Handy developer utilities

Mock data, CSV, JSON diff, ULID, regex, IP/CIDR and more - 12 tools right in your browser. No signup, no upload.

Fully private

Everything runs inside your browser. Nothing you paste is ever uploaded.

Copy-ready output

JSON, CSV, Markdown, SQL and code you can paste straight in.

Works offline

No external libraries - it keeps working without an internet connection.