Security Tools

JWT Generator

Generate JSON Web Tokens with custom claims and multiple algorithms

Algorithm

Key ID (kid)

Secret Key

Standard Claims

Claims: 3 | Size: 0 B

iss

sub

aud

exp

nbf

iat

jti

Expiration

Or pick expiration date/time

Custom Header Fields

Custom Claims

About

Generates JSON Web Tokens with configurable algorithm selection (HS256, HS384, HS512, or none), a header/payload builder with standard claim auto-completion, an expiry date/time picker, and a secret input field. Displays a live token preview with color-coded sections before final generation.

Testing JWT-based authentication requires valid tokens with specific claims, expiry times, and algorithms. Eliminates manual token construction and base64 encoding, providing a visual builder for rapid prototyping and testing.

Who should use this tool?

Backend and API developers testing JWT authentication flows, security engineers creating test tokens, and developers integrating with JWT-based services during development.

Common use cases

Generate test JWTs with specific claims for unit testing authentication middleware
Create JWTs with controlled expiry times for testing token refresh logic
Build tokens with different algorithms (HS256/HS384/HS512) to test algorithm compatibility
Generate JWTs with custom claims for integration testing of authorization systems
Create tokens with "none" algorithm to test security validation in development environments
Generate signed JWTs for load testing JWT-dependent services with controlled payloads

How to Use

Select the signing algorithm from the dropdown (HS256, HS384, HS512, or none for unsigned tokens)

Use the payload builder to add claims: select standard claims (iss, sub, aud, exp, nbf, iat, jti) or add custom key-value pairs

Set the expiry time using the date/time picker; the tool automatically calculates the exp claim epoch value

Enter a secret key in the secret input field; minimum length requirements vary by algorithm strength

Review the live token preview showing the three color-coded sections as you build the payload

Click "Generate" to finalize; copy the token or download it; use "Regenerate" to update with new settings

Examples

Settings: alg=HS256, secret=mysecret, claims: {sub:"123",name:"Alice",exp:2025-01-01T00:00Z} -> Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjMiLCJuYW1lIjoiQWxpY2UiLCJleHAiOjE3Mzc2MDAwMDB9.signature

Settings: alg=none, claims: {role:"admin"} -> Output: eyJhbGciOiJub25lIiwidHlwIjoiSldUIn0.eyJyb2xlIjoiYWRtaW4ifQ.

Best Practices

Use strong secrets (32+ characters) for HS256 to prevent brute-force attacks on JWT signatures
Set realistic expiry times matching your production token lifetime (usually 15-60 minutes for access tokens)
Include only necessary claims to keep the token size small and avoid exposing sensitive data
Use the "none" algorithm only for testing scenarios where signature validation is deliberately skipped
Generate multiple tokens with different claims to thoroughly test authorization logic edge cases

Common Mistakes

Using weak secrets like "secret" or "password" which are easily brute-forced to forge signatures
Setting extremely long expiry times (years) which creates security tokens that never expire
Including sensitive data (passwords, PII) in the payload which is base64-encoded, not encrypted
Using HS256 with secrets that don't meet minimum length requirements, weakening the signature
Forgetting that unsigned tokens (alg:none) should never be accepted in production environments

FAQ

Can I generate tokens with asymmetric algorithms (RS256/ES256)? This tool supports symmetric HMAC algorithms (HS256/384/512); for asymmetric keys, use a dedicated JWT library.

How is the expiry time calculated? The exp claim is set as the Unix epoch timestamp of the selected date/time in UTC.

Does the tool store the generated token or secret? No, all generation happens client-side; nothing is persisted or transmitted.

Can I generate multiple tokens at once? The tool generates one token per configuration; use the "Regenerate" button after changing claims or settings.

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JWT Generator

Generate JSON Web Tokens with custom claims and multiple algorithms

Algorithm

Key ID (kid)

Secret Key

Standard Claims

Claims: 3 | Size: 0 B

iss

sub

aud

exp

nbf

iat

jti

Expiration

Or pick expiration date/time

Custom Header Fields

Custom Claims

About

Who should use this tool?

Backend and API developers testing JWT authentication flows, security engineers creating test tokens, and developers integrating with JWT-based services during development.

Common use cases

Generate test JWTs with specific claims for unit testing authentication middleware
Create JWTs with controlled expiry times for testing token refresh logic
Build tokens with different algorithms (HS256/HS384/HS512) to test algorithm compatibility
Generate JWTs with custom claims for integration testing of authorization systems
Create tokens with "none" algorithm to test security validation in development environments
Generate signed JWTs for load testing JWT-dependent services with controlled payloads

How to Use

Select the signing algorithm from the dropdown (HS256, HS384, HS512, or none for unsigned tokens)

Use the payload builder to add claims: select standard claims (iss, sub, aud, exp, nbf, iat, jti) or add custom key-value pairs

Set the expiry time using the date/time picker; the tool automatically calculates the exp claim epoch value

Enter a secret key in the secret input field; minimum length requirements vary by algorithm strength

Review the live token preview showing the three color-coded sections as you build the payload

Click "Generate" to finalize; copy the token or download it; use "Regenerate" to update with new settings

Examples

Settings: alg=HS256, secret=mysecret, claims: {sub:"123",name:"Alice",exp:2025-01-01T00:00Z} -> Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjMiLCJuYW1lIjoiQWxpY2UiLCJleHAiOjE3Mzc2MDAwMDB9.signature

Settings: alg=none, claims: {role:"admin"} -> Output: eyJhbGciOiJub25lIiwidHlwIjoiSldUIn0.eyJyb2xlIjoiYWRtaW4ifQ.

Best Practices

Use strong secrets (32+ characters) for HS256 to prevent brute-force attacks on JWT signatures

Set realistic expiry times matching your production token lifetime (usually 15-60 minutes for access tokens)

Include only necessary claims to keep the token size small and avoid exposing sensitive data

Use the "none" algorithm only for testing scenarios where signature validation is deliberately skipped

Generate multiple tokens with different claims to thoroughly test authorization logic edge cases

Common Mistakes

Using weak secrets like "secret" or "password" which are easily brute-forced to forge signatures

Setting extremely long expiry times (years) which creates security tokens that never expire

Including sensitive data (passwords, PII) in the payload which is base64-encoded, not encrypted

Using HS256 with secrets that don't meet minimum length requirements, weakening the signature

Forgetting that unsigned tokens (alg:none) should never be accepted in production environments

FAQ

Can I generate tokens with asymmetric algorithms (RS256/ES256)? This tool supports symmetric HMAC algorithms (HS256/384/512); for asymmetric keys, use a dedicated JWT library.

How is the expiry time calculated? The exp claim is set as the Unix epoch timestamp of the selected date/time in UTC.

Does the tool store the generated token or secret? No, all generation happens client-side; nothing is persisted or transmitted.

Can I generate multiple tokens at once? The tool generates one token per configuration; use the "Regenerate" button after changing claims or settings.

JWT Generator

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Security Tools

JWT Decoder

Hash Generator

JSON Schema Generator

TOTP Generator

Popular Tools

JSON Formatter

Base64 Encoder/Decoder

SQL Formatter

Learning Resources

Share

JWT Generator

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Security Tools

JWT Decoder

Hash Generator

JSON Schema Generator

TOTP Generator

Popular Tools

JSON Formatter

Base64 Encoder/Decoder

SQL Formatter

Learning Resources

Share