Custom Attributes

New featureSDK v0.3.11

Custom attributes on appointments

Custom booking frontends can now attach arbitrary data to an appointment at creation time — a booking source, a party size, an external reference id, or small JSON strings. Custom attributes are a flat map of string keys to string values (the same idea as Shopify order note/custom attributes): no data types, no access rules, not searchable — just a simple bag of key-value pairs that travels with the appointment.What’s in the release:

POST /storefront/appointments accepts an optional customAttributes object — a map of string keys to string values.
Appointment responses now echo customAttributes.
The merchant dashboard shows custom attributes on the appointment detail page.

Key behaviors:

Keys and values are always strings (a value can itself be a JSON string — it is stored verbatim and never parsed).
Limits: up to 250 attributes per appointment, keys up to 255 characters, values up to 5000 characters.
Not searchable by design — attributes are stored inline with the appointment for fast reads, not indexed for querying.

SDK support — available in @opencals/storefront-sdk v0.3.11 and higher. CreateAppointment gains an optional customAttributes field.

# Create an appointment with custom attributes
curl -X POST -H "X-Api-Key: sfk_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "slot": { "fromDate": "2026-08-15", "fromTime": "10:00:00", "toDate": "2026-08-15", "toTime": "11:00:00", "productId": "..." },
    "customAttributes": { "source": "widget", "party_size": "4" }
  }' \
  https://api.opencals.com/storefront/appointments

Releases

August 2026

June 2026

Custom attributes on appointments

​Custom attributes on appointments

Custom attributes on appointments