Email APIs · side by side
Customer.io vs Kit
Compare Customer.io, Kit by sending volume, delivery webhooks, inbound email, domain limits and retention.
Email APIs pricing calculator
These providers bill in different units. Each estimate uses its own workload; there is no same-volume price winner.
Customer.io
25K
Kit
10K
Customer.io
Custom / not listed
Custom / unlisted usage pricing · 25K profiles
Kit
Custom / not listed
Custom / unlisted usage pricing · 10K subscribers
Listed USD plan fees and tracked usage only. Unlisted compute, transfer, extras, taxes and contract terms are excluded. Custom or unsupported plan usage is not estimated.
Email APIs overview & pricing
| Email APIs | Customer.io | Kit |
|---|---|---|
| Provider | Customer.io | Kit |
| Billing unit | profiles | subscribers |
| Plan at selected usage | Custom / unlisted usage pricing | Custom / unlisted usage pricing |
| Monthly estimate | Custom / not listed | Custom / not listed |
| Workload | 25K profiles | 10K subscribers |
| Free access | Trial | Creator free plan |
| Published plans | Essentials, Premium, Enterprise | Free, Creator, Pro |
| Prices checked | 2026-10-08 | 2026-10-08 |
Provider
- Customer.io
- Customer.io
- Kit
- Kit
Billing unit
- Customer.io
- profiles
- Kit
- subscribers
Plan at selected usage
- Customer.io
- Custom / unlisted usage pricing
- Kit
- Custom / unlisted usage pricing
Monthly estimate
- Customer.io
- Custom / not listed
- Kit
- Custom / not listed
Workload
- Customer.io
- 25K profiles
- Kit
- 10K subscribers
Free access
- Customer.io
- Trial
- Kit
- Creator free plan
Published plans
- Customer.io
- Essentials, Premium, Enterprise
- Kit
- Free, Creator, Pro
Prices checked
- Customer.io
- 2026-10-08
- Kit
- 2026-10-08
Email APIs monthly cost
Customer.io: Not pricedKit: Not priced
Different workloads, separate estimates
Separate transactional delivery from campaigns, outreach and agent inboxes. Compare monthly sends and daily caps; contacts, seats and inboxes are not sending allowances. Budget separately for dedicated IPs, validation and attachments.
Email APIs feature comparison
| Email APIs | Customer.io | Kit |
|---|---|---|
| Sending methods | Not listed | Not listed |
| Inbound processing | Not listed | Not listed |
| Sending domains | Not listed | Not listed |
| Activity retention | Not listed | Not listed |
| Webhooks & events | Not listed | Not listed |
| Dedicated IP | Not listed | Not listed |
| Single sign-on | Not listed | Not listed |
| Support | Not listed | Not listed |
| AI Agent (beta): Session limits | Not listed | Not listed |
| AI Agent (beta): Persistent Memory | Not listed | Not listed |
| AI Agent (beta): Core Execution Skills | Not listed | Not listed |
| AI Agent (beta): Custom Execution Skills | Not listed | Not listed |
| AI Agent (beta): Routines: # of tasks | Not listed | Not listed |
| AI Agent (beta): Routines: frequency | Not listed | Not listed |
| Monthly email sends | Not listed | Not listed |
| Transactional emails | Not listed | Not listed |
| Monthly push and in-app | Not listed | Not listed |
| Mobile SDKs | Not listed | Not listed |
| Monthly SMS sends | Not listed | Not listed |
| WhatsApp (Native) | Not listed | Not listed |
| LINE | Not listed | Not listed |
| Webhook (send & receive) | Not listed | Not listed |
| Anonymous messages | Not listed | Not listed |
| LLM actions | Not listed | Not listed |
| Visual workflow builder | Not listed | Not listed |
| Cross-channel campaign automation | Not listed | Not listed |
| Send-time optimization | Not listed | Not listed |
| In-app message suggestions | Not listed | Not listed |
| API-triggered broadcasts | Not listed | Not listed |
| Scalable Personalization | Not listed | Not listed |
| Custom SMTP | Not listed | Not listed |
| Profiles (people + objects) | Not listed | Not listed |
| People attributes | Not listed | Not listed |
| Custom objects | Not listed | Not listed |
| Object types | Not listed | Not listed |
