Omnisend

Omnisend is purpose-built for ecommerce lifecycle email — abandoned cart, order confirmation, product browse abandonment, post-purchase sequences. Its API reflects this: contacts are enriched with order events and custom properties, and automation triggers fire on commerce events. For agents in ecommerce contexts: sync customer + order data, trigger purchase lifecycle automations, and manage segments. Shopify integration is native; direct API works for any ecommerce stack. Confidence is docs-derived.

REST API at api.omnisend.com/v3. Resources: contacts, events, orders, campaigns, lists. POST /contacts creates/updates a contact ({email, firstName, lastName, status, customProperties: {...}, sendWelcomeEmail}). POST /events tracks a custom event for a contact. POST /orders creates an order event (triggers order-based automations). GET /campaigns lists email/SMS campaigns. GET /contacts retrieves contacts with filter options. Response: JSON.

API key auth: X-API-KEY: {api_key} header. Keys from Omnisend account → Account → API keys. Store-scoped key. HTTPS enforced. No OAuth2. Rate limiting: 400 requests/minute. Key rotation via Omnisend account settings.

Standard HTTP status codes with JSON error bodies. 401 for invalid key, 422 for validation errors, 429 for rate limit. Contact upsert: updates existing contact if email matches. Order events trigger automation flows asynchronously. Campaign send scheduling via campaign settings. Omnisend uptime at status.omnisend.com.

api-docs.omnisend.com provides REST API reference with request/response examples. Getting started requires an Omnisend account (free trial). SDKs: Node.js (unofficial). Postman collection available. Strong for ecommerce teams; less suited for general-purpose email marketing. Community via Omnisend support.