A privacy-first, 100% local full-page screenshot and annotation extension for Chrome, Edge and Firefox.
Capture a full page, the visible viewport, or a hand-picked region — then crop, arrow, rectangle, blur, or watermark it, and export as PNG or PDF. Every pixel operation happens on your machine, in a Rust/WebAssembly core — nothing is uploaded anywhere, no account is needed, and the capture pipeline never has standing access to any page you haven't explicitly asked it to capture.
Most "free" screenshot tools fund themselves one of two ways: your images pass through their servers (openly, for sync/sharing — or, historically, less openly), or the free tier is a funnel toward a subscription. Neither is inherently malicious, but it means your screenshots — which may contain account numbers, internal dashboards, private conversations, anything that happened to be on your screen — leave your machine by design.
OpenCapture doesn't have a server to send anything to. The manifest
requests no host_permissions and no static content script; capture code
is injected on demand, only into the tab you click the icon on, and every
image stays in the browser's own storage until you explicitly download,
copy, or annotate it.
- Three capture modes — full page (auto-scroll + stitch, pixel-exact across device pixel ratios), visible viewport only, or a hand-dragged region.
- Annotate before you export — crop, arrow, rectangle, text, and a genuinely irreversible mosaic blur (not a cosmetic CSS filter — the source pixels are gone), each with full undo.
- Watermark tool — tile your own text and/or logo across the top, bottom, both, or the entire page, at 0° or a 45° slant. This is a tool you apply to your own exports for your own branding — OpenCapture never stamps anything onto your screenshots itself. The one paid part of OpenCapture: a one-time, 1000-credit Supporter unlock. Every other feature — capture, crop, arrow, rectangle, text, blur, PNG/PDF export — is free with no account at all.
- Export PNG or PDF — PDF pages are sized in points to match CSS pixels, so they print at true 1:1 physical size.
- Copy to clipboard, configurable save folder/filename, and a capture that survives the background service worker being evicted mid-flow.
- Chrome, Edge and Firefox, same source tree, two build targets.
| OpenCapture | GoFullPage | FireShot | Awesome Screenshot | |
|---|---|---|---|---|
| Free tier covers | Everything but watermarking | Capture and export only editing needs Premium |
Capture and export only editing needs a Pro licence |
100 captures basic annotation |
| Blur private details | Free | Paid | Paid | Free |
| Watermarking | Paid | No | Paid | Beta |
| Billing | One-time | Subscription | Annual or one-time | Subscription |
| Price | US$5 once, never expires | From $1/month billed annually |
$39.95/year or $99.95 once |
From $6/month Basic plan |
| Firefox | Yes | No | Yes | Yes |
| Open source | Yes AGPL-3.0-or-later |
MIT up to 2018 private branch since |
No | No |
Every figure is checked against that product's own site or store listing. Last reviewed August 2026 — tell us if something is out of date.
Full comparison, including where each one is the better pick →
| Browser | |
|---|---|
| Chrome | Chrome Web Store |
| Edge | Microsoft Edge Add-ons |
| Firefox | Firefox Add-ons |
Also on opencapture.app.
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Published and feature-complete: full-page, visible-area and selected-region capture, crop/annotate/watermark, and PNG/PDF export all work today, on all three stores.
To run a local build instead — for development, or for Android — see docs/LOCAL_TESTING.md, docs/FIREFOX_TESTING.md and docs/MOBILE_TESTING.md.
# prerequisites: Rust (stable) + wasm32-unknown-unknown target, Node 22.x,
# wasm-bindgen-cli pinned to exactly 0.2.100 (must match Cargo.toml)
rustup target add wasm32-unknown-unknown
cargo install wasm-bindgen-cli --version 0.2.100 --locked
cd apps/extension
npm install
npm run build # -> dist/ (load unpacked in Chrome)
npm run build:firefox # -> dist-firefox/ (load temporarily in Firefox)Then in Chrome: chrome://extensions → enable Developer mode → Load
unpacked → select dist/. In Firefox: about:debugging#/runtime/this-firefox
→ Load Temporary Add-on → select any file inside dist-firefox/.
Full walkthroughs, including the shared-mount build gotcha and what to manually click through, are in docs/LOCAL_TESTING.md, docs/FIREFOX_TESTING.md, docs/MOBILE_TESTING.md, and docs/TESTING_GUIDE.md.
Rust does every pixel operation; TypeScript is the browser-API shell around it.
crates/shot-core— scroll-target planning, gap/overlap-free slice stitching, PNG decode/stitch/encode, multi-page PDF export, oversized- canvas splitting. Compiles natively and towasm32-unknown-unknownviawasm-bindgen.crates/shot-qa— native CLI for PNG/PDF structural inspection, hashing, and pixel sampling/diffing.apps/extension— the MV3 shell (TypeScript, Vite): background service worker orchestrates capture, an on-demand content script handles DOM/lazy-load/sticky-element prep, and the popup/editor pages are plain canvas-based TypeScript.
Full milestone-by-milestone history and design rationale is in PLAN.md.
OpenCapture never requires an account for any capture, annotation, or export feature — everything above works fully offline. An optional OpenApps sign-in exists in the popup for a possible future paid tier (a larger/remote feature that isn't implemented yet); declining it changes nothing about the extension's core functionality.
AGPL-3.0-or-later. If you build on this code and offer it as a network service, the AGPL requires you to make your source available to that service's users too.