Developer Tools
Small, dependable utilities for everyday development work. Every tool runs client-side, so API responses, credentials and data samples never leave your machine.
11 free tools
JSON Formatter
Paste minified or messy JSON and get a cleanly indented, readable version. Invalid JSON produces an error with the line and position of the problem.
JSON Minifier
Strip every unnecessary space and line break from JSON to get the smallest valid representation — with the size saving shown.
JSON Validator
Check whether a JSON document is valid. Errors are reported with line and column, plus a plain-English explanation of the likely cause.
CSV to JSON
Turn CSV data — pasted or from a file — into a JSON array of objects, using the header row as keys. Quoted fields and embedded commas are handled correctly.
JSON to CSV
Convert a JSON array of objects into CSV that opens cleanly in Excel or Google Sheets, with correct quoting and a stable column order.
URL Encode/Decode
Percent-encode text for URLs, or decode %20-style strings back into readable text. Choose component encoding (strict) or full-URL encoding.
Base64 Text
Convert text to Base64 and back. Unlike naive implementations, this handles UTF-8 correctly, so emoji and non-Latin text round-trip safely.
UUID Generator
Generate version-4 UUIDs using your browser's cryptographic random source. Create one or a batch, with uppercase and hyphen-free formatting options.
Password Generator
Create strong random passwords with control over length, symbols, digits and ambiguous characters. Generated locally with cryptographic randomness — never transmitted.
QR Code Generator
Create a QR code from any text or URL and download it as PNG or scalable SVG. No watermark, no expiry — the code is generated in your browser.
Color Converter
Convert any color between HEX, RGB and HSL formats instantly. Type a value in any field or use the visual picker — the other formats update live, with one-click copy for your CSS.
About developer tools
This category covers the small, frequent tasks that come up constantly while building software: formatting and validating JSON, converting between CSV and JSON for reporting, encoding and decoding URLs and Base64 strings, and generating UUIDs, strong passwords and QR codes.
Because API responses, tokens and config data sometimes contain sensitive information, every tool here runs entirely in your browser using the same JavaScript and Web Crypto APIs your own code would use — nothing is sent to a server, logged, or stored anywhere.
Why use these tools
No uploads, ever
Files are read and processed by your own browser. Nothing is transmitted to a server.
Instant results
No upload queue and no round-trip, so most conversions finish before a server would have finished receiving the file.
Free, no account
No sign-up, no email, no watermarks and no trial limits. Close the tab and nothing is retained.
Works everywhere
Runs in any modern browser on Windows, macOS, Linux, Android and iOS. Nothing to install.
Frequently asked questions
Do I need to create an account?
Are my files uploaded anywhere?
Which browsers are supported?
Other categories
Image Tools
Convert, compress and edit images without installing software. All image tools on this page run entirely in your browser, so your photos are never uploaded to a server.
14 toolsPDF Tools
Combine, split and reorganize PDF files directly in your browser. Your documents stay on your device — nothing is uploaded.
14 toolsText Tools
Quick utilities for counting, cleaning and transforming text. Paste your text, get the result instantly — nothing you type leaves your browser.
8 tools