Antigravity Tools: 59 free browser-based dev utilities with zero dependencies or telemetry

A developer has released Antigravity Tools, a suite of 59 free utilities that run entirely in the browser, built with plain JavaScript and none of the tooling that usually surrounds a modern web app. In a post published on dev.to on 6 September 2026, author Yuvaraj Radhakrishnan describes the project and the strict constraints behind it: no third-party libraries, no backend, no analytics, no cookies.

Privacy as the starting point

The motivation, according to the dev.to post, is that many popular web utilities are not private. Paste a JWT into a token-inspection site and the token may travel to that site's servers; type test strings into an online regex tester and they can end up in logs. Antigravity Tools was built so every operation happens inside the browser, using native platform APIs instead of server round-trips.

The stated architecture avoids Node.js entirely: there is no backend, no npm packages and no bundler such as webpack, Vite or Parcel. There is also no Google Analytics and no cookies. The heavy lifting is done by APIs already shipped in modern browsers — the Web Crypto API, the Canvas API, the Web Audio API and IndexedDB.

What the collection contains

The tools are organised into eight categories, of which the post highlights three.

The security and authentication set includes a JWT inspector that decodes token headers and payloads and checks expiry locally; an RSA and ECC key generator that produces 2048-bit key pairs through SubtleCrypto; a hash and password generator using SHA-256 and SHA-512 via Web Crypto; a PII masker that strips emails, credit card numbers, social security numbers and IP addresses from text; and a universal encoder and decoder covering Base64, URL, hex, HTML entities and Unicode.

An AI-focused category reflects current developer workflows. A token counter estimates costs across GPT-4o, Claude 3.5, Gemini 2.0 and DeepSeek R1; a system prompt builder structures agent instructions with XML tags and tool definitions; a text humanizer reworks machine-sounding output; and a prompt cost trimmer claims to compress prompts by 30–50 per cent to cut API bills.

The general development category covers everyday tasks. A JSON workbench beautifies, validates and converts JSON into TypeScript, Python and Go types. A cURL converter turns cURL commands into JavaScript fetch, Python requests, Go and PHP equivalents. A regex tester offers live match highlighting with capture-group display, a cron builder provides a visual editor with plain-English explanations, and a git helper assembles undo, squash and cherry-pick commands interactively.

The full collection is available at antigravitytools.app.

A zero-build proof of concept

Beyond the individual utilities, the project works as a demonstration of how far native browser APIs have come. Cryptographic key generation, hashing, local persistence and format conversion — tasks that once justified a server or a library — are handled here by SubtleCrypto, Web Crypto, IndexedDB and friends, with no framework in sight.

Why it matters

Developers routinely paste sensitive material — live JWTs, API keys, customer data — into convenient web tools, and often have no way of knowing what happens to it on the other end. A collection that keeps every operation client-side removes that exposure by construction.

The zero-dependency approach also sidesteps the supply-chain risks that come with npm packages, and the absence of a build step keeps the project simple to audit and maintain. It is a useful data point in the ongoing argument that the web platform on its own is often enough.

One caveat: everything above comes from a single first-person announcement, so the capabilities and cost-saving figures have not been independently verified.