Level 2b — Calendar Unavailabilities

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Go back to the main guide here: https://docs.nexhealth.com/docs/scheduling-configuration-guide#/

In Happy Smiles Dental - Configuration 2 you saw that lunch is modeled as the absence of a working hour. There is a 9:00 - 12:00 working hour, a gap in between, and a 1:00 - 5:00 working hour. That's one way to make time unbookable. There's another way to do this.

Practices can place dedicated calendar unavailabilities (often called events or blocks) on the schedule. These are discrete blocks of time on a provider's calendar that mark the time slot as unavailable and are configured directly in the target health record system.

Instead of splitting a working hour record, the office adds a block onto the calendar (a staff meeting, a team huddle, a recurring admin hour) and the Synchronizer API treats that block as an unavailable appointment. The slot is automatically excluded from /available_slots.

The Synchronizer API returns these blocks as an unavailable appointment (unavailable is true) through the /appointments endpoint as they are scheduled breaks on the calendar.

Example response from /appointments:
Response (trimmed)

{
  "code": true,
  "description": null,
  "error": null,
  "data": {
    "id": 1484450509,
    "patient_id": null,
    "provider_id": null,
    "provider_name": null,
    "start_time": "2026-07-07T16:00:00.000Z",
    "end_time": "2026-07-07T17:00:00.000Z",
    "unavailable": true,
    "cancelled": false,
    "location_id": 21241,
    "foreign_id": "block_47",
    "foreign_id_type": "remote_db-opendental-DataSource-9326",
    "misc": {},
  },
  "count": null
}

Two fields are the markers:

• patient_id is null - no patient is associated with the block
• unavailable is true - the slot is explicitly marked as unbookable

When /available_slots derives bookable time, it filters out any window that overlaps with a record where unavailable: true. You don't need to filter these out yourself.

This concept is source-agnostic. Calendar unavailabilities exist whether the practice uses manual or synced configuration.

Dentrix

For Dentrix event blocks are recognized as calendar unavailabilities.

Open dental

For Open dental non-scheduling blockouts and holidays are recognized as calendar unavailabilities.

Eaglesoft

For Eaglesoft, closed chairs (enabled upon configuration request) and time blocks are recognized as calendar unavailabilities.