localbench

Client-side file tools. Your files never leave your device.

Every operation runs in your browser over WebAssembly. No upload. No account. No ads. Free and open-source.

Working codename. Real product name is a later branding decision.

Why

The big file-tool sites (Smallpdf, iLovePDF, Adobe online, cloudconvert) all upload your file to their servers, then paywall or ad-gate the basic operation. The upload is their business model. localbench does the work in your browser instead - so your file physically never leaves your machine.

That promise is only worth anything if you can verify it, so:

• Fully static, no backend. Nothing to upload to.
• Strict CSP (connect-src 'self') - WASM and app assets can load only from the same static origin, while external exfiltration is blocked.
• Works offline. Install it, pull your network cable, it still works. That is the proof.
• Open source. Read the code.

Status

S0 proves the Rust → WASM → worker → UI pipeline with a local PDF page counter. The later V1 anchor remains PDF ops (merge / split / page-ops / compress). See docs/V1-SPEC.md.

Concept + wedge analysis: mtclab/ideas #9.

Stack

Rust core compiled to WebAssembly (all file logic), driven by a thin vanilla-TypeScript shell. WASM runs in Web Workers; PWA for offline; hosted on Cloudflare Pages. Minimal dependencies by design (smaller = more auditable).

Built by MTC Lab.

Build and verify

Prerequisites: Rust with the wasm32-unknown-unknown target, wasm-pack, and Node.js 22.

wasm-pack build core-rs --target web --out-dir ../app/src/wasm
cd app && npm ci && npm run build
cd .. && node scripts/check-local.mjs

The ../app/src/wasm path is resolved by wasm-pack from the core-rs crate directory. make build runs this same pipeline. Cloudflare Pages should use app/dist as its output directory; deployment is intentionally handled through the owner's dashboard Git integration.

The CSP permits only same-origin connections because the origin serves static app assets and WASM—there is no server upload endpoint. wasm-unsafe-eval is the sole eval-class allowance and is required for WebAssembly instantiation.