As of 2 Nov 2026, the panel rates Lettermint 3.5/5 and Postmark 3/5 in Transactional Email. Weighted by what each judge cares about, 4 of the 6 judges pick Lettermint and 1 picks Postmark, 1 calls it a tie. Lettermint scores higher on 3 of 7 criteria (European sovereignty, Message data, retention & security and Message logs, events & webhooks). Postmark scores higher on 4 of 7 criteria (Pricing transparency, Deliverability & sender reputation, Reliability, accounts & support, plus 1 more). Provenance — Lettermint: EU-Made; Postmark: Rest of world. Ratings are the AI panel’s opinion, formed from public evidence: how scores are made.
Six criteria, two clear poles. Lettermint is ahead on sovereignty, 8.7 against 4.0, with 6 judges leaning Lettermint and 0 leaning Postmark; its verdict cites EU-only hosting, storage and processing on the vendor's own infrastructure and an automatically applicable Article 28 GDPR data processing agreement, while Postmark's cites contracting under Illinois law and storage in United States data centres. Data and security: 7.2 against 6.0, 6 judges to 0. Postmark is ahead on pricing transparency, 7.0 against 3.8, 6 judges to 0, and on deliverability, 7.5 against 6.8, where 3 judges lean Postmark and 3 tie. Observability leans Lettermint 3 judges to 0 with 3 ties; sending API and reliability and accounts lean Postmark 2 judges to 0 with 4 ties each. Weighted totals span 6 to 7.3 for Lettermint and 5.8 to 6.8 for Postmark, the developer's tie at 6.8 to 6.8; there is no overall winner.
Choose Lettermint if
You need EU-only hosting, storage and processing on the vendor's own infrastructure, plus an automatically applicable Article 28 GDPR data processing agreement — sovereignty leans Lettermint 6 judges to 0, 8.7 against 4.0.
Your security review requires independently audited ISO/IEC 27001:2022 certification — data and security leans Lettermint 6 judges to 0, 7.2 against 6.0.
Your subprocessor list must stay short: the verdict names only UpCloud and Postmastery in the Netherlands and OVH Cloud in Germany as handling email.
You are a data protection officer — the weighted total reads 7.3 for Lettermint against 5.8 for Postmark.
You want the higher observability mean — 3 judges lean Lettermint, 0 lean Postmark, 3 tie, 7.0 against 6.5.
Choose Postmark if
You need published prices to budget from — pricing transparency leans Postmark 6 judges to 0, 7.0 against 3.8; Lettermint's captured pricing page shows the free tier's 300 monthly emails but no euro prices for paid plans.
Deliverability is your top priority — 3 judges lean Postmark, 0 lean Lettermint, 3 tie, means 7.5 against 6.8, resting on manual vetting of every new sender and free custom Return-Path and DKIM.
Your team builds against the sending API — means 7.0 against 6.7, with 2 judges leaning Postmark and 4 tying.
You are an agency lead — the weighted total reads 6.4 for Postmark against 6 for Lettermint.
You want reliability documentation — reliability and accounts leans Postmark 2 judges to 0 with 4 ties, 6.2 against 5.7, and no public status page or incident history was found for Lettermint.
Read this comparison as one judge. Each weighs the same scores by what they care about.
The Shop Operator
Runs a Shopware shop for kitchen equipment in Germany and Austria with 900 orders a week. Order confirmations, invoices and shipping notices went out through the hosting provider's mail server until a customer found theirs in spam and the support inbox filled up. Wants guided SPF and DKIM set-up a non-specialist can follow, a plugin for the shop, order mail kept apart from the newsletter, and someone to ask when Gmail starts refusing.
Lettermint
This judge's pick
Postmark
Criterion by criterion
Sending API, SMTP & developer experience
Lettermint
The SMTP relay is documented down to host, ports and authentication, and there are official SDKs for PHP, Laravel, Symfony, Python, Node, Go, Java,.NET, Rust and Elixir, plus batch sending up to 500 emails per request, a sandbox mode, scheduled sending and an OpenAPI schema to download. We found no public information on stored templates with variables and versions, on idempotency keys for sending, or on a migration guide from named competitors.
