HTTP load testing,
on your desktop.

LoadCell is a native app for hammering HTTP endpoints and watching what happens. Constant, ramp, or hand-drawn load curves — with live RPS, latency percentiles, and error breakdowns.

Get it View on GitHub

Or pick a different platform · build from source

LoadCell results dashboard: saved requests sidebar, request URL with success and latency metrics, and a stacked bar chart of 2xx versus failed requests over a 100-second run.
What it does

Built for the long press of "go."

Designed around the actual rhythm of load testing: pick a target, shape the load, watch it unfold, and read the result without deciphering a wall of JSON.

Live metrics

p50, p95, p99 latency, RPS, and error breakdowns by 4xx / 429 / 5xx / network — streaming as the test runs, not after.

Constant, ramp, or curve

Hold steady load, linearly ramp users, or draw a custom curve with linear / exponential / step segments and optional noise.

Saved requests

Persist method, URL, headers, and body as named templates so you can rerun the same scenario across builds and environments.

Native, not a CLI

Wails-powered desktop app: real windows, real keyboard shortcuts, no terminal panes — with a Go engine doing the actual work.

Local only

No accounts, no telemetry, no cloud round-trips. Your request templates live on your disk, and your traffic goes straight to the target.

Open source

Go engine, Svelte UI. Read the code, file an issue, send a PR, or just fork it and make it yours.

Get it

Grab a build.

Prebuilt binaries are cut on demand from the GitHub Actions release workflow. Pick your platform — or build from source if you'd rather.

macOS

Universal binary · Apple Silicon + Intel

Download .tar.gz All releases →

Windows

Standalone .exe · x64

Download .zip All releases →

Linux

Standalone binary · amd64

Download .tar.gz All releases →
macOS Gatekeeper will flag the binary on first launch

The binary isn't notarized (yet), so the first launch shows "cannot be opened because the developer cannot be verified." Two quick ways past it:

  1. Right-click loadcell.app → Open, then confirm in the dialog.
  2. Or in Terminal: xattr -dr com.apple.quarantine /Applications/loadcell.app
Build from source

Three commands.

LoadCell uses Wails for the desktop shell. If you have Go and Node installed, you're already most of the way there.

  1. 1
    Install prerequisites
    Go 1.21+, Node 18+, and the wails CLI.
  2. 2
    Clone the repo
    Grab the source from GitHub.
  3. 3
    Build or run
    wails dev for hot reload, or wails build for a redistributable. 
# 1. Install the Wails CLI (one-time)
go install github.com/wailsapp/wails/v2/cmd/wails@latest

# 2. Clone & enter the repo
git clone https://github.com/RobiMez/loadcell.git
cd loadcell

# 3. Run in dev mode...
wails dev

# ...or build a redistributable
wails build