Developers lose a surprising amount of time to small, repetitive tasks: decoding a cron schedule, sanity-checking a regular expression, or hand-writing TypeScript interfaces for an API response. This page collects fast, focused utilities that take those chores off your plate — each one does a single job well, runs instantly, and stays out of your way.

Some of the tools are enhanced with AI where it genuinely helps, such as explaining a gnarly regular expression in plain English. The rest are deterministic and run entirely in your browser, so they are private, reliable, and always available.

• Regex Tester & AI Explainer — Test a regular expression against sample text with live match highlighting and capture groups, then get an AI-powered, plain-English breakdown of exactly what the pattern does.
• Cron Expression Explainer — Paste a cron expression to see a human-readable description, a field-by-field breakdown, and the next upcoming run times — all computed instantly in your browser.
• JSON to TypeScript — Paste a JSON object or API response and instantly generate strongly-typed TypeScript interfaces, with nested types, arrays, and optional fields handled automatically.

Every utility here started as a task I kept doing by hand. Decoding a cron line before a deploy, checking a regular expression against a log sample, turning a webhook payload into TypeScript interfaces — none of these are hard, but each one costs a few minutes and breaks concentration, and the free tools available for them are often slow, buried in advertising, or gated behind an account.

So they were built the way I wanted to use them: one job per tool, no sign-up, no upload step, and an explanation underneath so the tool teaches you something rather than just handing back an answer. The guides on each page are as much a part of the tool as the input box — a cron preview is only useful if you also understand why day-of-month and day-of-week combine with OR rather than AND.

The cron explainer, the JSON to TypeScript converter, the code playground, and the calculators run entirely in your browser. Nothing you paste into them is uploaded, logged, or stored anywhere — the computation happens on your own machine in JavaScript, which is why they work quickly and why it is safe to use them with private payloads and real numbers.

The one exception is the AI regex explanation. When you explicitly click to explain a pattern, the pattern and its flags are sent to a model provider to generate the walkthrough. Your test text is never sent. Nothing is sent until you ask for it, and the live matching and highlighting work without it. Full detail is in the privacy policy.

These tools are built carefully and tested, but they are aids to understanding rather than authorities. A cron preview uses standard five-field Unix semantics and your browser’s local timezone — your scheduler may use UTC, support extended syntax, or handle daylight saving differently. Generated TypeScript describes the sample you pasted, not every response an API can return. An AI explanation of a regular expression can be incomplete. In each case, verify against the real system before depending on the result; the disclaimer sets out the terms these tools are offered under.

The list grows based on what people actually ask for. If there is a task you keep doing by hand and it could plausibly run in a browser, describe it on the contact page — several of the tools here exist because someone did exactly that.