I built 59 free browser-based dev tools in vanilla JS — here's what I learned
I've been quietly building Antigravity Tools — a collection of 59 free, browser-based developer utilities — and today I'm sharing everything I built and learned. Why vanilla JS? No React, no build step. The main constraint I set for myself: zero dependencies, zero server, zero telemetry . When you paste your JWT token into jwt.io, it goes to their server. When you use an online regex tester, your…
In the span of a few months, I developed a suite of 59 free, browser-based developer tools called Antigravity Tools. These tools operate without any dependencies, without any server, and without any data being sent to external servers. All operations occur within your browser using native APIs such as Web Crypto API, Canvas API, Web Audio API, and IndexedDB.
The 59 tools are divided into eight categories. Security and authentication tools include a JWT Inspector for decoding and checking JWTs, an RSA and ECC Key Generator for creating 2048-bit key pairs, and a PII Masker for removing sensitive information from text. AI and prompting tools consist of an AI Token Counter for estimating costs across various language models, a System Prompt Builder for creating agent instructions, an AI Text Humanizer to make AI output sound more natural, and a Prompt Cost Trimmer to reduce API costs by compressing prompts.
Development and code tools in the suite include a JSON Workbench for beautifying, validating, and converting data to various formats, a cURL Converter to translate cURL commands into browser-based fetch, request, or API calls, and a Regex Tester for real-time matching and display of capture groups. The Cron Builder provides a visual editor for creating and understanding cron expressions, while a Git Command Helper helps build visual representations of complex Git commands like undo, squash, and cherry-pick.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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