Jwt Decoder vs Jwt Generator

Our JWT Decoder and JWT Generator are companion tools that cover both sides of the JWT workflow — inspecting existing tokens and creating new ones for testing. Together they provide a complete browser-based JWT development toolkit.

Overview

JWT Decoder takes an encoded JWT string and splits it into its three parts: header, payload, and signature. It displays the algorithm, all claims (sub, iss, exp, iat, and custom claims), and checks expiration status. No secret key is needed for decoding. JWT Generator lets you build a JWT from scratch by specifying the header algorithm, payload claims, expiration time, and signing secret. It produces a signed token string that can be used for API testing and authentication debugging.

Key Differences

Direction: JWT Decoder works from token to readable claims (decoding). JWT Generator works from claims to token (encoding and signing). Secret key requirement: JWT Decoder does not need the signing secret — JWT payloads are Base64-encoded, not encrypted. JWT Generator requires a secret key to produce a valid signature. Use case: JWT Decoder is for debugging — "what is in this token and is it expired?" JWT Generator is for testing — "I need a token with these claims to test my API endpoint." Validation: JWT Decoder shows whether a token is expired but cannot verify the signature without the secret. JWT Generator produces tokens with valid signatures for the specified algorithm and secret.

Pricing

Both tools are completely free, process everything in your browser, and never transmit your tokens or secrets.

Verdict

Use JWT Decoder when you need to quickly inspect a token from an API response, cookie, or authorization header. Use JWT Generator when you need to create test tokens for API development. Both tools keep your data local — tokens and secrets never leave your browser.