UUID / GUID generator
v4 (random), v7 (time-ordered), v1/v3/v5, nil. Bulk export, language guides.
Developer tools
Fast, private developer tools.
Eleven tools, each on its own subdomain, each under 30 KB. No signup, no upload, no laggy SPA. Open one, get the answer, close the tab.
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UUID / GUID generator
v4 (random), v7 (time-ordered), v1/v3/v5, nil. Bulk export, language guides.
Hash calculator
MD5, SHA-1, SHA-256, SHA-384, SHA-512. Text or file. Compare two hashes.
JWT decoder & verifier
Decode, verify HMAC (HS256/384/512), sign for testing fixtures. Web Crypto API.
JSON formatter
Format, minify, validate, convert to YAML. Browser-only, instant.
Generate
Create new IDs, secrets, codes.
Encode / decode
Move data between formats — base64, JWT, hash digests.
Format & parse
Make data readable — JSON, Markdown, cron expressions.
Test & compare
Validate or diff existing data — regex, text diff.
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Guides
Long-form posts on the practical problems each tool exists to solve.
- Is this browser tool really client-side? 6 min Three things to check in DevTools before pasting anything sensitive into any web tool.
- JWT decoded ≠ JWT verified 7 min Why pasting a JWT into a decoder doesn't tell you if it's valid — and what verification actually checks.
- JSON vs YAML vs JSONC vs NDJSON — when to pick which 8 min Four wire formats with overlapping use cases. The trade-offs each one makes — and the surprises.
- UUID v7 vs v4 — picking the right one in 2026 6 min v7 is now standard. When the time-ordered variant matters, when v4 is still right.
- Base64 is encoding, not encryption 5 min Five places engineers still confuse the two — and what each costs in production.
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