Licensing and attribution
The public holidays shown on our calendar pages and served by the holidays API come from a dataset we derive from openly licensed sources. This page states the license, the required attribution, and what the license asks of anyone who reuses the data.
Licensing and attribution sections
The dataset is licensed CC BY-SA 3.0
Our derived holiday dataset -- the holiday dates, rules, and names served by this site -- is distributed under the Creative Commons Attribution-ShareAlike 3.0 Unported license (CC BY-SA 3.0): http://creativecommons.org/licenses/by-sa/3.0/.
Where the data comes from
Holiday dates and rules are derived from date-holidays 3.37.0 (https://github.com/commenthol/date-holidays), whose data is licensed CC BY-SA 3.0, and were cross-validated at seed time against Nager.Date (https://github.com/nager/Nager.Date), which is MIT-licensed. Provenance is deliberately two-tier: the six launch countries (United States, United Kingdom, Ireland, Canada, Australia, New Zealand) are hand-verified against official government sources, while the remaining 60+ countries are served from the date-holidays + Nager.Date cross-validation above. Hand-verified corrections by this project are our own contribution.
Attribution (required notice)
Holiday dates derived from date-holidays (data licensed CC BY-SA 3.0), cross-validated against Nager.Date (MIT), with hand-verified corrections by this project. Derived dataset licensed CC BY-SA 3.0.
What the license obligates of reusers
If you copy, redistribute, or adapt this dataset, CC BY-SA 3.0 requires you to (1) attribute the source with the notice above, (2) distribute adaptations under this same CC BY-SA 3.0 license (ShareAlike), and (3) indicate if you changed the data. You may use the dataset for any purpose, including commercially, but you cannot impose additional restrictions on downstream recipients.
How we comply
Attribution travels with the data at every exposure: /api/holidays payloads carry the license name and this attribution URL, and country calendar pages link their data source. This page is the canonical attribution home for the dataset.
Typefaces
The template collection page uses two typefaces derived from the URW Base 35 fonts project, which is licensed under the GNU Affero General Public License v3 with a font embedding exception: P052 (served as "Paper Serif", roman and italic) and Nimbus Sans (served as "Studio Sans", regular and bold). Upstream source: https://github.com/ArtifexSoftware/urw-base35-fonts. The fonts were subset to the glyphs this site uses and converted to WOFF for web delivery; no other changes were made. The complete license text ships alongside the font files, and the fonts load only on the /templates page.