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Marketing · head to head

Mailgun vs SurveyCTO

Mailgun logo

Mailgun

Marketing

Email delivery built for developers

From
Free
Free plan
Yes
Full reviewWebsite
SurveyCTO logo

SurveyCTO

Surveys

Offline field survey platform priced by submissions rather than seats, built for research data quality

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Mailgun free tier limited to 100 emails per day, restricting high-volume use cases; SurveyCTO pricing is by submission volume, forms and storage rather than by users, so a small team running continuous high-volume collection can pay more than a 200-person survey team that runs for six weeks
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Mailgun and SurveyCTO actually diverge.

Attributes where Mailgun and SurveyCTO differ
AttributeMailgunSurveyCTO
Pricing modelsubscriptionPer month by submission volume
PlatformsWebWeb, Android, iOS
CategoryMarketingSurveys

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Mailgun

Nothing recorded that SurveyCTO does not also cover.

Only in SurveyCTO

  • Offline collection
  • XLSForm authoring
  • Automated quality checks
  • Audio auditing
  • Case management
  • Random assignment
  • Server region selection

What people use each for

The jobs each tool is most often brought in to do.

Mailgun

  • Transactional email delivery and SMTP relaynot SurveyCTO
  • Email marketing at scale for developers and enterprisesnot SurveyCTO

SurveyCTO

  • A household survey with 200 enumerators across a country where paying per seat would cost more than the fieldworknot Mailgun
  • An impact evaluation that needs audio auditing and timing metadata to prove interviews were conducted as reportednot Mailgun
  • A panel study revisiting the same households annually and needing offline case assignment to find them againnot Mailgun
  • A statistics unit that must keep data inside a specific region and produce a SOC 2 report for its fundernot Mailgun

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

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

SurveyCTO

  • Pricing is by submission volume, forms and storage rather than by users, so a small team running continuous high-volume collection can pay more than a 200-person survey team that runs for six weeks
  • Forms are authored in XLSForm spreadsheet syntax, which is precise and versionable but has a real learning curve, and organisations without someone comfortable in it stall at form design
  • Overage is charged at 100 US dollars per 1,000 extra submissions, which is easy to trigger on the Basic tier at 5,000 a month and produces surprise invoices during an active field round
  • Server region selection only appears on the Pro tier and a custom GDPR data processing agreement only on Advanced, so European data protection requirements push the price to at least 315 and often 630 dollars a month regardless of volume
  • It is built for structured research fieldwork, not for business process forms, so it has no dispatch, no invoicing and no formatted document output, and a field service business would be buying the wrong tool

Pricing, plan by plan

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

SurveyCTO

Free
  • CommunityFree
    • Permanent free subscription for testing and training
    • 10 forms
    • 200 monthly submissions
  • Basic$225/month
    • Billed annually, 250 USD month to month
    • 100 forms
    • 10 GB storage
  • Pro$315/month
    • Billed annually, 350 USD month to month
    • 500 forms
    • 25 GB storage
  • Advanced$630/month
    • Billed annually, 700 USD month to month
    • Unlimited forms, storage and submissions
    • Advanced offline case management

Which should you pick?

Choose Mailgun if

  • You want to start without paying.
Mailgun review

Choose SurveyCTO if

  • You need offline collection.
  • You want to start without paying.
  • You work on Web, Android, iOS.
  • You also want xlsform authoring.
SurveyCTO review

Questions people ask

Is Mailgun or SurveyCTO better?
Neither clearly leads. Mailgun starts at Free and SurveyCTO at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Mailgun or SurveyCTO?
Mailgun starts at Free and SurveyCTO at Free.
Does Mailgun or SurveyCTO run on more platforms?
Mailgun runs on Web. SurveyCTO runs on Web, Android, iOS.
Can I use Mailgun for free?
Both have a free tier, so you can try either at no cost before committing.
What is Mailgun best used for?
Mailgun is most often used for transactional email delivery and smtp relay, email marketing at scale for developers and enterprises. Of those, transactional email delivery and smtp relay and email marketing at scale for developers and enterprises are not what SurveyCTO is typically brought in for.
What can Mailgun do that SurveyCTO cannot?
SurveyCTO covers Offline collection, XLSForm authoring, Automated quality checks, Audio auditing.

Answered from the vendors’ own pages

Mailgun: 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.

Source
SurveyCTO: Do I pay per enumerator?

No. Users and devices are unlimited on every paid tier. You pay for monthly submissions, forms and storage.

Mailgun: 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.

Source
SurveyCTO: Is there a free version?

Yes, a permanent community subscription with 10 forms, 200 monthly submissions and 200 MB of storage, intended for testing and training rather than production.

Mailgun: 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.

Source
SurveyCTO: What happens if I exceed my submissions?

Extra credits are 100 US dollars per 1,000, with discounts of 20 per cent or more at volume. Plan the tier around your peak field month, not your average.

SurveyCTO: Can I choose where the data is stored?

Only on Pro and above. If data residency matters, budget for at least the Pro tier.

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