| Segments | Not listed | Not listed |
| AI-powered segment builder | Not listed | Not listed |
| Suggested segments | Not listed | Not listed |
| Nested data | Not listed | Not listed |
| Ad audience sync | Not listed | Not listed |
| Custom collections | Not listed | Not listed |
| Drag-and-drop visual editor | Not listed | Not listed |
| Code editor | Not listed | Not listed |
| AI-generated global styles | Not listed | Not listed |
| AI translator for messages | Not listed | Not listed |
| Email content analysis | Not listed | Not listed |
| Reusable components | Not listed | Not listed |
| Saved templates & version control | Not listed | Not listed |
| Inbox previews | Not listed | Not listed |
| Monthly API calls | Not listed | Not listed |
| Integrations | Not listed | Not listed |
| MCP server | Not listed | Not listed |
| Data index | Not listed | Not listed |
| Connected forms | Not listed | Not listed |
| Privacy management | Not listed | Not listed |
| Reverse ETL | Not listed | Not listed |
| Data warehouse destinations | Not listed | Not listed |
| Data replay | Not listed | Not listed |
| Dashboards | Not listed | Not listed |
| Campaign reporting | Not listed | Not listed |
| Workspace performance dashboard | Not listed | Not listed |
| Survey analysis | Not listed | Not listed |
| Data export | Not listed | Not listed |
| A/B & multivariate testing | Not listed | Not listed |
| Conversion tracking | Not listed | Not listed |
| Universal search | Not listed | Not listed |
| SSO & 2-factor authentication | Not listed | Not listed |
| US / EU data centers | Not listed | Not listed |
| SOC Tier II Compliance | Not listed | Not listed |
| Standard role-based permissions | Not listed | Not listed |
| Custom role-based permissions | Not listed | Not listed |
| Managed deliverability | Not listed | Not listed |
| HIPAA Compliance | Not listed | Not listed |
| Audit logging & data governance | Not listed | Not listed |
| Dedicated hardware | Not listed | Not listed |
| Documentation | Not listed | Not listed |
| Community support | Not listed | Not listed |
| Email support | Not listed | Not listed |
| Chat support | Not listed | Not listed |
| Onboarding support | Not listed | Not listed |
| Dedicated Customer Success Manager | Not listed | Not listed |
| Migration support | Not listed | Not listed |
| Dedicated Technical Implementation Specialist | Not listed | Not listed |
| Shared Slack channel | Not listed | Not listed |
| 2-hour first outreach response time | Not listed | Not listed |
| User seats | Not listed | Not listed |
| Workspaces | Not listed | Not listed |
| Additional people & object profiles | Not listed | Not listed |
| Subscribers | Not listed | Not listed |
| Create landing pages | Not listed | Not listed |
| Create email opt-in forms | Not listed | Not listed |
| Create a newsletter feed & website | Not listed | Not listed |
| Landing page and form templates | Not listed | Not listed |
| Customizable domain | Not listed | Not listed |
| Unlimited traffic | Not listed | Not listed |
| Deliver opt-in incentives | Not listed | Not listed |
| List growth reporting | Not listed | Not listed |
| Free Recommendations | Not listed | Not listed |
| Smart Recommendations | Not listed | Not listed |
| Facebook custom audiences | Not listed | Not listed |
| Newsletter referral system | Not listed | Not listed |
| Growth Concierge team | Not listed | Not listed |
| Subscriber tagging | Not listed | Not listed |
| Subscriber segmentation | Not listed | Not listed |
| Unsubscribe page builder | Not listed | Not listed |
| Users | Not listed | Not listed |
| Subscriber engagement scoring | Not listed | Not listed |
| Subscriber Signals | Not listed | Not listed |
| Engagement analytics | Not listed | Not listed |
| Send email broadcasts | Not listed | Not listed |
| Email template library | Not listed | Not listed |
| Image library | Not listed | Not listed |
| Create custom email templates | Not listed | Not listed |
