AddBusinessDays API
The business-day engine behind this site, as a JSON API. 200+ countries, states/regions, observed holidays and custom weekends.
| Add business days | /api/v1/add-business-days?country=US&date=2026-12-23&days=3 |
| Count business days | /api/v1/business-days-between?country=GB&start=2026-12-01&end=2026-12-31 |
| Is it a business day? | /api/v1/is-business-day?country=DE&state=BY&date=2026-10-03 |
| Holidays by year | /api/v1/holidays?country=CA&year=2027 |
| Countries & states | /api/v1/countries |
Plans from free (500 requests/month) to 1,000,000 requests/month. Keys and billing are handled by RapidAPI.