whats-best.ai

Transactional Email · head-to-head

Mailgun vs Postmark

As of 2 Nov 2026, the panel rates Mailgun 2/5 and Postmark 3/5 in Transactional Email. Weighted by what each judge cares about, 2 of the 6 judges pick Mailgun and 4 pick Postmark. Postmark scores higher on 7 of 7 criteria (Sending API, SMTP & developer experience, Deliverability & sender reputation, Reliability, accounts & support, plus 4 more). Provenance — Mailgun: Rest of world; Postmark: Rest of world. Ratings are the AI panel’s opinion, formed from public evidence: how scores are made.

Mailgun

Rest of world

Panel rating

Sovereignty: not determined

Full evaluation →

Postmark

Rest of world

Panel rating

Sovereignty: not determined

Full evaluation →

The short answer

Postmark's widest leads are the sending API (7.0 to 4.0, six judges lean Postmark) and deliverability (7.5 to 4.5, four lean Postmark, two tie); its means also lead on observability, reliability and accounts, sovereignty and pricing transparency. Mailgun draws more judge leans on data and security, sovereignty and pricing transparency — three to two with one tie on each — even where Postmark's means run higher. Weighted totals split four to two: the developer (6.8 to 6.4), agency lead (6.4 to 6.2), data protection officer (5.8 to 0) and skeptic (6.2 to 0) carry Postmark; the platform engineer (6.5 to 6.4) and ecommerce operator (6.6 to 6.2) carry Mailgun. On sovereignty, Mailgun's pages show a published data processing agreement with standard contractual clauses under Swedish law and a selectable EU region, beside Texas-law contracting; Postmark's show Illinois law and United States storage, with no EU hosting region found on the captured pages.

Choose Mailgun if

  • Your team follows the bench lean on data and security, where three judges lean Mailgun, two lean Postmark and one ties.
  • You contract under EU terms: Mailgun's captured pages publish a data processing agreement with standard contractual clauses under Swedish law and an EU region the customer must select, and sovereignty leans Mailgun three to two.
  • You need a written uptime commitment: Mailgun's pages carry a 99.99% monthly uptime guarantee, while we found no SLA information on Postmark's captured pages.
  • Your reviewers match the platform engineer or ecommerce operator, whose weighted totals read 6.5 to 6.4 and 6.6 to 6.2 for Mailgun.
  • You send low volumes first: Mailgun's pages list a free tier at 100 emails/day.

Choose Postmark if

  • You build against the sending API first: Postmark's mean is 7.0 to Mailgun's 4.0, with six judges leaning Postmark.
  • Deliverability decides the purchase: Postmark's mean is 7.5 to 4.5 (four judges lean Postmark, two tie), resting on manual vetting of new senders, free custom Return-Path and DKIM, and separate infrastructure for transactional and broadcast traffic.
  • You compare starting prices across pages: Mailgun's captured pages give different figures for the starting price — $15/month for 10,000 emails versus Foundation at $35/mo — while Postmark's pricing transparency mean is 7.0 to 5.2.
  • Your operations lean on webhooks: the reliability and accounts mean is 6.2 to 4.0 (three judges lean Postmark, three tie), with strong webhooks and redundancy cited in the verdict.
  • Your operations run in the United States: Postmark's captured pages state personal information is stored in AWS and Deft data centres in the United States.

Read this comparison as one judge. Each weighs the same scores by what they care about.

The bench's picks

Same scores, different priorities: each judge's weighting applied to both products. The split is the finding.

Criterion by criterion

Mailgun Postmark Bench average per criterion. Each label leads to its row in the table.
Scores per criterion, in stars out of 5
Criterion Mailgun Postmark
Sending API, SMTP & developer experience 2 of 5 3.5 of 5
Deliverability & sender reputation 2.5 of 5 4 of 5
Message logs, events & webhooks 2.5 of 5 3.5 of 5
Message data, retention & security 2.5 of 5 3 of 5
Reliability, accounts & support 2 of 5 3 of 5
European sovereignty 1.5 of 5 2 of 5
Pricing transparency 2.5 of 5 3.5 of 5
Criterion Mailgun Postmark The bench leans
Sending API, SMTP & developer experience Postmark, 6 of 6 judges
Deliverability & sender reputation Postmark, 4 of 6 judges
Message logs, events & webhooks Postmark, 2 of 6 judges
Message data, retention & security Mailgun, 3 of 6 judges
Reliability, accounts & support Postmark, 3 of 6 judges
European sovereignty Mailgun, 3 of 6 judges
Pricing transparency Mailgun, 3 of 6 judges

Stars show the bench average per criterion; the lean counts which product each judge scored higher. Open a judge's tab for their reasoning on both sides.