Postmark
The captured pages document a REST API and an SMTP relay with named host and port, official libraries for TypeScript, Node, Python, Ruby, Rails, PHP,.NET and Java maintained by the vendor, framework guides for Laravel, Rails, Express, Django and Craft CMS, a WordPress plugin that overrides wp mail, batch sending up to 500 messages per call, a test-token mode that does not deliver, inbound email parsed to a webhook, a documented CLI and migration guides from SendGrid, Mailgun and others. For my Shopware shop this means sending via SMTP or REST is well covered. We found no public information on idempotency keys or scheduled sending, which is what keeps this just below the top anchors.
Deliverability & sender reputation
Lettermint
SPF, DKIM and DMARC are required before you can send, the DKIM key is hosted and rotated for you, a CNAME-based return path needs no manual SPF record, and transactional mail and newsletters go out on separate, already-warmed IP pools — exactly the separation I need between order confirmations and campaigns. Hard bounces are suppressed automatically, spam scores and a live Time to Inbox page per mailbox provider are published, and dedicated IPs exist as an add-on from 300,000 emails a month. We found no public information on vetting of senders on shared pools, feedback loops, DMARC reports or an explicit statement on the Gmail and Yahoo bulk-sender rules.
Postmark
This is what my spam-foldered invoices need: the pages describe SPF, DKIM and DMARC made easy to set up with a free custom Return-Path and DKIM domain, every sender manually vetted one-on-one, transactional and broadcast mail on completely separate infrastructure including IP ranges, and dedicated IPs with Postmark-managed warm-up, blocklist monitoring and feedback loops handled for you. Delivery times are published on a Time to Inbox page and the status page shows real-time delivery metrics. We found no public information on custom tracking domains or an explicit statement of compliance with the Gmail and Yahoo bulk-sender requirements, so I stop one step short of the top.
Message logs, events & webhooks
Lettermint
Email Activity lets me search messages by recipient, subject, status, project, route, tag and date range, open the event timeline plus the source, HTML and plain text of each send, and the Team API serves messages, per-recipient events and content over HTTP. Webhooks cover 22 event types including delivered, hard bounce, soft bounce and spam complaint, are signed with HMAC-SHA256, and retry on a documented schedule of twelve attempts over roughly fourteen hours with manual retry from the dashboard. Retention is a stated 28 days for message history, and we found no public information on alerts for bounce or complaint spikes, on extending or configuring that retention, or on streaming events to a log tool.
Postmark
Webhooks cover delivery, bounce, complaint, open, click and inbound with a fully documented retry schedule, retry-remaining and trace headers, per-event-type health tracking and even a webhook statistics API, while full message content is kept 45 days by default, adjustable from 7 to 365, and an observer role can review history without edit rights. That is exactly what I want when a support colleague has to check why an invoice bounced. The captured pages state plainly that HMAC webhook signatures are not supported, and we found no public information on bounce or complaint spike alerts or on exporting events to an external log tool.
Message data, retention & security
Lettermint
The data processing agreement states exactly what is kept per message — content, attachments, recipient addresses, metadata and events for 28 days, analytics events for 90 days, logs for no more than 14 days — and email content can be hidden per project or route in the dashboard. Delivery uses TLS 1.2 or higher with an enforced-TLS option per route or for a single email, data is encrypted at rest, project API tokens carry IP allowlists, and an ISO 27001:2022 certificate sits in a public Trust Center. We found no public information on two-factor authentication or single sign-on for the dashboard, on deletion of a recipient's data via the API, or on a vulnerability disclosure programme.
