Email APIs · side by side
Customer.io vs SendGrid
Compare Customer.io, SendGrid 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
SendGrid
100K
Customer.io
Custom / not listed
Custom / unlisted usage pricing · 25K profiles
SendGrid
$90 / mo
Pro · 100K emails
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 | SendGrid |
|---|---|---|
| Provider | Customer.io | Twilio |
| Billing unit | profiles | emails |
| Plan at selected usage | Custom / unlisted usage pricing | Pro |
| Monthly estimate | Custom / not listed | $90/mo |
| Workload | 25K profiles | 100K emails |
| Free access | Trial | 100 emails/day (trial) |
| Published plans | Essentials, Premium, Enterprise | Free Trial, Essentials, Pro, Premier |
| Prices checked | 2026-10-08 | 2026-10-08 |
Provider
- Customer.io
- Customer.io
- SendGrid
- Twilio
Billing unit
- Customer.io
- profiles
- SendGrid
- emails
Plan at selected usage
- Customer.io
- Custom / unlisted usage pricing
- SendGrid
- Pro
Monthly estimate
- Customer.io
- Custom / not listed
- SendGrid
- $90/mo
Workload
- Customer.io
- 25K profiles
- SendGrid
- 100K emails
Free access
- Customer.io
- Trial
- SendGrid
- 100 emails/day (trial)
Published plans
- Customer.io
- Essentials, Premium, Enterprise
- SendGrid
- Free Trial, Essentials, Pro, Premier
Prices checked
- Customer.io
- 2026-10-08
- SendGrid
- 2026-10-08
Email APIs monthly cost
Customer.io: Not pricedSendGrid: $90
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 | SendGrid |
|---|---|---|
| Single sign-on | Not listed | |
| SMTP and API | Not listed | |
| Comprehensive Client Libraries | Not listed | |
| Setup Guide | Not listed | |
| Interactive API Docs | Not listed | |
| Knowledge Center | Not listed | |
| Purpose-Built Mail Transfer Agent | Not listed | |
| Domain Authentication (SPF/DKIM) | Not listed | |
| Dedicated IP Addresses | Not listed | 1 included* |
| Dedicated IP Pooling | Not listed | |
| Automated, dedicated IP warm up | Not listed | |
| Email Address Validation API | Not listed | 2,500 free validations included |
| Reputation & Delivery Visibility | Not listed | |
| Suppression Management | Not listed | |
| Globally Distributed Architecture | Not listed | |
| Link Branding | Not listed | |
| Reverse DNS | Not listed | |
| Universal Links | Not listed | |
| IP Access Management | Not listed | |
| Two-Factor Authentication | Not listed | |
| TLS Encryption | Not listed | |
| SOC 2 Type II Certification | Not listed | |
| GDPR Compliance | Not listed | |
| Data Residency (EU) | Not listed | |
| Event Webhook Security | Not listed | |
| Event Webhook | Not listed | 5 included |
| Deliverability Insights | Not listed | |
| Real-Time Analytics | Not listed | |
| Advanced Statistics | Not listed | |
| Inbound Parse Webhook | Not listed | |
| Bounce and Block Classifications | Not listed | |
| Engagement Tracking | Not listed | |
| ISP Feedback Loop Data | Not listed | |
| Subuser Comparison Statistics | Not listed | |
| Searchable Email Activity | Not listed | 7 days of history |
| Additional Email Activity History | Not listed | Available for purchase |
| Sender Engagement Quality Score | Not listed | |
| Email Logs | Not listed | |
| Access to Expert Services | Not listed | Available for purchase |
| Access to Personalized Support | Not listed | Available for purchase |
| Expert Email Program Management | Not listed | |
| Dynamic Templates | Not listed | |
| Email Content Testing | Not listed | 60 credits/mo (more for purchase) |
| Teammate Permissions | Not listed | 1,000 teammates |
| API Key Permissions | Not listed | |
