Campaign Monitor API
Campaign Monitor publishes a self-serve REST API at api.createsend.com covering campaigns, lists, subscribers, transactional email, and webhooks. Auth is OAuth 2.0 or a per-account API key with no partner approval. Transactional endpoints are capped at 1 request per second per account.
Frequently asked questions
Campaign Monitor scores A on the API Report Card. Campaign Monitor publishes a self-serve REST API at api.createsend.com covering campaigns, lists, subscribers, transactional email, and webhooks. Auth is OAuth 2.0 or a per-account API key with no partner approval. Transactional endpoints are capped at 1 request per second per account.
Campaign Monitor has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
Campaign Monitor is a cloud-based email marketing and marketing automation platform that lets brands design, send, automate, and analyze email (and increasingly SMS) campaigns through a drag-and-drop editor, a visual customer-journey builder, list segmentation, personalization, transactional email, and analytics dashboards.
Vertical: Email marketing / marketing automation (horizontal SaaS, not industry-specific). Marketers import subscriber lists (or sync them from CRMs, ecommerce platforms, and forms), build branded HTML emails in the drag-and-drop designer, segment audiences by demographics and behavior, and either send one-off campaigns or wire subscribers into visual customer journeys triggered by signup, purchase, link click, date, or custom API events.
Campaign Monitor has been in market for ~22 years and has historically served 250,000+ customers across 190+ countries, with a long-standing presence on G2, Capterra, Software Advice, and most 'best email marketing platform' roundups.
Yes, for any brand running its email program on Campaign Monitor, the platform is the system of record for the full email engagement dataset: the complete subscriber database with custom fields and consent state, every list and segment definition, every campaign send with per-recipient open/click/bounce/unsubscribe/spam history, every journey and the entry/exit history of every subscriber through it, all transactional message logs, every webhook event stream, template assets, and (for ecommerce-connected accounts) revenue attribution.
Founded 2004 in Sydney, Australia by Ben Richardson and David Greiner as a self-funded design-led email tool, with no outside funding until 2014 when the company took a $250M minority investment from Insight Venture Partners.
Rate limit on transactional endpoints is 1 request per second per account, very low for any production transactional workload, and lifts require contacting support. API has been stuck on v3.x for years (3.2 to 3.3 was a minor revision); no signaled v4 and uneven endpoint modernization. Full sourced list under Sources below.
Common alternatives include Mailchimp (Intuit), Klaviyo, Constant Contact, HubSpot Marketing Hub, ActiveCampaign, Brevo (Sendinblue). Graded alternatives appear under "More from the report card" below.
Grades measure one thing: can a customer's engineering team get their own data out programmatically? We check six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and roll them into a letter grade. Grades get re-verified, and they only move on evidence.