About lardr.dev

Every developer keeps a mental list of little conversions they need a few times a week — decode this Base64, format that JSON, work out what this cron expression actually does. The sites that offer them are usually slow, buried in advertising, and quietly upload whatever you paste to a server you know nothing about.

lardr.dev is the version of that without the annoyances.

Two promises

It runs in your browser. Tool input is processed on your own device and never transmitted. Open the network inspector and check — no request goes out. The only exceptions are lookups that are impossible without a server, such as DNS, and those say so on the page before you use them.

It's fast. Pages are static HTML with no framework runtime. A tool's JavaScript is a few kilobytes and loads only on the page that needs it. There is no loading spinner because there is nothing to wait for.

How it's built

Static pages generated with Astro, plain TypeScript for the tools, no UI framework, and no analytics that identify anyone. Each tool's logic is a pure function covered by unit tests — including the examples shown on its own page, so the documentation can't drift from the behaviour.

Hosted on Cloudflare Pages.

Will there be ads?

Probably, eventually — hosting and time aren't free. If that happens, ads will sit below the tool rather than in front of it, the layout won't jump around, and the privacy policy will be updated before a single ad is served. The promise that your input stays in your browser is not up for negotiation.

Requests and corrections

Missing a tool, or found one giving a wrong answer? Wrong answers are the ones that matter most — get in touch at [email protected].