Changelog - Opencals Developer Docs

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June 2026

Add-Ons — new feature

Service businesses can now attach optional extras to any bookable service. Customers select add-ons during the booking flow — after picking a service and time slot, before checkout — and pay the combined total in one transaction. What’s in the release:

GET /storefront/add-ons — list add-ons, filter by productId
GET /storefront/products/:id/add-ons — add-ons for a specific service
POST /storefront/cart/add-ons — add an add-on to a cart item
PATCH /storefront/cart/add-ons/:id — update quantity
DELETE /storefront/cart/add-ons/:id — remove from cart

Key behaviors:

Add-ons are scoped to products. Only add-ons linked to the booked service appear.
Two pricing modes: fixed (customer picks quantity) and duration-multiplied (quantity auto-set to the number of duration units, useful for per-day or per-hour charges).
Prices are snapshotted at cart creation — later catalog changes don’t affect existing orders.
Add-ons appear in order line items (OrderAddOnLineItem) and on appointment records (AppointmentAddOn). Partial quantity refunds are supported.
Works on both platform='opencals' and platform='shopify'.

# List add-ons for a service
curl -H "X-Api-Key: sfk_your_key" \
  https://api.opencals.com/storefront/products/{productId}/add-ons

# Add to cart
curl -X POST -H "X-Api-Key: sfk_your_key" \
  -H "X-Cart-Id: {cartId}" \
  -H "Content-Type: application/json" \
  -d '{"cartItemId": "...", "addOnId": "...", "quantity": 1}' \
  https://api.opencals.com/storefront/cart/add-ons

See the Add-Ons feature page for the full overview and use cases.

Developer docs launched

The Opencals developer documentation is now live at opencals.com/docs.

Interactive API Reference with an in-browser playground — try every endpoint without leaving the docs
Quickstart guide — first API call in under 5 minutes
Build a booking page — end-to-end tutorial (services → staff → availability → cart → checkout)
TypeScript SDK guide — typed client with Zod schemas and formatting helpers
Webhooks overview — planned event catalog for appointment and order lifecycle events
Open-source templates — production-ready booking site starters

Storefront API — v1

The Storefront API is now publicly available. It covers the full customer-facing booking flow:

Domain	Key endpoints
Products	List services, collections, variants
Staff members	List staff, per-staff availability
Locations	Multi-location support
Appointments	Real-time slot availability
Cart	Create and manage a booking cart
Checkout	Initiate and confirm checkout
Payments	Stripe-backed deposits and full payments
Customer self-service	View, reschedule, and cancel bookings
Webhooks	Signed event delivery (coming soon)

Base URL: https://api.opencals.com · Authentication: Authorization: Bearer sfk_… See the full endpoint catalog.

Storefront SDK — v0.2.0

@opencals/storefront-sdk is the official TypeScript client for the Storefront API.

npm install @opencals/storefront-sdk

Generated from the OpenAPI spec — every request and response is fully typed
Zod schemas for runtime validation
Formatting helpers for prices, durations, and timezones
MIT licensed

npm ↗ · SDK guide

Haar — open-source salon booking template

The first open-source Opencals template is live. Haar is a complete beauty-salon booking website built on the Storefront API: service catalog, staff and multi-location booking, real-time availability, Stripe checkout, and customer accounts.

Stack: Next.js 15, TypeScript, Tailwind, @opencals/storefront-sdk
MIT licensed — clone, rebrand, deploy for yourself or clients
One-click Vercel deploy

Live demo ↗ · GitHub ↗ · Template docs

​June 2026

​Add-Ons — new feature

​Developer docs launched

​Storefront API — v1

​Storefront SDK — v0.2.0

​Haar — open-source salon booking template