Email APIs · side by side
Customer.io vs Mandrill
Compare Customer.io, Mandrill 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
Mandrill
Customer.io
Custom / not listed
Custom / unlisted usage pricing · 25K profiles
Mandrill
$0 / mo
Try for free · 0 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 | Mandrill |
|---|---|---|
| Provider | Customer.io | Mailchimp |
| Billing unit | profiles | emails |
| Plan at selected usage | Custom / unlisted usage pricing | Try for free |
| Monthly estimate | Custom / not listed | $0/mo |
| Workload | 25K profiles | 0 emails |
| Free access | Trial | Up to 500 free demo/test email sends to a verified domain for new users. |
| Published plans | Essentials, Premium, Enterprise | Try for free, Transactional Email |
| Prices checked | 2026-10-08 | 2026-10-08 |
- Customer.io
- Customer.io
- Mandrill
- Mailchimp
- Customer.io
- profiles
- Mandrill
- emails
- Customer.io
- Custom / unlisted usage pricing
- Mandrill
- Try for free
- Customer.io
- Custom / not listed
- Mandrill
- $0/mo
- Customer.io
- 25K profiles
- Mandrill
- 0 emails
- Customer.io
- Trial
- Mandrill
- Up to 500 free demo/test email sends to a verified domain for new users.
- Customer.io
- Essentials, Premium, Enterprise
- Mandrill
- Try for free, Transactional Email
- Customer.io
- 2026-10-08
- Mandrill
- 2026-10-08
Email APIs monthly cost
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.
Which email providers fit your needs?
Customer.io features & plan notes
- Behavioral messaging
- Lifecycle workflows
- Event triggers
Mandrill features & plan notes
- Send transactional emails via REST API or SMTP credentials
- Sold in blocks of 25,000 emails with volume discounts from $20 down to $10 per block
- Inbound email processing and real-time event webhooks
- Custom domain whitelabeling, dedicated IPs, and rules engine
- Up to 500 free email sends to your verified domain
- Streamlined template editing with drag and drop builder
- Developer documentation, guides, and SDK repositories
- Connect AI coding assistant directly through first-party MCP server
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