Developer Tools

33 Developer Tools That Every Programmer Uses Daily

Every developer has a mental list of tools they reach for constantly — a JSON formatter to make a wall of raw API data readable, a regex tester to check a pattern before pasting it into production code, a Base64 encoder when an API demands it, a diff checker when something changed and you need to know exactly what. Our collection puts 33 essential developer utilities in one place, each one fast, focused, and completely free.

JSON Formatter and Validator — Your Most-Used Dev Tool

If you work with APIs, you work with JSON. And raw JSON — especially from a log file or an API response dumped into a terminal — is practically unreadable. Our JSON Formatter takes that compact mess and pretty-prints it with proper indentation, colour-coded keys, and collapsible tree structure. It also validates the JSON as you paste — if there's a syntax error, it tells you exactly where. Paste it in, fix the issue, copy back out. The whole thing takes 10 seconds. It also works in reverse: paste formatted JSON and minify it to a single line for production use or embedding in config files.

Regex Tester — Write Patterns With Confidence

Regular expressions are powerful but notoriously difficult to write correctly on the first try. Our Regex Tester provides a live, real-time environment where matches highlight instantly as you type. You can test against multiple strings at once, toggle flags like global (g), case-insensitive (i), and multiline (m), and see exactly which parts of your pattern match. This is the difference between testing in production and knowing your pattern works before you ship. Developers debugging email validation patterns, URL parsers, or log file processors use this daily.

JWT Decoder — Inspect Tokens Instantly

JSON Web Tokens appear everywhere in modern authentication — OAuth flows, REST APIs, single-page application sessions. When something breaks in your auth system, the first step is checking what's actually inside the token. Our JWT Decoder splits any JWT into its three base64-encoded parts — header, payload, and signature — and presents them as readable, formatted JSON. You can instantly see the expiry time (the exp claim), the issuer, the user ID, any roles, and whatever else your application embeds. Important note: this tool decodes only — it does not verify the signature against a secret, so always validate signatures server-side.

Base64 Encoder and Decoder

Base64 shows up in more places than most developers expect — embedding images in CSS as data URIs, encoding credentials in HTTP Basic Auth headers, storing binary data in JSON, and passing parameters through URL-unfriendly channels. Our Base64 Encode/Decode tool handles plain text in either direction instantly. Paste your string, click Encode or Decode, copy the result. No page reload, no latency, no limits on input length.

Code Formatters for CSS, JavaScript, SQL, XML and YAML

Unformatted code is a liability — harder to read, harder to review, and easier to introduce bugs into. Our formatting tools clean it all up:

• CSS Beautifier — formats minified or poorly indented CSS with consistent spacing and structure
• JS Formatter — re-indents JavaScript for readability
• SQL Formatter — breaks long query strings into readable multi-line format with proper keyword casing
• XML Formatter — pretty-prints and validates XML structures
• YAML Formatter — formats and validates YAML configuration files

Each of these is a one-step operation. Paste, format, copy. No sign-in, no ads, no rate limits.

Diff Checker — See Exactly What Changed

The Diff Checker compares two blocks of text side by side and highlights every addition, deletion, and change. Paste the old version in the left panel and the new version in the right, and every difference lights up immediately. Useful for comparing config files before and after a deployment, reviewing what changed in a copied script, spotting edits in a document, or debugging why two supposedly identical strings are behaving differently.

More Utilities Every Developer Needs

The toolkit doesn't stop there. The Hash Generator produces MD5, SHA-1, SHA-256, and SHA-512 hashes from any input — useful for checksums, password verification tests, and data integrity checks. The URL Encoder/Decoder converts strings to and from percent-encoding for safe use in query strings. The UUID Generator produces RFC 4122 compliant unique identifiers on demand — great for test data, database seeds, or any situation where you need unique IDs. The HTML Beautifier and HTML Encoder/Decoder round out the toolkit for front-end developers working with markup.

API Tester — Test Endpoints Without Postman

The API Tester lets you send GET, POST, PUT, PATCH, and DELETE requests to any endpoint, add custom headers and a request body, and view the formatted response — all from your browser. It's a quick option when you need to verify an endpoint is working and don't want to open Postman or write a curl command.