Marketing · head to head
Customer.io vs Mailgun
Customer.io
Marketing
Data-driven messaging for teams getting started, scaling and beyond
- From
- $15/month
- Rated
- -
The short version
- Only Mailgun has a free tier, so it costs nothing to try first.
- Each has a real cost: Customer.io essentials plan caps at 5,000 profiles (people and objects) and 1,000,000 monthly emails, with overages billed at $0.12 per 1,000 emails beyond that; Mailgun free tier limited to 100 emails per day, restricting high-volume use cases
- Prices and features above were last checked on 29 August 2026.
Where they differ
Only the attributes on which Customer.io and Mailgun actually diverge.
| Attribute | Customer.io | Mailgun |
|---|---|---|
| Starting price | $15/month | Free |
| Free tier | No | Yes |
Identical on both: pricing model (subscription), platforms (Web), user rating (Not yet rated), category (Marketing).
What people use each for
The jobs each tool is most often brought in to do.
Customer.io
- Orchestrating multi-channel customer journeys from signup to retentionnot Mailgun
- Personalizing email and SMS campaigns using customer profilesnot Mailgun
- Triggering automated messages based on user behaviornot Mailgun
- Coordinating cross-team messaging without rebuilding campaignsnot Mailgun
Mailgun
- Transactional email delivery and SMTP relaynot Customer.io
- Email marketing at scale for developers and enterprisesnot Customer.io
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Customer.io
- Essentials plan caps at 5,000 profiles (people and objects) and 1,000,000 monthly emails, with overages billed at $0.12 per 1,000 emails beyond that
- Standard and Premium tiers show custom pricing only, and Enterprise is negotiated rate, so three of the four published tiers require a sales conversation
- Monthly plans accept credit card only; annual billing via invoice (ACH/wire) requires the annual commitment
Mailgun
- Free tier limited to 100 emails per day, restricting high-volume use cases
- Log retention minimal on lower tiers (1 day on Free and Basic plans)
- Add-on pricing for email validations and extra emails can accumulate quickly for high-traffic users
Pricing, plan by plan
Customer.io
$15/month- Essentials$15/month
- Base profiles starting at 5,000
- Email sends: 1 million monthly
- Community and email support
- Standard$null/month
- Mid-tier scaling across channels
- Higher profile and email allowances
- Email and priority support
- Premium$null/month
- Advanced custom workflows
- Dedicated support
- Enterprise$null/month
- Custom pricing for dedicated infrastructure
- HIPAA compliance
- Dedicated hardware
Mailgun
Free- FreeFree
- 100 emails per day
- Basic APIs
- SMTP relay
- Basic$15/monthly
- 10,000 emails per month
- No daily limits
- Monthly overage options
- Foundation$35/monthly
- 50,000 emails per month
- 1,000 custom domains
- Email template builder
- Scale$90/monthly
- 100,000 emails per month
- SAML SSO
- 5,000 email validations
Which should you pick?
Choose Customer.io if
Nothing in the data separates Customer.io from Mailgun on the points above - pick on price and on how each one feels to use.
Questions people ask
- Is Customer.io or Mailgun better?
- Neither clearly leads. Customer.io starts at $15/month and Mailgun at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Customer.io or Mailgun?
- Mailgun has a free tier; the other does not. Paid plans start at $15/month for Customer.io and Free for Mailgun.
- Does Customer.io or Mailgun run on more platforms?
- Both run on Web, so platform support will not decide this one for you.
- Can I use Mailgun for free?
- Yes. Mailgun has a free tier, so you can try it without paying. Customer.io starts at $15/month.
- What is Customer.io best used for?
- Customer.io is most often used for orchestrating multi-channel customer journeys from signup to retention, personalizing email and sms campaigns using customer profiles, triggering automated messages based on user behavior, coordinating cross-team messaging without rebuilding campaigns. Of those, orchestrating multi-channel customer journeys from signup to retention and personalizing email and sms campaigns using customer profiles are not what Mailgun is typically brought in for.
Answered from the vendors’ own pages
Customer.io: How much does Customer.io Essentials cost?
Customer.io Essentials starts at $15/month and includes 5,000 base profiles with 1 million monthly email sends, community and email support, and data-driven messaging tools. Customers can choose monthly or annual billing.
SourceMailgun: What happens when I exceed my monthly email quota?
Mailgun allows monthly overage options on paid plans. Extra emails are charged from $1.30 to $1.10 per 1,000 emails depending on plan tier. Enterprise customers negotiate custom rates.
SourceCustomer.io: What are Customer.io's usage-based add-on costs?
Beyond plan limits, Customer.io charges $0.009 per additional profile, $0.12 per 1,000 additional emails, and $10 per 100K AI credits. Messages exceeding plan limits are charged at nominal rates. Billing occurs on the subscription anniversary.
SourceMailgun: Can I upgrade from Free to a paid plan and when does billing begin?
Yes, you can upgrade to paid plans anytime. The first month is free on Foundation ($35/month) and Scale ($90/month) plans, with billing starting on month two.
SourceCustomer.io: Does Customer.io offer a startup discount?
Yes, early-stage companies that have raised under $10 million qualify for a full year free through Customer.io's Startup Program with annual billing.
SourceMailgun: What currencies and billing periods does Mailgun support?
Mailgun supports monthly billing in USD, EUR, and GBP. Charges are prorated for mid-month signups. Annual billing options are not explicitly listed on the pricing page.
SourceRelated pages
More on Customer.io
Other head to heads
- Customer.io vs Netcore Cloud
- Customer.io vs Bloomreach
- Customer.io vs CleverTap
- Customer.io vs Wrike
- Customer.io vs Buffer
- Customer.io vs Hootsuite
- Customer.io vs Moz
- Customer.io vs MoEngage
- Customer.io vs Iterable
- Customer.io vs Insider
- Customer.io vs WebEngage
- Customer.io vs Zoho Marketing Automation
- Customer.io vs Adverity
- Customer.io vs CallRail
- Customer.io vs Convert
- Customer.io vs Datorama
- Customer.io vs Postmark
- Customer.io vs Northbeam
- Customer.io vs Ahrefs
- Customer.io vs Attribution
- Customer.io vs Instapage
- Customer.io vs Woopra
- Customer.io vs Wunderkind
- Customer.io vs Typeform
- Customer.io vs Optimizely
- Mailgun vs Netcore Cloud
- Mailgun vs Bloomreach
- Mailgun vs CleverTap
- Mailgun vs Wrike
- Mailgun vs Buffer
- Mailgun vs Hootsuite
- Mailgun vs Moz
- Mailgun vs MoEngage
- Mailgun vs Iterable
- Mailgun vs Insider
- Mailgun vs WebEngage
- Mailgun vs Zoho Marketing Automation
- Mailgun vs Adverity
- Mailgun vs CallRail
- Mailgun vs Convert
- Mailgun vs Datorama
- Mailgun vs Postmark
- Mailgun vs Northbeam
- Mailgun vs Ahrefs
- Mailgun vs Attribution
- Mailgun vs Instapage
- Mailgun vs Woopra
- Mailgun vs Wunderkind
- Mailgun vs Typeform
- Mailgun vs Optimizely