Privacy & network
Local-first by design: what stays on your Mac, and the only two requests Numlex ever makes.
Numlex is local-first. Your sheets, variables, constants and settings live on your Mac; the app makes exactly two kinds of network requests, both in the background and both optional to your calculations.
What stays local
- All calculations, dates, variables, sections, totals and unit conversions run entirely on your machine and work fully offline.
- Sheets and settings persist in
~/Library/Application Support/Numlex(a single local JSON store). - There is no account, no sign-in, and no cloud sync of any kind.
- Numlex never reads GPS or location data.
The only network requests
| Request | Why | What is sent |
|---|---|---|
| Currency-rate refresh | Live fiat rates for … to EUR lines | Nothing identifying — a public rate-table fetch |
| Weather lookup | weather in <city> lines | Only the city name you typed |
- Currency rates come from the free open.er-api.com service (no API key). They are cached locally for an hour with an 8-second timeout; when offline, the last good table keeps serving.
- Weather goes to Open-Meteo (no key, no location permission). Only the explicit city you typed is sent — never your position. Readings are cached for ten minutes.
If the network is unavailable, every line keeps working from cached values or, for pure calculations, from nothing at all. A flaky connection never blanks a sheet.
What Numlex does not do
No analytics, no telemetry, no crash reporting, no ad or tracking calls, and no data leaving your Mac beyond the two requests above. There is no server to send data to — there simply is no backend.