About devnestio

devnestio is a growing collection of 150+ free, browser-based tools built for developers, designers, and anyone who works with code day to day. Every tool — from encoders and formatters to calculators, generators, and quick-reference sheets — runs entirely in your browser tab. There's nothing to install, no account to create, and no data uploaded to a server just to get an answer.

Why devnestio exists

Developers constantly need small, single-purpose utilities: decode a JWT, format some JSON, calculate a subnet, check a color's contrast ratio. Searching for a trustworthy tool for each of these tasks, one at a time, wastes time. devnestio brings dozens of these everyday utilities together in one place, built with the same care so you can trust the output and move on with your work.

How it works

• Every tool runs client-side in your browser using standard web APIs — there's no backend processing your input.
• No sign-up, login, or account is required for any tool.
• Tools are free to use for personal and commercial projects.
• New tools are added regularly based on common developer needs.

Who built this

devnestio is an independently built and maintained project. It's supported by ads and the occasional "buy me a coffee" tip so the tools can stay free for everyone.

Questions or feedback

Have an idea for a new tool, or found a bug? Feedback helps shape what gets built next. Check out the full tool directory to see everything currently available, or read our privacy policy for details on how the site handles data.