Customer.io
Turn customer data into personalized experiences that drive better business outcomes
About Customer.io
Customer.io is a customer engagement platform that sends behavior-triggered email, push, in-app, SMS, and WhatsApp messages from real-time product and customer data. Teams build cross-channel journeys in a visual workflow builder, segment audiences on events and custom objects, and can now hand campaign setup and analysis to a built-in AI Agent. It is aimed at product-led SaaS, mobile apps, and other data-heavy businesses running lifecycle marketing.
Pros & Cons
Pros
- Event-driven automation reacts to real-time product behavior, not just list membership or static attributes
- Push, in-app, SMS, WhatsApp, and email run from one workflow builder instead of separate tools
- Custom objects let you message on accounts, subscriptions, or other non-person entities, which suits B2B SaaS
- Unlimited user seats and unlimited API calls on every plan
- Strong developer surface: well-documented APIs, mobile SDKs, reverse ETL, and an MCP server for AI tools
- Startup Program gives qualifying companies (raised under $10M) 12 months free
Cons
- Billing counts every stored profile, active or not, so costs climb quickly as your database grows
- Big price jump from Essentials ($100/month) to Premium (from $1,000/month, annual contract only)
- Chat support, onboarding, and managed deliverability are not included on Essentials
- Getting full value needs engineering time to send clean event data and attributes
- Some users find the Liquid-based template language limiting for complex email logic
Key Features
Journeys visual workflow builder
Build event-triggered, cross-channel automations with branching, delays, A/B and multivariate tests, send-time optimization, and LLM actions inside the workflow.
Multichannel messaging
Send email (marketing and transactional), push, in-app, SMS, WhatsApp, LINE, and webhooks from one platform; push, in-app, and webhook sends are unlimited on every plan.
AI Agent
Describe a goal in plain language and the agent configures automations with triggers, content, timing, and logic, analyzes campaign performance, and can run scheduled Routines.
Audiences and custom objects
Segment on unlimited people attributes, nested data, and custom objects such as accounts or courses, with an AI-powered segment builder and ad audience sync.
Design Studio
Drag-and-drop and code editors with reusable components, saved templates with version control, AI translation, email content analysis, and inbox previews.
Data and integrations
Unlimited API calls, reverse ETL from your warehouse, connected forms, an MCP server, and CLI access so external AI tools can work with your Customer.io data.
Analytics and reporting
Campaign and workspace dashboards, conversion tracking, survey analysis, and data export to measure the business impact of each message.
Security and compliance
SSO, two-factor authentication, US and EU data centers, SOC 2 Type II, GDPR and CCPA support, with HIPAA compliance available on higher plans.
Pricing
- Starts at 5,000 profiles (people + objects), billed monthly
- 1 million emails per month
- Unlimited push, in-app messages, and webhooks
- AI Agent with core execution skills (3 custom skills, 1 weekly Routine)
- 2 object types and 2 workspaces
- Visual workflow builder
- Basic data integrations
- Email and community support
- Unlimited user seats
- Additional profiles $0.009 each; additional 1,000 emails $0.12
- Everything in Essentials
- Custom profile and email volume and pricing
- 10 object types and unlimited workspaces
- Elevated AI Agent limits, 10 custom skills, 5 daily Routines
- Premium data integrations, data warehouse destinations, data replay
- Custom role-based permissions and managed deliverability
- Premium chat and email support with 90-day onboarding
- HIPAA compliance (additional cost)
- Everything in Premium
- Best pricing on profile and email volume
- Custom AI Agent limits and execution skills
- Dedicated hardware
- Audit logging and data governance
- Priority technical support
- Dedicated Customer Success Manager (additional cost)
- Shared Slack channel (additional cost)
Best For
SaaS onboarding and activation
Trigger welcome and nudge sequences from product events so new users reach their first meaningful action faster.
Retention and churn prevention
Detect drops in engagement or cancellation signals and respond automatically with targeted email, push, or in-app messages.
Mobile app engagement
Use the mobile SDKs to run push and in-app campaigns tied to in-app behavior, alongside email and SMS.
Transactional and product messaging
Send API-triggered receipts, alerts, and notifications from the same platform as marketing campaigns, with shared templates and reporting.
Cross-sell and upsell
Personalize upgrade and expansion campaigns based on product usage, plan data, and account-level custom objects.
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