Free Online Developer Tools

Format, validate, encode, and test code snippets.

A fast, searchable collection of developer utilities used daily by engineers — formatters, validators, encoders, and generators. Everything is keyboard-friendly, copy-ready, and private.

Problems developer tools solve

Pretty-printing minified JSON from API responses so it's actually readable
Decoding JWT tokens to inspect claims without leaking them to a third-party site
Testing regex patterns against sample input with live match highlighting
Generating UUIDs, hashes, and random IDs for tests and migrations
Encoding or decoding Base64 and URL-encoded strings during debugging
Formatting SQL queries pasted from logs into something reviewable

Recommended developer tools

Our most-used tools in this category — start here.

JSON Formatter

Format, validate, and minify JSON with syntax error highlighting

JWT Decoder

Decode JWT header and payload locally — tokens never leave your browser

Regex Tester

Live regex matching with capture groups and explanation

Base64 Encode/Decode

Encode and decode Base64 for strings and files

Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes client-side

Popular tools

Try our most-used tools

Merge PDF Remove Background JSON Formatter

All developer tools (22)

Popular

JSON Formatter

Format, validate, and minify JSON.

Popular

Base64 Encode/Decode

Encode and decode Base64 strings.

Popular

URL Encode/Decode

Percent-encode or decode URL strings.

JWT Decoder

Decode JSON Web Tokens locally.

Regex Tester

Test regular expressions with live matches.

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-512 hashes.

UUID Generator

Generate v4 UUIDs on demand.

Timestamp Converter

Convert Unix timestamps to dates and back.

Cron Expression Reader

Explain cron expressions in plain English.

HTML Beautifier

Format HTML with proper indentation.

CSS Beautifier

Format CSS with consistent indentation.

JavaScript Beautifier

Format JavaScript source code.

CSS Minifier

Shrink CSS for production.

JavaScript Minifier

Shrink JS for production.

HTML Minifier

Compress HTML for faster loads.

SQL Formatter

Pretty-print SQL queries.

XML Formatter

Format and validate XML.

HTML Entity Encoder

Encode and decode HTML entities.

JSON / YAML Converter

Convert JSON to YAML and back.

JSON Diff

Compare two JSON documents side-by-side.

HTTP Status Codes

Searchable reference for every HTTP status code.

User-Agent Parser

Decode any User-Agent string.

Who uses developer tools?

Backend engineers inspecting API payloads
Frontend developers debugging tokens and encoded strings
DevOps engineers formatting config files and logs
QA engineers building regex for validation rules
Students learning how encoding and hashing work
Security researchers decoding JWTs and Base64 locally

Frequently asked questions

Yes. Tools like JWT decoder and hash generators process inputs locally — nothing is sent anywhere. This is critical for production tokens, API keys, and internal payloads you can't paste into arbitrary websites.

The decoder shows the header and payload without verifying the signature. To verify, you'd need the signing secret or public key, which we deliberately don't ask for to keep the tool zero-trust.

It uses JavaScript's native regex engine (ECMAScript). That means features like lookbehinds and named groups work in modern browsers, but PCRE-only constructs like possessive quantifiers won't match.

Not currently — the hash tool produces fast cryptographic digests (MD5, SHA family) intended for checksums and integrity checks. For password hashing you should use bcrypt/argon2 in your backend, never client-side.

It handles JSON files up to tens of megabytes comfortably in a modern browser. For multi-gigabyte files you'll want a streaming parser like jq on the command line, but for everyday API responses the formatter is instant.

Yes. UUIDv4 values come from crypto.getRandomValues, giving 122 bits of randomness. The collision probability is astronomically low — safe to use as primary keys in databases and distributed systems.

Your files never leave your device

Every tool on Xevon Tools runs 100% in your browser. No uploads, no servers, no tracking. Free forever.

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