| Subuser Management | Not listed |
Single sign-on
- Customer.io
- Not listed
- SendGrid
SMTP and API
- Customer.io
- Not listed
- SendGrid
Comprehensive Client Libraries
- Customer.io
- Not listed
- SendGrid
Setup Guide
- Customer.io
- Not listed
- SendGrid
Interactive API Docs
- Customer.io
- Not listed
- SendGrid
Knowledge Center
- Customer.io
- Not listed
- SendGrid
Purpose-Built Mail Transfer Agent
- Customer.io
- Not listed
- SendGrid
Domain Authentication (SPF/DKIM)
- Customer.io
- Not listed
- SendGrid
Dedicated IP Addresses
- Customer.io
- Not listed
- SendGrid
- 1 included*
Dedicated IP Pooling
- Customer.io
- Not listed
- SendGrid
Automated, dedicated IP warm up
- Customer.io
- Not listed
- SendGrid
Email Address Validation API
- Customer.io
- Not listed
- SendGrid
- 2,500 free validations included
Reputation & Delivery Visibility
- Customer.io
- Not listed
- SendGrid
Suppression Management
- Customer.io
- Not listed
- SendGrid
Globally Distributed Architecture
- Customer.io
- Not listed
- SendGrid
Link Branding
- Customer.io
- Not listed
- SendGrid
Reverse DNS
- Customer.io
- Not listed
- SendGrid
Universal Links
- Customer.io
- Not listed
- SendGrid
IP Access Management
- Customer.io
- Not listed
- SendGrid
Two-Factor Authentication
- Customer.io
- Not listed
- SendGrid
TLS Encryption
- Customer.io
- Not listed
- SendGrid
SOC 2 Type II Certification
- Customer.io
- Not listed
- SendGrid
GDPR Compliance
- Customer.io
- Not listed
- SendGrid
Data Residency (EU)
- Customer.io
- Not listed
- SendGrid
Event Webhook Security
- Customer.io
- Not listed
- SendGrid
Event Webhook
- Customer.io
- Not listed
- SendGrid
- 5 included
Deliverability Insights
- Customer.io
- Not listed
- SendGrid
Real-Time Analytics
- Customer.io
- Not listed
- SendGrid
Advanced Statistics
- Customer.io
- Not listed
- SendGrid
Inbound Parse Webhook
- Customer.io
- Not listed
- SendGrid
Bounce and Block Classifications
- Customer.io
- Not listed
- SendGrid
Engagement Tracking
- Customer.io
- Not listed
- SendGrid
ISP Feedback Loop Data
- Customer.io
- Not listed
- SendGrid
Subuser Comparison Statistics
- Customer.io
- Not listed
- SendGrid
Searchable Email Activity
- Customer.io
- Not listed
- SendGrid
- 7 days of history
Additional Email Activity History
- Customer.io
- Not listed
- SendGrid
- Available for purchase
Sender Engagement Quality Score
- Customer.io
- Not listed
- SendGrid
Email Logs
- Customer.io
- Not listed
- SendGrid
Access to Expert Services
- Customer.io
- Not listed
- SendGrid
- Available for purchase
Access to Personalized Support
- Customer.io
- Not listed
- SendGrid
- Available for purchase
Expert Email Program Management
- Customer.io
- Not listed
- SendGrid
Dynamic Templates
- Customer.io
- Not listed
- SendGrid
Email Content Testing
- Customer.io
- Not listed
- SendGrid
- 60 credits/mo (more for purchase)
Teammate Permissions
- Customer.io
- Not listed
- SendGrid
- 1,000 teammates
API Key Permissions
- Customer.io
- Not listed
- SendGrid
Subuser Management
- Customer.io
- Not listed
- SendGrid
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Which email providers fit your needs?
Customer.io features & plan notes
- Behavioral messaging
- Lifecycle workflows
- Event triggers
SendGrid features & plan notes
- Marketing + transactional
- Mature deliverability
- Analytics & deliverability optimization
- Dedicated IPs included
- Subuser management
- Single sign-on (SSO)
- Additional teammates: 1,000
- Event webhook: 5
- Email validation: 2,500
- Dynamic templates: Editor and testing
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