| Conditional email content | Not listed | Not listed |
| Resend unopened campaigns | Not listed | Not listed |
| A/B split testing | Not listed | Not listed |
| Remove Kit branding | Not listed | Not listed |
| Email editor version history | Not listed | Not listed |
| Schedule in subscriber’s local time zone | Not listed | Not listed |
| Advanced A/B split testing | Not listed | Not listed |
| Collaborative editing | Not listed | Not listed |
| Edit links in sent broadcasts | Not listed | Not listed |
| Deliverability reporting | Not listed | Not listed |
| Insights dashboard | Not listed | Not listed |
| Custom tracking domain | Not listed | Not listed |
| Content snippets | Not listed | Not listed |
| Visual automation template library | Not listed | Not listed |
| Visual automation builder | Not listed | Not listed |
| API documentation | Not listed | Not listed |
| Automated email sequences | Not listed | Not listed |
| RSS Campaigns | Not listed | Not listed |
| 100+ direct apps | Not listed | Not listed |
| Kit MCP | Not listed | Not listed |
| Sell digital products | Not listed | Not listed |
| Run paid newsletters | Not listed | Not listed |
| Sell recurring subscriptions | Not listed | Not listed |
| Set up virtual tip jars | Not listed | Not listed |
| Low transaction fees | Not listed | Not listed |
| Paid Recommendations | Not listed | Not listed |
| Paid Recommendations fees | Not listed | Not listed |
| Newsletter sponsorships | Not listed | Not listed |
| Abandon checkout | Not listed | Not listed |
| Kit University | Not listed | Not listed |
| Product support | Not listed | Not listed |
| Free migration from another platform | Not listed | Not listed |
Sending methods
- Customer.io
- Not listed
- Kit
- Not listed
Inbound processing
- Customer.io
- Not listed
- Kit
- Not listed
Sending domains
- Customer.io
- Not listed
- Kit
- Not listed
Activity retention
- Customer.io
- Not listed
- Kit
- Not listed
Webhooks & events
- Customer.io
- Not listed
- Kit
- Not listed
Dedicated IP
- Customer.io
- Not listed
- Kit
- Not listed
Single sign-on
- Customer.io
- Not listed
- Kit
- Not listed
Support
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Session limits
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Persistent Memory
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Core Execution Skills
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Custom Execution Skills
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Routines: # of tasks
- Customer.io
- Not listed
- Kit
- Not listed
AI Agent (beta): Routines: frequency
- Customer.io
- Not listed
- Kit
- Not listed
Monthly email sends
- Customer.io
- Not listed
- Kit
- Not listed
Transactional emails
- Customer.io
- Not listed
- Kit
- Not listed
Monthly push and in-app
- Customer.io
- Not listed
- Kit
- Not listed
Mobile SDKs
- Customer.io
- Not listed
- Kit
- Not listed
Monthly SMS sends
- Customer.io
- Not listed
- Kit
- Not listed
WhatsApp (Native)
- Customer.io
- Not listed
- Kit
- Not listed
LINE
- Customer.io
- Not listed
- Kit
- Not listed
Webhook (send & receive)
- Customer.io
- Not listed
- Kit
- Not listed
Anonymous messages
- Customer.io
- Not listed
- Kit
- Not listed
LLM actions
- Customer.io
- Not listed
- Kit
- Not listed
Visual workflow builder
- Customer.io
- Not listed
- Kit
- Not listed
Cross-channel campaign automation
- Customer.io
- Not listed
- Kit
- Not listed
Send-time optimization
- Customer.io
- Not listed
- Kit
- Not listed
In-app message suggestions
- Customer.io
- Not listed
- Kit
- Not listed
API-triggered broadcasts
- Customer.io
- Not listed
- Kit
- Not listed
Scalable Personalization
- Customer.io
- Not listed
- Kit
- Not listed
Custom SMTP
- Customer.io
- Not listed
- Kit
- Not listed
Profiles (people + objects)
- Customer.io
- Not listed
- Kit
- Not listed
People attributes
- Customer.io
- Not listed
- Kit
- Not listed
Custom objects
- Customer.io
- Not listed
- Kit
- Not listed
