Customer.io vs Mailgun
Side-by-side plans, pricing, and feature gates for Customer.io and Mailgun, verified . Customer.io is primarily marketing automation; Mailgun is primarily transactional email.
Plans side by side
Every published plan from each vendor, with the headline monthly anchor price. Some prices scale with subscriber count or seats; full detail lives on each tool's page.
Customer.io
- Essentials
Entry tier with the visual workflow builder
$100/mo - Premium
Custom volume, HIPAA available, daily routines
$1,000/mo - Enterprise
Best volume pricing with dedicated infrastructure
Custom
Mailgun
- Free
Hobby tier capped at 100 emails per day
Free - Basic
Entry paid tier with 10,000 emails/month included
$15/mo - Foundation
50,000 emails/month with template builder and full inbound routing
$35/mo - Scale
100,000 emails/month with SAML SSO, dedicated IP, and live support
$90/mo - Enterprise
Custom contracting for high-volume senders
Custom
Limits at the entry paid tier
Compares Essentials (Customer.io) against Basic (Mailgun). Both are the lowest-priced non-free, non-custom plan on each side.
| Limit | Customer.io | Mailgun |
|---|---|---|
| Contacts | 5,000 profiles (people plus objects) | · |
| Emails / month | 1,000,000 | 10,000 |
| Team seats | 1 | · |
When Customer.io wins
- B2C and B2B teams with custom objects in their data model (accounts, subscriptions, devices) who need messaging tied to those entities
- Product-led businesses sending behavior-triggered lifecycle messaging across email, SMS, and push
- Teams needing HIPAA compliance for healthcare or digital-health workflows
Where Customer.io is the wrong fit
- Solo creators and newsletter operators (Kit or beehiiv are the right shape)
- Small businesses that need a $0/month or $20/month entry point (MailerLite or Mailchimp Free fit better)
- Teams that want a one-click WYSIWYG email tool with no data modeling required
When Mailgun wins
- Developers integrating receipts, notifications, and password-reset emails
- Teams already on a marketing ESP that need a separate transactional channel
- High-volume B2B applications with strict deliverability requirements
Where Mailgun is the wrong fit
- Marketing teams seeking campaign tooling (use Mailchimp or Kit)
- Creators sending newsletters (use Kit or beehiiv)
- Free-tier hobbyists with low total volume but spiky daily-cap-bumping use cases
Common questions
- Is Customer.io cheaper than Mailgun?
- At the entry tier, Mailgun starts at Free versus Customer.io at $100/mo. Mailgun is cheaper at the entry. Pricing scales differently above that, so check the full plan grid.
- Does Customer.io or Mailgun have a free plan?
- Only Mailgun has a permanent free plan. Customer.io only offers a free trial.
- Are Customer.io and Mailgun in the same category?
- No. Customer.io is primarily a marketing automation tool; Mailgun is primarily a transactional email tool. They overlap on use case but sit in different primary categories, so the comparison is between adjacent tools rather than direct competitors.
- Which has more plans, Customer.io or Mailgun?
- Mailgun ships 5 plans; Customer.io ships 3. Mailgun's longer ladder gives more granular upgrade steps, which can mean smoother price escalation as your team scales.
- Where can I see alternatives to Customer.io or Mailgun?
- Each tool has a dedicated alternatives page on TierGauge with ranked options and verified pricing: /alternatives/customer-io for Customer.io and /alternatives/mailgun for Mailgun. Alternatives are derived from each tool's editor-flagged competitors plus same-category tools we track.
Customer.io: https://customer.io/pricing/ · Mailgun: https://www.mailgun.com/pricing/
Last verified . Pricing changes between refreshes; confirm at the vendor before purchasing.