Releases and changes

The data is published in releases. Every response names the release that answered it, in data_release and the x-data-release header, so you can tell whether two answers came from the same data.

GET /v1/changes lists the dates each release added, removed or modified, oldest first. A date becoming verified counts as modified.

# Everything that changed since 1 October 2026
curl -H "Authorization: Bearer $FC_API_KEY" "https://api.financecalendarapi.com/v1/changes?since=2026-10-01"

# Only your calendars, since the release you last saw
curl -H "Authorization: Bearer $FC_API_KEY" "https://api.financecalendarapi.com/v1/changes?since=20261013T021036Z&calendars=XNYS,USD"

Each change has the release, when it was published, the calendar, the date, whether it was added, removed or modified, and the entry before and after. Pages hold up to limit changes (default 100, at most 1,000); pass the response’s next_cursor as cursor for the next page.

Poll it daily, or after each release, to keep a local copy of the calendars you use up to date. The What changed tool shows the same feed in the browser.