Does the JWT decoder verify signatures?
No. It only decodes header and payload JSON. Signature verification must happen in trusted application code.
API & Auth Tools
API and Auth Tools for Requests, Headers, cURL, and JWTs
API debugging is rarely about one value. A response includes a status code, headers, body, authentication context, and often a request example that someone copied from a terminal or browser. The API and Auth category brings together small tools that make those pieces easier to inspect without sending requests from the page.
JWT decoding helps you read token headers and payload claims while remembering that decoding is not verification. The cURL formatter turns dense request examples into a cleaner breakdown of method, URL, headers, and body. The HTTP headers parser converts raw copied headers into structured JSON so caching, rate limits, CORS, cookies, and tracing values are easier to review.
These tools are especially useful when troubleshooting authentication flows, support tickets, docs examples, webhook integrations, and client-server bugs. They are intentionally lightweight and browser-based: paste text, inspect it, copy the result, and move on.
Tools
Available in this category
Existing URLs remain active, and new tools are organized under clean category paths.
JWT Decoder
Decode JWT header and payload JSON in your browser without verifying the token signature.
Open toolcURL Formatter
Format basic cURL commands into readable method, URL, headers, body, and multi-line output.
Open toolHTTP Headers Parser
Parse raw HTTP response or request headers into readable JSON and grouped header values.
Open toolUse cases
Decode JWT headers and payloads during auth debugging.
Clean up cURL examples copied from DevTools or docs.
Parse raw HTTP headers into structured JSON.
Inspect API metadata without making a network request.
Related guides
8 min read
What is JWT and how to decode it
JWTs are common in authentication. Learn what the three sections mean and why decoding is not verification.
8 min read
How to read HTTP headers
HTTP headers carry metadata that explains how an API response should be parsed, cached, authenticated, and traced.
8 min read
What is cURL used for
cURL is a command-line tool for making network requests, testing APIs, and sharing reproducible request examples.
8 min read
Best practices for working with API responses
API responses are easier to debug when you validate syntax, format payloads, inspect errors, and compare changes deliberately.
9 min read
What is JWT authentication
JWT authentication uses signed tokens to carry claims between a client and a server, but decoding a token is not verification.
9 min read
JWT header, payload, and signature explained
A JWT has three dot-separated parts: metadata in the header, claims in the payload, and a signature used for verification.
9 min read
Common JWT security mistakes
JWTs are easy to decode, but safe JWT authentication depends on verification, expiration, storage, and careful claim design.
9 min read
REST API basics for beginners
REST APIs organize operations around resources, HTTP methods, status codes, headers, and structured request or response bodies.
9 min read
HTTP request vs response
A request is what the client sends; a response is what the server returns. Debugging APIs means reading both sides.
9 min read
How bearer tokens work
A bearer token grants access to whoever presents it, which makes storage, lifetime, and redaction important.
9 min read
API pagination explained
Pagination splits large result sets into smaller responses using page numbers, cursors, limits, offsets, or continuation tokens.
9 min read
Common HTTP methods
HTTP methods communicate the intended action: read, create, replace, modify, delete, inspect, or negotiate.
9 min read
What is CORS
CORS is a browser security mechanism that controls which origins can read responses from another origin.
9 min read
Content-Type explained
Content-Type declares the media type of a body, such as application/json, text/html, text/csv, or multipart/form-data.
9 min read
Cookies vs localStorage
Cookies can be sent automatically with requests and support security flags; localStorage is script-readable browser storage.
9 min read
HTTP caching basics
HTTP caching controls how browsers and CDNs reuse responses, revalidate them, or fetch fresh copies.
9 min read
Basic API security practices
Secure APIs validate input, authenticate callers, authorize actions, limit abuse, and avoid leaking secrets in logs or responses.
9 min read
Safe handling of tokens online
Tokens should be treated like temporary passwords: inspect carefully, redact aggressively, and avoid sharing live values.
FAQ
Does the cURL formatter send requests?
No. It only parses and formats pasted command text.
Should I paste live tokens?
Avoid pasting live secrets into online tools. Use redacted test values when possible.
Can headers reveal private data?
Yes. Cookies, Authorization headers, and internal tracing values should be redacted before sharing.