Developer tools online

If you write or read code for a living, you spend a surprising amount of time on small chores: pretty-printing some JSON, diffing two API responses, testing a regex, explaining a cron expression, converting snake_case to camelCase, writing Markdown, calculating a fluid CSS clamp() value. None of these tasks deserve a desktop app, an account, or a paid SaaS. They deserve a fast browser tab.

Every developer tool here is built around the same idea: open the page, paste or type, get the result, close the tab. There is no signup, no upload, no log of what you typed. Whatever you put in stays on your machine — useful when the value you are formatting is a production token, a database row, a customer record you are debugging, or an unreleased design system spec.

The tools below cover the everyday parts of a developer workflow: structured-data formatting (JSON, XML, YAML), structural diffing, regex testing, cron scheduling, text case conversion, Markdown authoring, and modern CSS utilities. Each one is a single page with a clear input, a clear output, and the long-form documentation a search engine actually wants to rank.