UUID Generator
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Generate UUIDs for apps, tests, and databases.
- On your device
- No signup
Developer topic guide
UUID tools
Generate and decode UUIDs with free developer tools on your device.
1 free tool in this guide — pick one below to get started.
Tools in this guide(1)
Open a tool to calculate, convert, or edit — no signup required.
Overview
UUID tools create version 4 identifiers for database keys and trace opaque IDs in logs. Generator produces random UUIDs; Lookup explains version and variant bits when decoding.
UUIDs are not guaranteed unique across systems unless you use proper generation libraries in production services. Use these tools for ad hoc testing and debugging.
When storing UUIDs in URLs, prefer lowercase canonical form to avoid duplicate cache entries.
How to choose
- New random ID → UUID Generator.
- Inspect existing UUID → UUID Lookup.
Frequently asked questions
Which UUID version is generated?
See UUID Generator — typically version 4 random UUIDs.
Can UUIDs collide?
Collision risk is negligible for v4 at normal scale, but databases still need unique constraints.
Is generation cryptographically secure?
Browser crypto APIs are used where supported; see tool limitations for details.
Step-by-step workflows (10)
Multi-step guides that chain tools from this topic—follow numbered steps instead of guessing tool order.
- Debug a JWT or API tokenDecode a bearer token, pretty-print JSON claims, and inspect Base64 segments.3 steps
- Provision staging credentialsGenerate passwords, UUIDs, and hashes for dev, QA, and fixture data.3 steps
- Debug a failing APIReproduce the request, format the JSON response, inspect JWTs, and compare payloads.5 steps
- Validate JSON before deployValidate syntax, pretty-print, generate a schema draft, and diff against the previous payload.4 steps
- Ship a CSS UI tweakPrototype in the playground, generate layout and effect CSS, then check contrast.6 steps
- Turn a spreadsheet into an API payloadPreview CSV, convert to JSON, format, and validate before posting to an API.4 steps
- Verify a download with checksumsHash the file you downloaded, compare digests, and encode strings when docs ship Base64.3 steps
- Pre-launch domain and TLS checkConfirm DNS, WHOIS, SSL certificates, and security headers before go-live.4 steps
- Write and test a regexTest patterns live, consult cheat-sheet examples, and diff sample outputs.3 steps
- Backend ops cheat sheetBuild cron schedules, explain expressions, convert timestamps, and tidy env files.4 steps