Help / API

/v1/slots

Read-only availability surface. Use list for "show me everything in a window" and check for "is this exact time still bookable?".

GET /v1/slots

List available slots for an event type over a window.

Query parameters

Response

{
  "data": {
    "event_type_id": "01HXXX…",
    "timezone": "Europe/London",
    "computed_at": "2026-05-14T09:00:00.000Z",
    "slots": [
      { "start": "2026-05-20T10:00:00.000Z", "end": "2026-05-20T10:30:00.000Z", "available": true },
      { "start": "2026-05-20T10:30:00.000Z", "end": "2026-05-20T11:00:00.000Z", "available": true }
    ]
  },
  "meta": { "request_id": "req_…" }
}

• All slots returned have available: true; busy times are simply omitted.
• slots[].start / end are ISO 8601 in UTC.
• computed_at is the server time the result was generated, useful for detecting staleness between list and create.

curl

curl -H "Authorization: Bearer $TOKEN" \
  "https://api.42min.us/v1/slots?event_type_id=01HXXX…&start=2026-05-20T00:00:00Z&end=2026-05-21T00:00:00Z&timezone=Europe/London"

Common errors

• 400 invalid_query_param: start/end missing, malformed, or window longer than 31 days.
• 404 event_type_not_found: unknown id/slug or wrong account.

GET /v1/slots/check

Check whether a specific slot is bookable right now.

Query parameters

Response

Slot is available:

{
  "data": { "available": true, "duration_minutes": 30 },
  "meta": { "request_id": "req_…" }
}

Slot is not available, and reason tells you which check failed:

{
  "data": {
    "available": false,
    "reason": "slot_busy",
    "next_available": "2026-05-20T11:00:00.000Z"
  },
  "meta": { "request_id": "req_…" }
}

Possible reason values:

next_available is a best-effort lookup of the next free slot within 7 days after the requested end. It may be null.

curl

curl -H "Authorization: Bearer $TOKEN" \
  "https://api.42min.us/v1/slots/check?event_type_id=01HXXX…&start=2026-05-20T10:00:00Z"

Common errors

• 400 invalid_query_param: start missing or invalid, or end not after start.
• 404 event_type_not_found.

When to use which

• Listing a calendar UI → GET /v1/slots. One round-trip per visible range; cache for a few seconds.
• Just before creating a booking → GET /v1/slots/check. Combine with the Idempotency-Key'd POST /v1/bookings to handle the race when the slot is taken between check and create.