Free Developer Utilities
No sign-up, no install. Format JSON, decode JWTs, convert timestamps, test regex, create PDF invoices, generate signatures, and more — privacy-first tools that run entirely in your browser.
Privacy-first
Your data stays on your device. No accounts, no tracking on the tools you use.
Smart utilities
30+ focused tools for everyday dev work — fast, keyboard-friendly, and free.
JSON
JSON Formatter & TypeScript Generator
Format and validate JSON. Generate TypeScript interfaces from JSON. Copy or download output.
JSON to CSV Converter
Convert JSON array to CSV. Flatten objects and download or copy CSV.
JSON to Code Generator
Convert JSON to TypeScript, Python, Java, Go, Rust, or C#. Select output language and generate types or classes.
JSON Compare
Compare two JSON documents structurally. Object key order is ignored; see aligned paths, added, removed, and changed values.
Data & Format
Format Converter
Convert between CSV, JSON, XML, and YAML. Select source and target formats.
SQL Formatter
Format and beautify SQL queries. Indent and uppercase keywords.
Diff Checker
Compare two texts or code blocks. Side-by-side and unified views.
Markdown Previewer
Preview Markdown as HTML. Export rendered output.
HTML to Markdown Converter
Convert HTML to Markdown. Paste HTML and get clean Markdown output.
Color Converter
Convert between HEX, RGB, and HSL color formats.
Encoding
Base64 Encoder / Decoder
Encode and decode Base64 strings. Works with text and binary data.
URL Encoder / Decoder
Encode and decode URL parameters. Percent encoding support.
Cookie Header Viewer & Compare
Parse Cookie header strings into name/value pairs. Compare two cookie headers side by side with added, removed, and changed values.
Query Params Compare
Compare query strings or full URLs. See which parameters differ, including repeated keys.
HTML Entity Encoder
Encode and decode HTML entities (&, <, >, ", ').
Security & Auth
Bcrypt Generator
Hash passwords with bcrypt. Compare hashes to verify.
Password Generator
Generate secure random passwords. Customize length and character types.
SHA256 Generator
Generate SHA256 hashes from text. Fast, client-side hashing.
JWT Decoder
Decode and inspect JWT tokens. View header, payload, and expiration.
JWT Generator
Generate JWT tokens with custom header and payload. Sign with HMAC-SHA256. Pair with JWT Decoder.
Generators
UUID Generator
Generate UUID v4. Bulk generation and copy to clipboard.
Random Data Generator
Generate bulk random strings, numbers, UUIDs, hex, and JSON primitives. For structured users, products, and orders, use the Test Data Generator.
Test User & Test Data Generator
Generate 1–10,000 synthetic users, products, or orders. Copy or download JSON, CSV, SQL, and YAML. Pick fields and localize for QA.
Multilingual Placeholder Text Generator
Generate realistic placeholder content in 16 languages for UI, website, localization, and app testing. Includes Arabic and Hebrew RTL plus mixed-language mode.
Business Tools
PDF Invoice Generator
Free online invoice maker. Create professional PDF invoices in your browser—seller, buyer, line items, tax, and notes. No signup, no upload.
Signature Generator
Free online signature maker. Draw or type a signature and download a PNG—transparent background, no signup, runs in your browser.