# Licenses & Attribution

PowerZmanim relies on data and software from several sources. This page lists all of them.
See also [`/methodology.html`](/methodology.html) for how each is used.

## kosher-zmanim (halachic time calculation engine)

Every halachic time this site displays is computed with **kosher-zmanim**, a JavaScript/TypeScript
port of the [KosherJava Zmanim API](https://github.com/KosherJava/zmanim).

- **Package:** [`kosher-zmanim`](https://www.npmjs.com/package/kosher-zmanim) on npm
- **Repository:** <https://github.com/BehindTheMath/KosherZmanim>
- **License:** [GNU Lesser General Public License v3.0 (LGPL-3.0)](https://www.gnu.org/licenses/lgpl-3.0.html)

kosher-zmanim is used as an unmodified dependency (installed via npm, not vendored or forked), and
its own license headers and notices are left intact. Because it is consumed as a library rather
than statically linked into a way that would trigger LGPL's stricter provisions, PowerZmanim's own
code may remain under its own license (see below) — but the LGPL-3.0 text governs kosher-zmanim
itself, and anyone redistributing or modifying kosher-zmanim must comply with it independently of
PowerZmanim's license. Full license text: <https://www.gnu.org/licenses/lgpl-3.0.html>.

## Hebcal (calendar data & cross-check)

Hebrew calendar data, holiday and fast-day information, parashat hashavua, and location-aware
candle-lighting/havdalah values come from the [Hebcal](https://www.hebcal.com/) API. Every
halachic time this site computes is also independently cross-checked against Hebcal's own
zmanim calculation as a second, separately implemented source.

- **Source:** <https://www.hebcal.com/>
- **License:** [Creative Commons Attribution 4.0 International (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/)

Per the CC BY 4.0 terms, Hebcal is credited on every page of this site that uses its data
(see the site footer) and here.

### GeoNames & MaxMind (location data behind Hebcal)

Hebcal's geographic and timezone lookups are themselves built on data from:

- [GeoNames](https://www.geonames.org/) — see [GeoNames terms of use](https://www.geonames.org/export/)
- [MaxMind](https://www.maxmind.com/) — see [MaxMind terms of use](https://www.maxmind.com/en/end-user-license-agreement)

Both are credited alongside Hebcal wherever Hebcal is credited on this site.

## PowerZmanim's own code

All application code in this repository — the engine adapter, the visual components (live sky
timeline, Zman Dial, Moon-Date, Machlokes Band), the UI kit, and the educational content — is original work by
PowerJews, released under the **MIT License**.

```
MIT License

Copyright (c) 2026 PowerJews

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```

This MIT license covers PowerZmanim's own source code only. It does not relicense kosher-zmanim
(LGPL-3.0) or Hebcal's data (CC BY 4.0) — each of those retains its own license as described above.

## A note on the halachic content itself

The educational text, citations, and degree/minute values in this app (see
[`/methodology.html`](/methodology.html) for the full registry) were cross-referenced against
[Halachipedia](https://halachipedia.com/) during development. This site is software, not a posek —
for any practical halachic question, consult your rav.