configdiff-web
A browser playground for configdiff —
the Rust semantic config-diff library compiled to WebAssembly. Paste two config
files (TOML, YAML, JSON, INI, or .env), and see the semantic diff instantly,
entirely client-side. No server, no upload — nothing leaves your machine.
▶ Live demo: https://nico-perales.github.io/configdiff-web/
It compares by value and structure, not text: reordered keys don’t show up, and a
number that silently became a string is flagged as a type change — across
formats (e.g. an old config.toml vs the config.yaml that replaced it).
How it works
configdiff (Rust library)
│ wasm-bindgen
▼
configdiff_web.wasm ──▶ loaded by index.html (plain HTML/CSS/JS) ──▶ runs in the browser
The Rust crate in src/lib.rs wraps configdiff::diff_str behind a single
#[wasm_bindgen] function that returns the diff as JSON; the page renders it. The
whole thing is static files served from GitHub Pages — the diff runs in your
browser via WebAssembly, so it works offline once loaded.
Build locally
Requires a Rust toolchain and wasm-pack.
rustup target add wasm32-unknown-unknown
wasm-pack build --target web --out-dir web/pkg --release
Then serve the web/ directory over HTTP (module scripts and .wasm need a real
server, not file://):
npx serve web
Deployment
Pushing to main triggers a GitHub Actions workflow (pages.yml)
that builds the WebAssembly and deploys web/ to GitHub Pages. Enable it once under
Settings → Pages → Source: GitHub Actions.
License
Licensed under either of Apache-2.0 or MIT at your option.