Developer & Utility Tools
Free utilities for working with JSON, UUIDs, text diffs, QR codes, and passwords — all running in your browser without sign-up.
Password strength checker
Estimate password strength without sending it anywhere.
FeaturedUUID generator
Generate UUIDs — v1 through v8 — and export in bulk.
QR code generator
Turn any text or URL into a downloadable QR code.
FeaturedJSON formatter
Format, validate, query, diff, and convert JSON — up to 50MB.
Text diff checker
Compare two text blocks and see what changed.
About developer & utility tools
Developer tools are the small utilities you reach for several times a day: format a messy JSON payload, generate a handful of UUIDs, compare two config files to see what changed, turn a URL into a QR code for a slide, or check whether a password is strong enough to ship. The kind of thing that should take ten seconds.
Everything here runs in your browser. The JSON formatter parses and validates up to 50 MB without uploading a single byte. The password strength checker never sends your password anywhere — strength is estimated entirely client-side. The UUID generator supports every RFC 4122 version from v1 to v8, with bulk generation and CSV export.
These tools aren't meant to replace your editor or command line. They're for the moments where opening a new IDE window or writing a Python one-liner is overkill.
Related guides
Frequently asked questions
Can I use these tools for sensitive input?
Yes. The password strength checker, JSON formatter, UUID generator, QR code generator, and text diff all run locally. Input never leaves your browser, and we don't see what you paste.
How large a JSON file can the formatter handle?
Up to around 50 MB, depending on your device's available memory. The formatter streams parsing where possible to avoid long freezes. For multi-gigabyte files, a command-line tool like jq will still serve you better.
Is the password strength checker accurate?
It's a reasonable local estimate based on length, character classes, and common-password lists. It's not a substitute for a password manager's own strength advice, and it doesn't know whether your password has appeared in a breach. See the tool page for the full method.
Which UUID version should I use?
v4 (random) is the default for most needs — unique, non-sequential, no coordination required. v7 (time-ordered) is a good choice for database primary keys where you want sortable IDs. The UUID generator covers v1, v3, v4, v5, v6, v7, and v8.