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Count words, chars, reading time

UPPER, lower, camelCase & more

Lorem Ipsum Generator

Generate placeholder text

Flip text chars or words

Beautify & validate JSON

Encode or decode Base64

Encode/decode URL strings

Escape HTML entities

Test regex patterns live

MD5, SHA-256, SHA-512

Color Converter

HEX, RGB, HSL, CMYK

CSS Gradient Maker

Build gradients visually

Password Generator

Cryptographically strong

Length, weight, temp, speed

Exact age in years/days

Body mass index checker

Random Number Gen

Generate random numbers

Meta Tag Generator

OG, Twitter, SEO tags

Timestamp Converter

Unix ↔ readable date

Decode JWT header & payload

Random UUID v4 in bulk

Compare two texts line by line

SEO-friendly URL slugs

Latest practical guides

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Text Title Case vs Sentence Case Know which style to use in headings, buttons, filenames and code. Developer URL Encoding Query Parameters Fix broken links with spaces, ampersands, hashes and Unicode. Math Unit Conversion Formulas Convert metric, imperial, temperature and speed without guessing. Health BMI Formula Metric and Imperial Calculate adult BMI and understand why it is only a screening number. Finance Loan Payment Formula Estimate monthly payment, total interest and full repayment cost. Developer Convert JSON to CSV Prepare JSON arrays for Excel, Google Sheets and database imports.

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Free Online Tools for Developers & Productivity

ToolZone is a curated collection of 28 free online tools for developers, designers, writers, and everyday productivity. Every tool runs entirely in your browser — no signup, no uploads. Your tool input never leaves your device.

Format and validate JSON, generate strong passwords, encode and decode Base64 or URLs, test regular expressions, convert colors, build CSS gradients, calculate BMI or age, generate Lorem Ipsum, hash text with MD5 or SHA-256, and more — all from a single fast, private, dark-themed workspace.

Whether you're a developer needing quick utilities, a designer working with colors and gradients, or a writer counting words and characters, ToolZone gives you instant, low-clutter access to professional-grade web tools that work offline once loaded.

Free JWT Decoder — Inspect Header, Payload & Expiry

Paste any JSON Web Token to instantly read its header, payload claims (sub, iss, aud, iat, exp) and whether it has expired. Everything is decoded locally in your browser, so access tokens and ID tokens never leave your device — the safest way to debug authentication.

Features

Decodes header and payload with pretty-printed JSON
Shows exp / iat as readable dates plus expired or valid status
Base64URL-safe — handles real-world tokens
Runs entirely client-side, tokens are never sent anywhere

How to use

Step 1. Copy the JWT from your app, browser devtools or API response.
Step 2. Paste it into the input box.
Step 3. Read the decoded header, payload and expiry status.

Real use case: an API returns 403 and nobody knows why

A frontend developer's requests suddenly fail with 403 Forbidden, while the same endpoint works for a teammate. The only difference is the bearer token being sent.

Decoding the token shows the payload contains role: "viewer" and an exp timestamp already in the past. Two bugs surface at once: the account has the wrong role, and the client is not refreshing expired tokens. Neither is visible without reading the claims.

How JWT Decoder works

A JWT is three Base64URL-encoded segments separated by dots: header.payload.signature. The decoder splits on the dots, converts Base64URL to standard Base64 (replacing - and _, restoring padding), decodes to UTF-8 and parses the header and payload as JSON.

Standard claims are surfaced in human terms: exp and iat are Unix timestamps rendered as dates with a clear expired/valid indicator, plus iss, aud and sub when present.

Critically, decoding is not verification. The payload is merely encoded, not encrypted — anyone holding the token can read it. Only the server, using the signing secret or public key, can confirm the signature is authentic, so never trust decoded claims client-side for authorisation. Decoding happens entirely in your browser, so pasting a token here does not transmit it.

JWT Decoder vs similar tools

JWT tooling compared:

Tool	How it works	Trade-off
Server-side libraries (jose, jsonwebtoken)	Verify signature, issuer, audience and expiry.	The only correct way to trust a token — but it needs code and the key.
Online debuggers that accept your secret	Decode and verify in one page.	Pasting a production signing secret into a website is a serious risk.
ToolZone JWT Decoder	Local, read-only decoding of header, payload and expiry — no secret required or accepted.	Does not verify signatures, by design.

Frequently Asked Questions

Does this verify the JWT signature?

No. Decoding is separate from verification — the signature can only be checked with the secret or public key, which should stay on your server. Use this tool to read claims, not to trust them.

Is it safe to paste a real access token?

Decoding happens locally in your browser with no network request, so the token is not transmitted. Still, treat tokens as secrets and avoid pasting production tokens into unknown websites.

Why is my token unreadable?

A JWT has three dot-separated Base64URL parts. If the payload is encrypted (JWE) rather than signed (JWS), it cannot be decoded without the key.

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Guides worth reading

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