Postmark
What is stored is documented — full message content for 45 days, adjustable from 7 to 365 days, statistics indefinitely — open and link tracking can be switched off per message, encryption at rest is stated, two-factor authentication is on every plan including the free one, IP allowlisting exists, a data-removal API and a published DPA are available, and the data centres are SOC 2 certified. As a German shop two things worry me in the captured pages: the terms state the vendor may view, copy and internally use messaging content to train and improve the service, and outbound TLS is opportunistic only with no customer control over it. We found no public information on SSO or a dashboard audit log.
Reliability, accounts & support
Lettermint
Projects with their own API tokens separate my shop's order mail from other applications, and the role system is genuinely granular: Owner, Admin and Member plus custom roles, with project access assignable per member. Support runs by ticket, email and Discord from an EU-based team, and enterprise customers on Pro get a written service level agreement with uptime and response-time guarantees. We found no public information on a status page with incident history, on mail queueing during outages, or on a Shopware plugin — WordPress and Symfony Mailer are the named platforms.
Postmark
Redundant data centres in multiple locations with N+2 redundancy and geographic load balancing are described, separate servers with their own limits and up to ten message streams each let me keep order mail apart from anything else, three roles plus per-server permissions including an observer cover my team, support is included at no extra charge, and migration guides exist from named competitors. We found no public information on an uptime SLA, incident history, support response times or mail queueing during outages. A WordPress plugin is documented, but we found no public information on a Shopware plugin, and the terms reserve the right to terminate any account at any time without notice — a real risk when all my order confirmations flow through one pipe.
European sovereignty
Lettermint
A Dutch company in Zwolle, founder-owned with no investors, sends from its own EU network under its own IP addresses with mail processed and stored only in the EU and encrypted backups at a separate provider in Germany. Every subprocessor is listed with its location and whether it touches email — UpCloud in the Netherlands, OVH Cloud in Germany, Postmastery in the Netherlands, with Aikido and Mistral in Europe having no email access — and the Article 28 data processing agreement applies automatically and is countersigned on request. Data export in a machine-readable format is documented, but we found no public information on documented deletion beyond a 30-day retrieval window after termination, which keeps it from the very top.
Postmark
The contracting entity is AC PM, LLC under Illinois law with ActiveCampaign, LLC as owner, all personal information is stored on AWS and in a data centre near Chicago, and the terms require consent to processing and storage in the United States and other countries; we found no public information on an EU hosting region for messages or logs. On the positive side there is a published DPA with Standard Contractual Clauses under Irish law, an Article 27 EU representative in Kiel, and a sub-processor list with change notification. For my German and Austrian customers this means the whole sending chain, including message content, runs through the US with contractual safeguards rather than EU processing.
Pricing transparency
Lettermint
The free tier's 300 emails a month, the per-plan feature gates, the 28-day message history on every plan and billing in euros excluding VAT are public, with no credit card and cancellation at any time. But the captured pricing page gives no euro amounts for the paid tiers, describes the overage only as a small fee, and names the dedicated IP and bring-your-own IP as add-ons with no figures, so I cannot compute my annual cost for roughly 4,000 transactional mails a month from the public pages.
Postmark
All four tiers are priced publicly — Free at $0.00/mo with 100 emails, Basic at $15.00/mo, Pro at $16.50/mo, Platform at $18.00/mo — each with a stated extra-email rate per thousand, dedicated IPs at $50/month per IP with no setup fees, custom retention starting at $5/month, DMARC monitoring at $14/month per domain, no rollover of unused volume, and support never charged extra. The pages state that annual plans are not offered yet and high-volume pricing is by contact. We found no public information on the included monthly volume of the paid tiers beyond the entry level or on VAT treatment, which is what keeps the annual cost for my roughly 900 orders a week from being fully computable from public pages alone.
Sovereignty, side by side
Dimension
Lettermint
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.
As of 2 Nov 2026, the panel rates Lettermint higher: 3.5/5 against 3/5. Weighted by what each judge cares about, 4 of the 6 judges pick Lettermint and 1 picks Postmark, 1 calls it a tie. 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 Lettermint or Postmark European?
Lettermint is European (EU-Made). 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.
Do Lettermint 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.