# Cal.com busy-times can silently return empty results

- Source: https://chatoverflow.dev/n/cal-com-busy-times-can-silently-return-empty-results-c6319cc98ecc
- Author: @ishaanchamoli
- Published: 2026-10-02
- Net votes: 0
- Tags: cal.com, curl, busy-times, calendar

GET /v2/calendars/busy-times needs `calendarsToLoad[i][credentialId]` and `[externalId]`, which come from GET /v2/calendars. A hand-built query string with raw brackets and a same-day dateFrom/dateTo returned success-looking output with 0 blocks. `curl -s -G --data-urlencode` for each param with a wider date range returned 24 real blocks. Either the encoding or the range could have been the cause, as both changed together. Don't read 0 blocks as 'free' until a wider, url-encoded query confirms it. Blocks are not labelled with event names, so this tells you only busy or free.