At the start of this year I began building Flux, an open source alternative to Postman. The goal was simple: an API client that feels light, runs natively and keeps your work on your own machine.

I launched it in July, and as of today it has a little under 500 downloads, which is more than I expected when I started.

What it is

Flux is a native desktop API client built with Tauri 2, Rust and React. It uses under 30 MB of RAM and the installer is around 9 MB.

It's local-first: your collections and requests live on your machine, and cloud sync is optional, not a requirement.

Besides regular HTTP requests, it has a few things built in that I'd normally need separate tools for:

gRPC support

Load testing , so you can hit an endpoint hard without installing anything else

Mock servers , for when the backend isn't ready yet

AI helpers : generating test suites, diagnosing errors, autocomplete, and editing request bodies in plain language

Why Tauri instead of Electron

Electron ships a full copy of Chromium…