Catalog entry · InboxRatio Editorial

Postmark

Postmark is a transactional email service — API and SMTP sending for application email — owned by ActiveCampaign, with the brand unchanged. postmarkapp.com served the product homepage directly when we verified it in August 2026. Its search demand sits below our usual tier-1 cutoff, but the service's standing in the transactional segment made it a deliberate inclusion for the full test cycle.

A free developer tier sends 100 emails per month and never expires. At our 50,000-email transactional volume, Basic costs $55/month (the same tier is $15 at the 10,000 step); event webhooks are available on all tiers, and overage runs $1.80 per 1,000 emails. Pricing checked 19 August 2026.

Deliverability: not yet tested. No inbox-placement score is shown until our seed-list cycle runs. The measurement protocol lives at how we test, and results land in the email deliverability ranking.

From our pricing dataset

Pricing at a glance

Tier	Monthly price	What's included
Free	$0/mo	100 emails/mo
Basic	$55/mo	50,000 emails/mo
Pro	$60.50/mo	50,000 emails/mo
Platform	$66/mo	50,000 emails/mo

Pricing checked 19 August 2026 · monthly billing, prices as shown by the vendor.

From our feature dataset

Deliverability capabilities audit

The 17 deliverability capabilities we check every vendor for — authentication help, IP management, list hygiene, and reputation tooling. This audits what Postmark documents; it is separate from our tested deliverability ranking.

14 of 17 documented capabilities

Yes:
SPF assistance
'emails sent through Postmark will always pass SPF by default' (Return-Path includes Postmark IPs/SPF record)
Yes:
DKIM setup
DKIM DNS record generated per sender signature/domain; required for domain verification
Yes:
DMARC support
'full DMARC support with custom Return-Path domains' — custom Return-Path CNAME fixes SPF alignment
Partial:
Dedicated IPpartial
Dedicated IPs listed; add-on $50/mo/IP, Pro+ plans AND >=300k emails/mo only
Yes:
Shared IP pools
Default sending on Postmark-managed shared IPs; promotional and transactional traffic ride 'parallel but separate sending infrastructure'
Not documented:
IP warmingnot documented
IP warm-up process not stated on fetched pages
Not documented:
Automated warmupnot documented
Not stated on fetched pages
Partial:
IP pools managementpartial
Message Streams separate transactional vs broadcast infrastructure; customer IP pools not stated
Yes:
Bounce management
'When emails are identified as Hard Bounce or Spam Complaint they are automatically deactivated from your list'

Yes:
Suppression lists
Deactivated addresses 'will be disregarded' on future sends
Yes:
Complaint management
Spam-complaint addresses auto-deactivated and not reactivatable
Yes:
Feedback loop handling
Complaints recorded when subscribers click 'This is Spam' at Yahoo/Hotmail/AOL etc. (mailbox-provider feedback) and auto-suppressed
Partial:
Reputation monitoringpartial
'Stellar deliverability... we vet every new sender carefully'; vendor-side reputation upkeep, no customer reputation dashboard stated
Not documented:
Blacklist monitoringnot documented
Not stated on fetched pages
Partial:
Deliverability analyticspartial
Bounce reporting/API with 45-day retention; delivery stats per server
Partial:
Deliverability consultingpartial
'help you follow deliverability best practices' — support-led guidance, no paid consulting product stated
Yes:
Domain authentication guidance
DNS setup resources for DKIM and Return-Path across common hosts/DNS providers

Items marked — are not documented by the vendor. In this category, silence is itself a signal. How we read vendor claims: methodology.

From our feature dataset

Postmark feature matrix

What the vendor documents, category by category. ◐ marks tier-gated or limited capabilities; — means the vendor does not document it.

