Customer.io

What Customer.io is

Customer.io is a customer engagement platform for lifecycle messaging: onboarding, activation, retention, win-back and cross-sell campaigns that fire from what people actually do in a product or store. The pricing page footer names the company behind it as Peaberry Software, Inc., and the About page gives 2012 as the founding year. The platform sends marketing email and transactional email, plus push notifications, in-app messages, SMS, WhatsApp and LINE, from one data model and one workflow builder. The pricing page says it is "Trusted by 9,000+ brands," and the About page lists more than 100 billion messages sent in 2025, over 12 billion daily API calls and 78k active users. The home page sums up the idea as unifying data, messaging and AI in one platform so that every customer interaction becomes a signal a team can act on.

What a sender gets

Data first. Everything runs on customer data you send in. The platform page promises "a flexible, real-time data foundation that adapts to your architecture, so journeys always run on the freshest data." You can sync from a data warehouse, connect unlimited sources and destinations, and build custom object relationships, so a message can reference an account, a subscription or an order rather than only a person. People attributes and monthly API calls are unlimited on every plan, and the pricing table lists reverse ETL, a data index, connected forms and privacy management for all tiers.

Audiences. Segments combine "profile data, events, and behaviors" and update in real time as data changes. The pricing page lists an AI-powered segment builder, suggested segments, nested data and ad audience sync on every plan, so the same segment that drives an email can be pushed to ad platforms.

Journeys. The workflow engine builds "multi-step journeys that respond to customer behavior in real time across email, SMS, push, in-app, and more." Workflows can be triggered from any customer event and branch across channels. Every plan includes the visual workflow builder, cross-channel campaign automation, send-time optimization, API-triggered broadcasts, LLM actions and custom SMTP. The home page frames the use cases as activation, retention, cross-sell and upsell, and onboarding welcome flows.

Design Studio. The email editor serves developers as well as marketers. It offers dual editors (drag-and-drop visual and code), and the Design Studio page lists "dark mode emulation, emmet, auto-complete, Can I Email data, and plain text support." Global Styles hold the color palette, font family, text styles and button formatting; reusable blocks can be customized with JavaScript; messages can be saved as templates and edited in a draft mode before going live. Version control, comments and a view of who else is editing support team work. Under the hood the editor supports MJML, runs a SpamAssassin check, and includes "Transformers" that minify, prettify and clean up unused CSS. The company says emails built there are lightweight "and come with reduced risk of Gmail clipping," and it integrates Deque University's accessibility rules to flag issues. The pricing table adds AI-generated global styles, an AI translator for messages and email content analysis on every plan.

The AI Agent. The platform page calls its approach "AI that’s built in, not bolted on." The Agent, currently marked beta on the pricing page, can build a journey from a description, build segments, draft and edit copy, and answer how a campaign is performing. The home page promises you can "go from a single prompt to a fully configured automation with triggers, content, timing, and logic." Plans differ in Agent session limits, custom execution skills (3 on Essentials, 10 on Premium) and scheduled "Routines."

Built for other AI tools too. The platform exposes an MCP server ("Connect Claude, Cursor, or any MCP-compatible tool directly to Customer.io"), a CLI for "AI coding assistants and automation scripts," and APIs and webhooks. Webhooks for sending and receiving are unlimited on all plans.

Analytics. Dashboards, campaign reporting, conversion tracking, survey analysis, data export, and A/B and multivariate testing come with every plan. The platform page puts the emphasis on outcomes: "Go beyond open rates. Connect every campaign to the business outcomes you care about."

Plans and prices

The pricing page publishes three plans.

• Essentials starts at $100 per month, billed monthly, "for teams getting started with data-driven messaging." It includes 5,000 profiles (people plus objects), 1 million emails per month, 2 object types, 2 workspaces, the AI Agent with core execution skills, the visual workflow builder, and email and community support. Extra profiles cost $0.009 each.
• Premium starts at $1,000 per month, billed yearly, "for teams scaling across channels with custom workflows." It adds custom profile and email volume and pricing, 10 object types, unlimited workspaces, higher Agent limits and custom skills, daily Routines, premium chat and email support, 90-day onboarding support, HIPAA compliance at additional cost, premium data integrations, anonymous messages, data warehouse destinations, data replay, custom role-based permissions and managed deliverability.
• Enterprise is priced by sales and adds the company's best pricing on profile and email volume, priority technical support, dedicated hardware, audit logging and data governance, and a shared Slack channel. Several support items are marked as additional cost.

On all three plans, user seats are unlimited, push and in-app messages are unlimited, and transactional email and mobile SDKs are included. Monthly SMS sends are custom on every plan. Additional email is $0.12 per 1,000 on every tier, and additional AI credits are $10 per 100K on Essentials and Premium. Essentials is billed monthly; Premium and Enterprise run on annual terms.

There is a "14-day free trial" with "No credit card required" and "Cancel anytime." Early-stage companies that have "raised under $10M" can apply to the Startup Program for "12 months of Customer.io free."

Security, data location and support

The security section of the pricing table lists SSO and two-factor authentication, US and EU data centers, SOC Tier II compliance and standard role-based permissions on every plan. Every page carries the badges GDPR, CCPA, ISO 27001, AICPA SOC and HIPAA; on the pricing table, HIPAA compliance is custom on Premium and Enterprise and not included on Essentials. The platform page states "99.98%" platform uptime and "24/5" global support coverage.

Support scales with the plan: documentation, community and email support for everyone; chat, onboarding, a dedicated customer success manager, migration help, a technical implementation specialist and a 2-hour first outreach response time from Premium up; a shared Slack channel on Enterprise.

Who it suits

Customer.io fits SaaS, app and ecommerce teams that already track events and want messages to follow behavior: a welcome flow that changes once a user completes setup, a win-back that fires on inactivity, an upsell tied to product usage. Unlimited seats make it comfortable for larger marketing and product teams, and the developer-friendly editor, MCP server and CLI suit teams with engineers involved. The published Essentials price makes it possible to start small.

A solo newsletter writer who just wants to send a weekly issue to a list would be paying for event-driven machinery they will not use, and SMS volume is priced on request rather than listed, so a text-heavy sender will need a quote.