Object types
- Customer.io
- Not listed
- Kit
- Not listed
Segments
- Customer.io
- Not listed
- Kit
- Not listed
AI-powered segment builder
- Customer.io
- Not listed
- Kit
- Not listed
Suggested segments
- Customer.io
- Not listed
- Kit
- Not listed
Nested data
- Customer.io
- Not listed
- Kit
- Not listed
Ad audience sync
- Customer.io
- Not listed
- Kit
- Not listed
Custom collections
- Customer.io
- Not listed
- Kit
- Not listed
Drag-and-drop visual editor
- Customer.io
- Not listed
- Kit
- Not listed
Code editor
- Customer.io
- Not listed
- Kit
- Not listed
AI-generated global styles
- Customer.io
- Not listed
- Kit
- Not listed
AI translator for messages
- Customer.io
- Not listed
- Kit
- Not listed
Email content analysis
- Customer.io
- Not listed
- Kit
- Not listed
Reusable components
- Customer.io
- Not listed
- Kit
- Not listed
Saved templates & version control
- Customer.io
- Not listed
- Kit
- Not listed
Inbox previews
- Customer.io
- Not listed
- Kit
- Not listed
Monthly API calls
- Customer.io
- Not listed
- Kit
- Not listed
Integrations
- Customer.io
- Not listed
- Kit
- Not listed
MCP server
- Customer.io
- Not listed
- Kit
- Not listed
Data index
- Customer.io
- Not listed
- Kit
- Not listed
Connected forms
- Customer.io
- Not listed
- Kit
- Not listed
Privacy management
- Customer.io
- Not listed
- Kit
- Not listed
Reverse ETL
- Customer.io
- Not listed
- Kit
- Not listed
Data warehouse destinations
- Customer.io
- Not listed
- Kit
- Not listed
Data replay
- Customer.io
- Not listed
- Kit
- Not listed
Dashboards
- Customer.io
- Not listed
- Kit
- Not listed
Campaign reporting
- Customer.io
- Not listed
- Kit
- Not listed
Workspace performance dashboard
- Customer.io
- Not listed
- Kit
- Not listed
Survey analysis
- Customer.io
- Not listed
- Kit
- Not listed
Data export
- Customer.io
- Not listed
- Kit
- Not listed
A/B & multivariate testing
- Customer.io
- Not listed
- Kit
- Not listed
Conversion tracking
- Customer.io
- Not listed
- Kit
- Not listed
Universal search
- Customer.io
- Not listed
- Kit
- Not listed
SSO & 2-factor authentication
- Customer.io
- Not listed
- Kit
- Not listed
US / EU data centers
- Customer.io
- Not listed
- Kit
- Not listed
SOC Tier II Compliance
- Customer.io
- Not listed
- Kit
- Not listed
Standard role-based permissions
- Customer.io
- Not listed
- Kit
- Not listed
Custom role-based permissions
- Customer.io
- Not listed
- Kit
- Not listed
Managed deliverability
- Customer.io
- Not listed
- Kit
- Not listed
HIPAA Compliance
- Customer.io
- Not listed
- Kit
- Not listed
Audit logging & data governance
- Customer.io
- Not listed
- Kit
- Not listed
Dedicated hardware
- Customer.io
- Not listed
- Kit
- Not listed
Documentation
- Customer.io
- Not listed
- Kit
- Not listed
Community support
- Customer.io
- Not listed
- Kit
- Not listed
Email support
- Customer.io
- Not listed
- Kit
- Not listed
Chat support
- Customer.io
- Not listed
- Kit
- Not listed
Onboarding support
- Customer.io
- Not listed
- Kit
- Not listed
Dedicated Customer Success Manager
- Customer.io
- Not listed
- Kit
- Not listed
Migration support
- Customer.io
- Not listed
- Kit
- Not listed
Dedicated Technical Implementation Specialist
- Customer.io
- Not listed
- Kit
- Not listed
Shared Slack channel
- Customer.io
- Not listed
- Kit
- Not listed
2-hour first outreach response time
- Customer.io
- Not listed
- Kit
- Not listed
User seats
- Customer.io
- Not listed
- Kit
- Not listed
Workspaces
- Customer.io
- Not listed
- Kit
- Not listed
Additional people & object profiles
- Customer.io
- Not listed
- Kit
- Not listed
Subscribers
- Customer.io
- Not listed
- Kit
- Not listed
Create landing pages
- Customer.io
- Not listed
- Kit
- Not listed
Create email opt-in forms
- Customer.io
- Not listed
- Kit
- Not listed
Create a newsletter feed & website
- Customer.io
- Not listed
- Kit
- Not listed
Landing page and form templates
- Customer.io
- Not listed
- Kit
- Not listed
Customizable domain
- Customer.io
