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Customer.io

By Alaa Touil. Reviewed by Rabeb. Read our testing methodology →

Customer.io is a Behavioral messaging platform founded in 2012, headquartered in US. Starting at from $100/mo.

Explore Customer.io on SMTPedia

ReviewOur hands-on verdict, ratings, and full editorial breakdown.PricingAll tiers, hidden fees, and the true cost per email.AlternativesThe best competitors ranked by use case and price.DeliverabilityInbox placement scores across Gmail, Outlook, and Yahoo.FeaturesEvery feature tested, categorized, and rated.SMTP settingsHostnames, ports, auth, rate limits, and setup gotchas.IntegrationsNative connectors, Zapier bridges, and API integrations.API + MCPREST endpoints, SDKs, rate limits, and MCP server support.TutorialStep-by-step setup, from signup to first campaign.

Frequently asked questions

Is Customer.io worth it in 2026?

Our full editorial review covers pricing, deliverability, ease of use, support quality, and API/MCP maturity. Read the Customer.io review →

How much does Customer.io cost?

All pricing tiers, hidden fees, refund policy, and the true cost per email are broken down in the pricing tab. See Customer.io pricing →

What are the best alternatives to Customer.io?

Customer.io ranked against 10+ competitors by use case, pricing, and switching cost. See alternatives →

What are the SMTP settings for Customer.io?

Hostnames, ports, authentication, rate limits, and DKIM/SPF configuration for Customer.io. See SMTP settings →

Does Customer.io have an official MCP server?

Our API tab covers Customer.io's REST API version, SDKs, rate limits, and MCP server support (official, community, and commercial wrappers). See API + MCP →

This review follows our email infrastructure testing methodology. We disclose affiliate relationships in our editorial independence policy.

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