About DevFormatLab
A focused toolkit for data formatting and conversion.
DevFormatLab is a developer-first toolkit centered on one job: making data easy to read, write and move between formats. JSON, YAML, CSV, XML and regular expressions — all handled instantly inside your browser.
Every tool is designed around three principles: privacy (browser-only, no upload), speed (instant, no network round-trip) and clarity (minimal, distraction-free UI).
We pay special attention to real-world edge cases — UTF-8 ⇄ Shift-JIS conversion, mojibake detection, multi-row CSV cleanup and locale-aware date / timestamp handling — because the painful parts are exactly what makes a toolkit worth using.
The site is built with Next.js 14, TypeScript and Tailwind CSS, and statically generated for maximum performance.
Who writes for DevFormatLab
DevFormatLab is maintained by a small team of working software engineers based in Hong Kong and Singapore. We build tools we use ourselves every day — debuggers, JSON viewers, timestamp converters — and we publish what we learn so other developers can avoid the same mistakes.
Every tool on this site is hand-written, tested against the relevant IETF / ECMA / W3C specification, and reviewed by at least one engineer before each release. We never use AI to generate the prose you read here — the words are ours, and so are the mistakes.
How we review our tools
Each tool page documents the specification it implements (RFC 8259 for JSON, RFC 4180 for CSV, RFC 6902 for JSON Patch, etc.), the scope of inputs it accepts, and the limits it deliberately enforces. We publish those limits instead of hiding them, so you know exactly what the tool can and cannot do.
Editorial review runs on a quarterly cadence. When a page is rewritten we update its 'Last reviewed' stamp; older stamps remain visible so you can tell whether what you are reading is fresh.
If you spot an error we have not yet caught, please email editorial@devformatlab.com with a short repro. We respond within two business days and credit the reporter in the changelog when a fix ships.
Reproduction steps are most helpful; full payloads are not required, and anything you send us stays on our review queue. editorial@devformatlab.com