BracketAbout Bracketly
A small, growing collection of developer tools, built one at a time.
Why this exists
Most free online dev tools share the same annoyances: a wall of ads before you can even see the input box, a page that phones home with whatever you paste into it, or a UI that hasn't been touched since 2014. Bracketly started as a personal itch — wanting a JSON formatter and a JWT decoder that were fast, uncluttered, and didn't need to send anything to a server to do their job. It grew from there, one tool at a time, whenever a real task needed something that didn't already exist in a form worth using.
What "runs entirely in your browser" means
Bracketly has no backend, no database, and no accounts — every tool on the site is plain JavaScript running on your own device using standard browser and Web APIs (JSON.parse, the Web Crypto API, crypto.getRandomValues, and similar). Whatever you paste into a tool — a JWT, a JSON payload, a document you're checking a citation against — is processed locally and never transmitted anywhere. That's not a policy decision layered on top of the tools; it's the only way most of them work at all, since there's no server for the data to go to. Full details, including what Cloudflare Analytics and Google AdSense do collect, are in the privacy policy.
What's here, and what's coming
The current set spans everyday formatting and encoding tools (JSON, Base64, URL encoding, Unix timestamps, UUIDs), a few security-adjacent utilities (JWT decoding, hash generation, regex testing), a color converter, a cron expression explainer, and a newer batch of tools for people building against LLM APIs and AI agent tooling — a GPT token counter, a Citations API response viewer, a Gemini thought signature validator, an MCP tool schema validator, an embedding vector truncator/renormalizer, an AI SDK stream protocol debugger, an MCP 2026-07-28 migration checker, an Agent Plugins manifest validator, an MCP Apps UI resource validator, an Agent Client Protocol message validator, a SKILL.md frontmatter validator for the Agent Skills format, an MCP Tasks extension validator, an MCP Registry server.json validator, an OpenTelemetry GenAI semantic conventions span validator, an x402 protocol payment payload decoder with real EIP-712/EIP-3009 signature verification, and a Claude memory tool & context editing validator that checks paths against a real, patched path-traversal CVE. New tools get added when a genuine gap shows up, not on a schedule, and always as an original implementation rather than a copy of something that already exists elsewhere.
Who's behind it
Bracketly is an independent, self-funded side project — no company, no investors, no roadmap beyond "build the next tool that's actually worth building." It's supported by a single unobtrusive ad per page and optional reader donations, and the full source is open on GitHub if you want to see exactly how any tool works or suggest a new one.