"What time works for everyone?" is a surprisingly hard question to answer in code. You have to read each person's calendar, line up the busy blocks, respect working hours and time zones, leave buffer time between meetings, and only then find the gaps everyone shares. The Nylas Availability API does all of that in one request: hand it a list of participants and a window, and it returns the time slots that actually work.
This post covers finding meeting times from two angles: the HTTP API for your backend, and the nylas CLI for the terminal. I work on the CLI, so the terminal commands below are the ones I reach for when I'm checking a calendar.
Availability versus Free/Busy
There are two endpoints here, and picking the right one saves you work. The Availability endpoint finds bookable slots across a group of participants, applying working hours, buffers, and meeting duration to return times you can actually book. Free/Busy is simpler: it returns the raw busy blocks for one or more email addresses over a window, leaving the slot math to you.
Reach for Availability when the question is "when can these people meet?" and you want the answer as a list of open slots. Reach for Free/Busy when you only need to see when calendars are busy, for example to gray out times in a custom UI. Availability is a POST /v3/calendars/availability, an application-level call that takes participants by email, while Free/Busy is grant-scoped at POST /v3/grants/{grant_id}/calendars/free-busy. This post focuses on Availability, since that's the one that answers the scheduling question directly.