- Not listed
- Kit
- Not listed
Unlimited traffic
- Customer.io
- Not listed
- Kit
- Not listed
Deliver opt-in incentives
- Customer.io
- Not listed
- Kit
- Not listed
List growth reporting
- Customer.io
- Not listed
- Kit
- Not listed
Free Recommendations
- Customer.io
- Not listed
- Kit
- Not listed
Smart Recommendations
- Customer.io
- Not listed
- Kit
- Not listed
Facebook custom audiences
- Customer.io
- Not listed
- Kit
- Not listed
Newsletter referral system
- Customer.io
- Not listed
- Kit
- Not listed
Growth Concierge team
- Customer.io
- Not listed
- Kit
- Not listed
Subscriber tagging
- Customer.io
- Not listed
- Kit
- Not listed
Subscriber segmentation
- Customer.io
- Not listed
- Kit
- Not listed
Unsubscribe page builder
- Customer.io
- Not listed
- Kit
- Not listed
Users
- Customer.io
- Not listed
- Kit
- Not listed
Subscriber engagement scoring
- Customer.io
- Not listed
- Kit
- Not listed
Subscriber Signals
- Customer.io
- Not listed
- Kit
- Not listed
Engagement analytics
- Customer.io
- Not listed
- Kit
- Not listed
Send email broadcasts
- Customer.io
- Not listed
- Kit
- Not listed
Email template library
- Customer.io
- Not listed
- Kit
- Not listed
Image library
- Customer.io
- Not listed
- Kit
- Not listed
Create custom email templates
- Customer.io
- Not listed
- Kit
- Not listed
Conditional email content
- Customer.io
- Not listed
- Kit
- Not listed
Resend unopened campaigns
- Customer.io
- Not listed
- Kit
- Not listed
A/B split testing
- Customer.io
- Not listed
- Kit
- Not listed
Remove Kit branding
- Customer.io
- Not listed
- Kit
- Not listed
Email editor version history
- Customer.io
- Not listed
- Kit
- Not listed
Schedule in subscriber’s local time zone
- Customer.io
- Not listed
- Kit
- Not listed
Advanced A/B split testing
- Customer.io
- Not listed
- Kit
- Not listed
Collaborative editing
- Customer.io
- Not listed
- Kit
- Not listed
Edit links in sent broadcasts
- Customer.io
- Not listed
- Kit
- Not listed
Deliverability reporting
- Customer.io
- Not listed
- Kit
- Not listed
Insights dashboard
- Customer.io
- Not listed
- Kit
- Not listed
Custom tracking domain
- Customer.io
- Not listed
- Kit
- Not listed
Content snippets
- Customer.io
- Not listed
- Kit
- Not listed
Visual automation template library
- Customer.io
- Not listed
- Kit
- Not listed
Visual automation builder
- Customer.io
- Not listed
- Kit
- Not listed
API documentation
- Customer.io
- Not listed
- Kit
- Not listed
Automated email sequences
- Customer.io
- Not listed
- Kit
- Not listed
RSS Campaigns
- Customer.io
- Not listed
- Kit
- Not listed
100+ direct apps
- Customer.io
- Not listed
- Kit
- Not listed
Kit MCP
- Customer.io
- Not listed
- Kit
- Not listed
Sell digital products
- Customer.io
- Not listed
- Kit
- Not listed
Run paid newsletters
- Customer.io
- Not listed
- Kit
- Not listed
Sell recurring subscriptions
- Customer.io
- Not listed
- Kit
- Not listed
Set up virtual tip jars
- Customer.io
- Not listed
- Kit
- Not listed
Low transaction fees
- Customer.io
- Not listed
- Kit
- Not listed
Paid Recommendations
- Customer.io
- Not listed
- Kit
- Not listed
Paid Recommendations fees
- Customer.io
- Not listed
- Kit
- Not listed
Newsletter sponsorships
- Customer.io
- Not listed
- Kit
- Not listed
Abandon checkout
- Customer.io
- Not listed
- Kit
- Not listed
Kit University
- Customer.io
- Not listed
- Kit
- Not listed
Product support
- Customer.io
- Not listed
- Kit
- Not listed
Free migration from another platform
- Customer.io
- Not listed
- Kit
- Not listed
Showing 15 of 145
Which email providers fit your needs?
Customer.io features & plan notes
- Behavioral messaging
- Lifecycle workflows
- Event triggers
How to compare email providers
Separate transactional delivery from campaigns, outreach and agent inboxes. Compare monthly sends and daily caps; contacts, seats and inboxes are not sending allowances. Budget separately for dedicated IPs, validation and attachments.
Browse Email APIs pricing