Most Hebcal content is licensed under a Creative Commons Attribution 4.0 International License (sometimes referred to as “CC BY 4.0”). If you use Hebcal.com content or APIs, continue reading to understand what privileges this license grants and how you can give appropriate credit to Hebcal.
The CC BY 4.0 license is designed to encourage use and reuse of content. You can remix, transform, and build upon the material for any purpose, even commercially. You need not ask for permission, notify us about the usage, or send us money. This license gives you permission to freely to copy and redistribute the material in any medium or format as long as you give appropriate credit to Hebcal.com.
Creative Commons licenses have a flexible attribution requirement, so there is not necessarily one correct way to provide attribution. The proper method for giving credit will depend on the medium and means you are using, and may be implemented in any reasonable manner.
On a website, you might include a short piece of text with a link back to Hebcal.com, e.g.:
Powered by Hebcal Shabbat Times
Or you might include the following at the bottom of a printed page or refrigerator magnet:
Jewish holidays and candle-lighting times are provided by Hebcal.com with a CC BY 4.0 International License.
Creative Commons publishes best practices for attribution which includes some good (and not so good) examples of attribution.