rtro.dev/tools
Developer tools for dates, IDs and config
Small, focused tools for the formats you look up every week. Each one has its own page, keeps its input in the URL so a link reproduces the result, and explains the format underneath.
Runs entirely in your browser. Nothing you paste is sent anywhere./tools/unix-timestampUnix timestamp converterSeconds, milliseconds, microseconds or an ISO date, detected automatically.
1790853909000→2026-10-01T11:25:09.000Z
/tools/time-comparisonTime zone comparisonYour zones as rows, hours as columns, so a column is one instant. Pick a meeting slot.
Berlin · London · New York · Tokyo→16:00 · 15:00 · 10:00 · 23:00
/tools/uuidUUID / ULID generator and decoderGenerate v4, v7 or ULID in bulk. Decode any ID to its version and timestamp.
01a0f736-0a08-7c4e-9f13-…→UUID v7 · 2026-10-01T11:25:09.000Z
/tools/jsonJSON / YAML / TOML toolFormat and validate, convert between formats, and diff two files by structure.
{"plan":"free","seats":3,}→Unexpected token } at line 1, column 25
No server
Every tool is static JavaScript. Pasting a JWT, a config file or a customer ID never makes a network request.
Shareable links
Inputs live in the URL, so you can drop a link in a PR comment and the reader sees the same result.
Keyboard first
⌘K switches tools. ⌘↵ runs. Every output has a copy button.