Sovereignty, side by side

Dimension Mailgun Postmark
Legal entity Not determined Not determined
Hosting location Not determined Not determined
Hosting options Not determined Not determined
Open source Not determined Not determined
Data processing agreement Not determined Not determined
Transfer impact assessment Not determined Not determined

Facts, side by side

Only facts both products carry under the same definition — anything else would not be a fair row.

Compliance · Dpf certification Mailgun Technologies, Inc. · yes · yes1

captured 1 Nov 2026 · Report an error

yes · yes · yes2

captured 1 Nov 2026 · Report an error

Compliance · GDPR yes3

captured 1 Nov 2026 · Report an error

yes4

captured 1 Nov 2026 · Report an error

Compliance · GDPR page yes · yes5

captured 1 Nov 2026 · Report an error

yes6

captured 1 Nov 2026 · Report an error

Compliance · Security measures yes · yes · yes1

captured 1 Nov 2026 · Report an error

yes2

captured 1 Nov 2026 · Report an error

Data · Return deletion customer responsible for retrieving copy prior to termination · yes · yes · yes7

captured 1 Nov 2026 · Report an error

yes8

captured 1 Nov 2026 · Report an error

Integrations · Webhooks Webhooks push real-time email event data to applications9

captured 1 Nov 2026 · Report an error

Delivery · Bounce · Spam complaint · Open tracking · Click · Subscription change · Inbound · yes10

captured 1 Nov 2026 · Report an error

Legal · Copyright 2026 · Mailgun11

captured 1 Nov 2026 · Report an error

ActiveCampaign, LLC12

captured 1 Nov 2026 · Report an error

Legal · DPA available yes3

captured 1 Nov 2026 · Report an error

yes6

captured 1 Nov 2026 · Report an error

Legal · Entity Mailgun · Mailgun Optimize · Mailjet · Email on Acid · Sinch AB (publ) or its subsidiaries1

captured 1 Nov 2026 · Report an error

AC PM, LLC · Postmark Terms of Service13

captured 1 Nov 2026 · Report an error

Legal · Liability cap fees paid for affected services in preceding 12 months14

captured 1 Nov 2026 · Report an error

fees paid in the 3 months preceding the claim13

captured 1 Nov 2026 · Report an error

Pricing · Free 100 emails/day · 015

captured 1 Nov 2026 · Report an error

0 · 100 · no16

captured 1 Nov 2026 · Report an error

Product · Analytics Real-time opens, clicks, bounces analytics17

captured 1 Nov 2026 · Report an error

yes18

captured 1 Nov 2026 · Report an error

Product · Breach notification written, as soon as reasonably practicable, in accordance with applicable law · yes7

captured 1 Nov 2026 · Report an error

without undue delay · yes8

captured 1 Nov 2026 · Report an error

Product · Status page Unexpected service interruptions are notified via a status page19

captured 1 Nov 2026 · Report an error

yes16

captured 1 Nov 2026 · Report an error

Product · Templates Dynamic templates17

captured 1 Nov 2026 · Report an error

yes · yes16

captured 1 Nov 2026 · Report an error

Product · Trial 3015

captured 1 Nov 2026 · Report an error

no16

captured 1 Nov 2026 · Report an error

Product · User roles 515

captured 1 Nov 2026 · Report an error

yes16

captured 1 Nov 2026 · Report an error

Product · Webhooks yes20

captured 1 Nov 2026 · Report an error

yes · yes16

captured 1 Nov 2026 · Report an error

Questions about Mailgun and Postmark

Which is better, Mailgun or Postmark?

As of 2 Nov 2026, the panel rates Postmark higher: 3/5 against 2/5. Weighted by what each judge cares about, 2 of the 6 judges pick Mailgun and 4 pick Postmark. Which one fits depends on the criteria that matter to you; the table on this page shows both side by side, and each judge’s reading has its own page. Both were scored by the same AI bench under the same rubric, from public evidence only, as the methodology describes.

Is Mailgun or Postmark European?

Mailgun is not European by provenance (Rest of world). Postmark is not European by provenance (Rest of world). Provenance is read from each company’s own legal pages: who builds it and who owns it.

Where do Mailgun and Postmark store customer data?

Per the vendors’ own pages as captured — Mailgun: Default not stated; pages mention the US, the EU, United States and Europe. Postmark: its pages as captured do not say.

Do Mailgun and Postmark have a free plan?

As of 2 Nov 2026, both vendors’ own pages state a free plan. Each product page links the pricing page it was read from.