Tools
The toolbox
Small, sharp developer tools — built from scratch in vanilla TypeScript, free, no sign-up, and everything runs right here in your browser. Nothing you type is uploaded.
Regex Checker
Developer tool
Test regular expressions with live match highlighting, capture groups, named groups and a replace preview. JavaScript flavour, with a full quick-reference — everything runs in your browser.
Open Regex Checker →Diff Checker
Developer tool
Compare two texts or files and see every difference highlighted — down to the changed character inside a line, with moved lines recognised as moves, side-by-side and unified views, and an exportable patch. Nothing you paste ever leaves your browser.
Open Diff Checker →JSON Formatter
Developer tool
Format, validate and minify JSON with exact line-and-column error messages, sorted keys, and your choice of indentation. Everything runs in your browser — nothing is uploaded.
Open JSON Formatter →Base64 & URL Encoder
Developer tool
Encode and decode Base64 — standard or URL-safe — and percent-encoded URLs, fully UTF-8 safe where btoa-based tools choke. Instant round-tripping, exact error positions, and a hex preview when the payload turns out to be binary. Nothing you paste ever leaves your browser.
Open Base64 & URL Encoder →QR Code Generator
Utility
Turn text, a link or Wi-Fi credentials into a QR code — crisp SVG and PNG downloads, custom colours with scannability warnings, and your choice of error-correction level. No tracking redirects and no expiry: the code is built in your browser and encodes your actual content.
Open QR Code Generator →Color Palette Generator
Design tool
Build 5-color palettes from real color theory — lock what you like, regenerate the rest, export as CSS, Tailwind, SCSS or JSON. Or describe a mood and a small AI on this site's own server paints it.
Open Color Palette Generator →JSON to Code Converter
Developer tool
Paste JSON, get ready-to-use model classes in Dart, TypeScript, Python, Go, Kotlin or Swift — serialization included. Nullability, dates and int-vs-double inferred honestly, with warnings where your sample is thin.
Open JSON to Code Converter →Mock Data Generator
Developer tool
Build a schema — or describe it in plain English and let AI build it — then generate up to 1,000 rows of realistic fake data: names, emails, prices, dates. Seeded and reproducible, exported as JSON, CSV or SQL.
Open Mock Data Generator →Cron Parser
Developer tool
Paste a cron expression and see it in plain English with the next 10 run times in your timezone — or describe the schedule in words and let AI write the cron, verified against real dates before you trust it.
Open Cron Parser →Grounded
AI · RAG
Paste your own notes, an article or a transcript, then chat with them — grounded answers with clickable citations. It's retrieval-augmented generation you can watch work: the embeddings run on your device, and only the question plus the matched passages ever reach the server.
Open Grounded →What are these?
Utilities I wanted myself, built properly: each tool is written from scratch in this site's codebase with a pure, unit-tested core and no frameworks or third-party services. They work offline once loaded, store settings on your device only, and never upload what you type — the exceptions are Grounded, which is an AI tool by nature, and the palette, regex, mock-data and cron tools' opt-in AI assists; all of them send only your prompt to this site's own local model and nowhere else. No accounts, no tracking beyond the site's ads. The newest tools start life in beta — heavily tested, but if anything ever looks off, bug reports are very welcome. More tools are on the way; if there's one you'd like to see,tell me.