Data & Developers

Pretty-print, validate and fix JSON free online — turn a minified one-liner into readable, indented JSON and catch errors instantly.

Minify CSS, JavaScript and HTML free online to shrink file size and speed up your site — what minification does and when to use it.

Convert Unix timestamps to human dates and back free online — what epoch time is, why developers use it, and the year-2038 problem.

Check and understand an IP address free online — public vs private, IPv4 vs IPv6, and what your IP does (and doesn't) reveal about you.

Check if a card number is validly formatted with the Luhn algorithm free online — how the checksum works and what it does (and doesn't) prove.

Convert Excel (.xlsx, .xls) to CSV for free in your browser — no software, no signup, and your file is never uploaded. Step-by-step guide.

Convert CSV to a real Excel .xlsx workbook for free — columns split correctly, no software, nothing uploaded. Quick browser-based guide.

Convert Excel or CSV to a clean JSON array of objects for free — perfect for APIs, seeding databases and JavaScript. Runs in your browser.

Convert CSV to JSON and JSON to CSV free in your browser — with correct quoting and nested handling. Simple guide for developers and analysts.

Format and beautify minified CSS, HTML and XML into clean, readable code — free online, in your browser. When to minify vs beautify.

Convert JSON to YAML free online for Docker, Kubernetes, GitHub Actions and config files — what changes, when to use YAML, and a quick converter.

Generate TypeScript interfaces from a JSON sample for free — nested types included. Stop hand-typing API response types.