Find the best promotion for a cart
Return the single highest-value eligible promotion for a cart — what to auto-apply at checkout. Galactic Core evaluates every active promotion against the cart server-side and returns the one that saves the customer the most, along with its discount amount.
Send the cart you intend to charge — each line is the product, its quantity, and
the unit price you’re charging. When no promotion applies, promotion is
null and discount is 0.
Marketplace storefronts: pass store_id (the merchant_store_id you
received with the promotion or collection) to evaluate that merchant’s
promotions.
Authorizations
API Key Authentication
Use your API key in the Authorization header:
Key Types:
Secret Keys (Server-Side Only):
- Format:
tybrite_sk_live_*(production) ortybrite_sk_test_*(sandbox) - Full read/write access to all endpoints
- ⚠️ NEVER expose in client-side code or public repositories
- Required for: write operations, authentication, payment verification, AI recommendations
Publishable Keys (Client-Safe):
- Format:
tybrite_pk_live_*(production) ortybrite_pk_test_*(sandbox) - Read-only access (GET requests only, plus POST semantic search)
- ✅ Safe for client-side JavaScript, mobile apps, and public code
- Allowed for: browsing products, search, CMS content, pricing queries
Endpoint-Specific Requirements:
- Authentication endpoints (
/v1/auth/*): Secret key required - Payment verification (
POST /v1/payments/verify): Secret key required - AI Recommendations (
POST /v1/recommendations): Secret key required - Semantic Search (
POST /v1/search): Both key types allowed (read-only operation) - All write operations: Secret key required
- All read operations: Both key types allowed
Using a publishable key for restricted operations returns 403 Forbidden.
Query Parameters
The merchant whose promotions to evaluate. Required for marketplace
storefronts — pass the merchant_store_id you received with the promotion
or collection. Ignored for single-store keys.

