Sendpulse

SendPulse is a multi-channel platform — email, SMS, web push, Viber, and chatbot campaigns from one account. For agents that need to span multiple messaging channels from a single API integration, this breadth is an advantage over single-channel ESPs. Core email API covers mailing list management, campaign creation, and autoresponders. OAuth2 auth adds a token-refresh step compared to simple key-based providers. Confidence is docs-derived.

REST API at api.sendpulse.com. Resources: mailing-lists, emails, campaigns, senders. POST /mailing-lists creates a list. POST /addressbooks/{id}/emails adds subscribers. POST /emails sends a campaign ({task_name, sender_name, sender_email, subject, body, list_id}). GET /campaigns lists campaigns with stats. OAuth2 token required for all calls. Multi-channel: SMS via /sms, web push via /push-notification endpoints.

OAuth2 client credentials: POST /oauth/access_token with client_id + client_secret. Bearer token in Authorization header. Token expires in 3600 seconds — agents must refresh. Client credentials from SendPulse account → API → API keys. HTTPS enforced. No simple API key option — OAuth2 is required.

Standard HTTP status codes with JSON error responses. 401 for expired/invalid token, 400 for validation errors. Campaign send: async (status tracked by campaign ID). Token expiry is the primary operational concern — implement automatic refresh. SendPulse uptime at sendpulse.com/status.

sendpulse.com/integrations/api provides REST API reference. OAuth2 flow documented. Getting started requires creating a SendPulse account (free tier available) and registering an API application. Community via SendPulse support. Less comprehensive developer documentation than Mailchimp or SendGrid.