Paste a price (any currency), see what it could buy in high-impact charity. Ships in three shells from one shared codebase: a web converter, a drag-to-bookmarks bookmarklet, and a Chrome MV3 extension.
The Chrome extension annotates Amazon prices with a small chip + a hover card showing the charity, the math, the cost basis, and the round-up jar status. Click to land on a 1-click donation page with the amount already filled.
| Extension popup charity dropdown, round-up jar progress, pause, per-site toggle |
Web converter paste any currency, see impact across all four charities |
Options page — full charity list, round-up threshold, history table, opt-in purchase prompt
| Phase | What | Where | State |
|---|---|---|---|
| 0 | Charity data + math + currency parser + static FX + round-up math | packages/charities |
shipped |
| 1 | Web converter UI (any currency input, drag-link to bookmarklet) | apps/web |
shipped |
| 2 | Bookmarklet (Amazon TLDs, MV3-safe IIFE, hover card) | apps/bookmarklet |
shipped |
| 3 | Chrome MV3 extension (round-up jar, history, share, purchase prompt) | apps/extension |
shipped |
CI runs lint, typecheck, test, and build on every push and PR. 169 tests across three workspaces.
Cost figures are GiveWell-derived approximations. FX rates are January
2025 ballparks. Both have asOf fields and TODO(oliver) markers for
a pre-launch verification pass.
apps/
web/ Next.js converter — paste a price, see all charities
bookmarklet/ IIFE bundle → drag-to-bookmarks UX (builds into web/)
extension/ Chrome MV3 manifest + content script
packages/
charities/ Validated reference data: charities, FX rates,
parsePriceString, convertPrice, formatUnits
docs/
architecture.md How the four workspaces talk to each other
mv3-csp.md Why we ship a single self-contained bundle
Requires Bun 1.3+.
bun install
bun run dev # boots apps/web on http://localhost:3000
bun run typecheck # all workspaces
bun run lint # all workspaces
bun run test # all workspaces (Vitest)
bun run build # apps/web (bookmarklet bundle regenerates first)The bookmarklet bundle (apps/web/src/generated/bookmarklet.ts) is
gitignored and regenerated by the root prebuild / predev /
pretypecheck hooks.
bun --filter '@price-to-impact/extension' run buildThen in Chrome: chrome://extensions → enable "Developer mode" →
"Load unpacked" → pick apps/extension/dist/.
| Task | File |
|---|---|
| Add a charity | packages/charities/src/index.ts |
| Add a currency | packages/charities/src/parsePrice.ts + src/fx.ts |
| Add a site detector | apps/bookmarklet/src/detectors/<site>.ts |
| Change pill style | apps/bookmarklet/src/render.ts |
| Tweak web UI | apps/web/src/app/page.tsx |
| Extension logic | apps/extension/src/content.ts |
See docs/architecture.md for the full data
flow and the two contracts that hold it together.
A Habitual Genesis project. Released under MIT. Contributions welcome — see CONTRIBUTING.