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…
I have quietly constructed Antigravity Tools, a compilation of 59 complimentary, browser-based developer utilities, and I am now sharing my creations and insights. The primary reason for using vanilla JavaScript, without React or any build process, is to ensure zero dependencies, zero server interaction, and zero telemetry. Each tool operates entirely within the browser, utilizing native APIs such as Web Crypto API, Canvas API, Web Audio API, and IndexedDB.
The toolset is divided into eight categories:
Security & Auth Tools:
- JWT Inspector: Decode JWT header, payload, and verify expiration locally.
- RSA & ECC Key Generator: Generate 2048-bit key pairs using SubtleCrypto.
- Hash & Password Generator: Create SHA-256/SHA-512 hashes via Web Crypto.
- PII Masker: Remove emails, credit cards, SSNs, and IPs from text.
AI & Prompting Tools:
- AI Token Counter: Estimate costs for GPT-4o, Claude 3.5, Gemini 2.0, and DeepSeek R1.
- System Prompt Builder: Structure agent instructions with XML tags and tool definitions.
- AI Text Humanizer: Rewrite robotic AI output into natural language.
- Prompt Cost Trimmer: Compress prompts by 30-50% to minimize API costs.
Dev & Code Tools:
- JSON Workbench: Beautify, validate, and convert JSON to TypeScript, Python, Go types.
- cURL Converter: Convert cURL commands to JavaScript fetch, Python requests, Go, or PHP.
- Regex Tester: Real-time match highlighting with capture group display.
- Cron Builder: Visual editor for cron expressions with plain-English output.
Git Command Helper: Build undo, squash, and cherry-pick commands visually. Access them all at https://antigravitytools.app.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
