Sync EHR availability

Mirror doctor shifts from a 3rd-party EHR into a Cal.com schedule with a small sync microservice and the schedules API.

3rd-party

EHR systemEpic, Cerner, Athena, etc. Source of truth for shifts and PTO.

Pull shifts (cron / webhook)

Yours

Your sync microserviceGET https://ehr.example.com/api/shifts/:doctorId

Diff against current Cal.com schedule

Yours

Compute date overridesOff-duty days → { date, startTime: '00:00', endTime: '00:00' }

PATCH /v2/schedules/:scheduleId

Cal.com

Cal.com scheduleOverrides applied — blocked dates roll out instantly.

Bookers see updated availability

Cal.com

Booker UIOff-duty days are greyed out for patients.

Sync microserviceruns on cron — every 15 min

// Pull shifts from the EHR and mirror them into a Cal.com schedule
async function syncDoctorAvailability(doctorId, scheduleId) {
  // 1. Pull shifts from the EHR
  const shifts = await ehrFetch(`/api/shifts/${doctorId}`);
  // → [{ date: "2026-05-12", offDuty: true }, …]

  // 2. Off-duty days → zero-length availability windows
  const overrides = shifts
    .filter((s) => s.offDuty)
    .map((s) => ({
      date: s.date,
      startTime: "00:00",
      endTime: "00:00",
    }));

  // 3. Push overrides to Cal.com — partial PATCH, only sends what changed
  await fetch(`https://api.cal.com/v2/schedules/${scheduleId}`, {
    method: "PATCH",
    headers: {
      "Authorization": `Bearer ${CAL_API_KEY}`,
      "cal-api-version": "2024-06-11",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ overrides }),
  });
}

GET /v2/schedules/:id reads the current schedule so you can diff before writing. PATCH /v2/schedules/:id accepts a partial body — send just overrides to mark days off without touching the recurring weekly availability.