24 Free Developer & Code Tools

A Complete Developer Toolkit in Your Browser

Format, validate, minify and convert JSON, SQL, HTML, CSS, JS, XML, YAML and CSV. Decode JWT, generate UUIDs and hashes, test regex and APIs, parse URLs and cron expressions — all client-side, all free.

Explore the Developer Tools

Format

JSON Formatter

Format, minify, and validate JSON with syntax highlighting.

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Format

SQL Formatter

Format SQL queries with proper indentation and syntax highlighting.

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Format

HTML Formatter

Format HTML with proper indentation and tag alignment.

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Format

CSS Formatter

Format and minify CSS with proper indentation.

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Format

JS Formatter

Format and minify JavaScript code with proper indentation.

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Live Test

Regex Tester

Test regular expressions with input text, show matches, groups, and replacements.

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JWT

JWT Decoder

Decode JSON Web Tokens to see header, payload, and signature. Validate expiration.

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UUID

UUID Generator

Generate UUID v4, v1, nanoid. Batch generation, copy all.

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SHA

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-512 hashes from text input.

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Cron

Cron Parser

Parse cron expressions and show next 10 execution times in human-readable format.

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API

API Tester

Test REST APIs in your browser — send GET/POST/PUT/DELETE with custom headers and body.

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Validate

JSON Validator

Validate JSON syntax with clear, line-numbered error messages.

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Diff

JSON Diff

Compare two JSON documents side by side with color-coded, deep-nested diff.

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Format

XML Formatter

Format, beautify, and minify XML code with validation.

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Minify

CSS Minifier

Minify and compress CSS to reduce file size and speed up page loads.

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Minify

HTML Minifier

Minify and compress HTML to reduce file size and improve load speed.

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Minify

JS Minifier

Minify and compress JavaScript for smaller production bundles.

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Encode

HTML Entity Encoder / Decoder

Encode and decode HTML entities for special characters.

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Convert

Number Base Converter

Convert numbers between Binary, Octal, Decimal, and Hexadecimal bases.

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Time

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and back.

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URL

URL Encoder / Decoder

Encode, decode, and build URLs with live query-parameter editing and batch support.

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Parse

URL Parser

Parse any URL into its components — protocol, host, path, and query params.

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Code

cURL to Code Converter

Convert cURL commands into JavaScript (Fetch, Axios), Python (Requests, HTTPX), Go, PHP, and Rust code instantly.

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React

HTML to JSX Converter

Convert HTML code into clean React JSX components with camelCase properties, class to className, and style objects.

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A Browser-Based REPL for Everyday Dev Work

These tools replace the small one-off scripts developers reach for daily — prettify a JSON response, decode a JWT to see when it expires, generate a UUID for test fixtures, hash a string to verify a checksum, or sanity-check a regex against sample input. Doing it in the browser skips the install, the script file, and the network round-trip.

Coverage spans code formatters (JSON, SQL, HTML, CSS, JS, XML), minifiers (HTML, CSS, JS), encoders & hashes (Base64, HTML entities, MD5–SHA-512), IDs & timestamps (UUID, cron parser, Unix timestamp converter), API & URL utilities (API tester, URL parser, URL encoder, number-base converter), and data converters (JSON↔CSV, JSON↔YAML, XML↔JSON, JSON diff). For CSS visual generators — box-shadow, border-radius, gradients, and the WCAG contrast checker — see the Color & Design hub.

Putting the toolkit in a tab means there is no npm install, no node_modules bloat, and no CLI to forget the syntax of. Open the page, paste your input, get the output — your payloads never leave the development machine, which matters when you are debugging against production-shaped JWTs or scrubbing real API responses.

Key Advantages of ToolWise Developer Tools

Zero Footprint: No installs, no accounts, no API keys — paste and go, even from a corporate network that blocks package installs.
Absolute Privacy: Payloads, tokens, and credentials stay on your device. JWTs and request bodies are never forwarded over the internet.
Format Fluency: Round-trip between JSON, CSV, YAML, XML, HTML, Markdown, and back without losing structure or order.
Instant Validation: JSON and XML linters point at the exact line and column of the syntax error — no guessing where the brace went wrong.

Frequently Asked Questions

Will my JSON data, JWT tokens, or API credentials be logged?

Never. Security and developer privacy are our core principles. JSON formatting, JWT decoding, Base64 operations, regex testing, and hash generators run entirely within your local client sandbox.

Can the JSON Formatter handle malformed or large JSON datasets?

Yes. The JSON Formatter provides precise line-and-column error highlighting for syntax errors and easily handles multi-megabyte payloads for pretty-printing or minification.

Does the Regex Tester support standard JavaScript regular expressions?

Yes. Our Regex Tester supports standard ECMA regex syntax, live match highlighting, capture groups, and common regex flags (g, i, m, s, u).

Are hash generators cryptographically accurate?

Yes. All MD5, SHA-1, SHA-256, and SHA-512 hashes are generated using standard Web Crypto API implementations, ensuring identical outputs to Unix CLI utilities.

100% Private

Every formatter, validator and decoder runs in your browser. No payloads are uploaded to a server.

Always Free

No API keys, no rate limits, no signups — the full developer toolkit is free forever.

Instant & Offline

Client-side processing means instant results — even with no network connection.