explicitly intended
Use the expiry countdown to monitor token lifetimes during auth flow testing and debugging
Compare decoded claims against expected values from your auth provider documentation
Never share decoded token contents or secrets when pasting in shared/screencast environments

Common Mistakes

Trusting the payload content without verifying the signature - JWTs can be decoded by anyone
Not checking the algorithm field and accepting tokens with "none" algorithm (security vulnerability)
Assuming all timestamps are in seconds; some implementations use milliseconds which the tool flags
Sharing decoded JWTs containing sensitive claims like email, user IDs, or roles in public forums
Forgetting that a valid signature only proves integrity, not that the token has been authorized or is still valid

FAQ

Does it support JWE (encrypted) tokens? No, this tool handles JWS (signed) tokens only, not encrypted JWEs.

Can it verify JWTs signed with RS256 or ES256? Yes, if you provide the corresponding public key for asymmetric algorithms.

How does it handle custom claims? All custom claims are displayed as-is in the payload section with their raw values.

Does it store or transmit the token anywhere? No, all decoding happens client-side in the browser; no data is sent to any server.

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Learning Resources

Dive deeper with our comprehensive guides and tutorials.

JWT Decoder - Beginner's Guide

5 min read

JWT Decoder Advanced Techniques

8 min read

About

Who should use this tool?

Backend developers, security engineers, API developers, and anyone working with JWT-based authentication or authorization systems.

Common use cases

Debug authentication issues by inspecting JWT payloads and signature validity
Verify JWT expiry times and decode timestamps during token-based auth implementation
Analyze JWT header algorithms and security characteristics for security audits
Validate JWTs received from third-party SSO providers during integration
Decode and inspect refresh tokens and access tokens during OAuth2/OIDC implementation
Test JWT signature validity with shared secrets during development and testing

How to Use

Paste your JWT string into the input field; the tool automatically splits and color-codes the three sections

Review the header section (pink) showing algorithm type (HS256/RS256/etc) and token type (JWT)

Inspect the payload section (blue) with all claims auto-decoded; timestamp claims (exp, iat, nbf) show both raw epoch and human-readable date

Scroll to the signature section (green) showing the raw signature and signature verification options

Enter the secret or public key in the verification field and click "Verify" to check signature validity; results show Valid or Invalid

Monitor the expiry countdown timer that shows remaining seconds/minutes/hours until token expiration

Examples

Input: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkFsaWNlIiwiZXhwIjoxNzA0MDYwODAwfQ.abc123signature -> Output: Header: {alg:HS256,typ:JWT} | Payload: {sub:1234567890,name:Alice,exp:2024-01-01T00:00:00Z} | Expiry: Expired 2 years ago

Input: JWT with exp claim of 9999999999 -> Output: Payload shows exp:9999999999 (November 20, 2286) | Countdown: 262 years remaining

Best Practices

Always verify the signature when decoding JWTs from untrusted sources, not just the payload content

Check the algorithm in the header; reject tokens using "none" algorithm unless explicitly intended

Use the expiry countdown to monitor token lifetimes during auth flow testing and debugging

Compare decoded claims against expected values from your auth provider documentation

Never share decoded token contents or secrets when pasting in shared/screencast environments

Common Mistakes

Trusting the payload content without verifying the signature - JWTs can be decoded by anyone

Not checking the algorithm field and accepting tokens with "none" algorithm (security vulnerability)

Assuming all timestamps are in seconds; some implementations use milliseconds which the tool flags

Sharing decoded JWTs containing sensitive claims like email, user IDs, or roles in public forums

Forgetting that a valid signature only proves integrity, not that the token has been authorized or is still valid

FAQ

Does it support JWE (encrypted) tokens? No, this tool handles JWS (signed) tokens only, not encrypted JWEs.

Can it verify JWTs signed with RS256 or ES256? Yes, if you provide the corresponding public key for asymmetric algorithms.

How does it handle custom claims? All custom claims are displayed as-is in the payload section with their raw values.

Does it store or transmit the token anywhere? No, all decoding happens client-side in the browser; no data is sent to any server.

JWT Decoder

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Security Tools

Hash Generator

JWT Generator

JSON Schema Generator

TOTP Generator

Popular Tools

JSON Formatter

Base64 Encoder/Decoder

SQL Formatter

Learning Resources

Share

JWT Decoder

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Security Tools

Hash Generator

JWT Generator

JSON Schema Generator

TOTP Generator

Popular Tools

JSON Formatter

Base64 Encoder/Decoder

SQL Formatter

Learning Resources

Share