Developer tools that run entirely in your browser.
Format, validate, decode and convert developer data instantly. No accounts, no uploads, no backend processing.
Instant
No round trips or waiting for an API.
Private
Tokens and payloads stay on this device.
Installable
Use ElDevo as a lightweight PWA.
Developer toolkit
Find the right tool quickly
ElDevo is a privacy-first hub for small developer tasks. Parsers, encoders, formatters and converters execute in the browser so sensitive tokens, source snippets and data files do not need to leave your machine.
Most developer utility sites route your input through a backend before returning a result. ElDevo takes a different approach: every tool on this site — from the JSON formatter and JWT decoder to the Base64, regex and SQL utilities — runs as JavaScript in your own browser tab. There is no upload step, no processing queue and no server-side log of what you pasted in. That also means the tools keep working once the page has loaded, even if your connection drops.
Frequently Asked Questions
Is ElDevo really free?
Yes. Every tool, converter and cheatsheet on ElDevo is free to use, with no account, subscription or usage cap.
Where is my data processed?
Directly in your browser. Tools use client-side JavaScript, so pasted text, files and tokens are not sent to an ElDevo server for processing.
Does ElDevo work offline?
Yes for most tools. ElDevo registers a service worker so the app shell and previously visited tools continue to work without an internet connection.
How many tools does ElDevo have?
ElDevo covers JSON, encoding, security, regex, HTML/CSS/JavaScript, SEO, calculators, images and more — organized under Tools, Converters and Cheatsheets so you can find what you need quickly.