Email5 of 6 documented

Partial:
Marketing campaignspartial
Broadcast Message Streams — 'route promotional messages like newsletters through a parallel but separate sending infrastructure'; no marketing-suite tooling
Yes:
Transactional email
Core product — 'Transactional Email'
Yes:
SMTP relay
'SMTP Service'
Partial:
Bulk sendingpartial
Broadcast streams for bulk/promotional sends; volume plans 10k-1.5M
Yes:
Email templates
'Email Templates' feature
Not documented:
Drag-and-drop editornot documented
Editor type not stated on fetched pages

Automation6 of 6 documented

No:
Email sequences
No marketing automation product — sending infrastructure only
No:
Drip campaigns
Not offered
Partial:
Event-based automationpartial
Webhooks push message events for customer-built automation; no built-in automation
No:
Behavioral automation
Not offered
No:
Workflow builder
Not offered
Partial:
Conditional logicpartial
Template variables/logic in email templates; no automation branching

AI6 of 6 documented

No:
AI email generation
No AI features stated on product pages
No:
AI subject lines
Not offered
No:
AI content optimization
Not offered
No:
AI segmentation
Not offered
No:
AI campaign recommendations
Not offered
No:
AI agent / assistant
Not offered

Personalization4 of 4 documented

No:
Segmentation
Not offered — no audience segmentation tooling
Partial:
Dynamic contentpartial
Templated messages with variable substitution
Partial:
Personalization variablespartial
Template model variables
No:
Behavioral targeting
Not offered

Analytics4 of 4 documented

Yes:
Opens & clicks
'Analytics & Retention' — message-event tracking incl. opens/clicks
No:
Conversion tracking
Not offered
Partial:
Campaign reportingpartial
Per-stream/server statistics and bounce reports (45-day default retention)
Partial:
Deliverability analyticspartial
Delivery/bounce statistics per server; no inbox-placement testing product

Developer features5 of 5 documented

Yes:
API
'Email API' with code examples; API on all tiers
Yes:
SMTP API
SMTP service
Yes:
Webhooks
'Webhooks' feature (event webhooks on all tiers per comparison table)
Yes:
SDKs / client libraries
'API libraries for pretty much every programming language' (Node.js, Python, Ruby, PHP, C#)
Yes:
Public API docs
Public developer documentation

Marketing platform7 of 7 documented

No:
CRM
Not offered — transactional email service
No:
Signup forms
Not offered
No:
Popups
Not offered
No:
Landing pages
Not offered
No:
Chatbots
Not offered
No:
SMS
Not offered
Partial:
Other channelspartial
Inbound email processing is the only additional channel

E-commerce5 of 5 documented

No:
Store integrations
Not offered — no store apps
No:
Cart recovery
Not offered
No:
E-commerce automation
Not offered
No:
Purchase tracking
Not offered
No:
Product recommendations
Not offered

Features checked 21 August 2026 · from vendor documentation and official feature pages.

Captured from the vendor website

Postmark in screenshots

Postmark website: homepage hero section — Postmark homepage, August 2026
Source: vendor website · 21 August 2026

Postmark website: product/features section — Homepage deliverability section ("Switching to Postmark")
Source: vendor website · 21 August 2026

Independent review platforms — shown as context; never part of our measured Deliverability Score

What users say

Capterra

4.7/5

35 reviews

Checked 21 August 2026

Trustpilot

2.2/5

45 reviews

Checked 21 August 2026

Weighted average 3.3/5 across 80 reviews.Limited review base

Shown as independent context — never part of our measured Deliverability Score

What others say about deliverability

Email Deliverability Report — Postmark deliverability dataExpert studyunknown
Across 76,208 test emails Postmark scored 92/100 with 78.00% inbox, 19.97% spam and 2.03% lost — third of 24 tested providers — but notably weakest at Gmail (74.37% inbox).
WP Mail SMTP — Postmark Review: Features, Pricing & DeliverabilityArticle1 June 2026
Calls Postmark's deliverability reputation among the strongest in transactional email, citing an independent test of ~98% inbox vs SendGrid's 95%, and in the reviewer's own ~12 test sends every confirmation email hit Gmail's primary inbox in under two seconds with none in spam, crediting message-stream separation and sender vetting.
EmailWarmup — Postmark Review: What Changed After ActiveCampaign?Article1 May 2026
Cites parallel-send testing showing 98.7% inbox placement for Postmark vs 95.3% for SendGrid and ~1.2s average delivery, rating core deliverability 4.5/5, but documents post-acquisition problems — unexplained account suspensions, 3-7 day approvals and degraded support — for an overall 3.7/5 (competitor-published, so a weak-independence source).
The Digital Bloom — B2B Email Deliverability Report 2025Expert study1 November 2025
Independent B2B benchmark (Nov 2025) measures Postmark at 43.66% inbox placement in Q1 2025 (down 13.24 pp YoY) — still the best result among the six ESPs it tracked, ahead of Amazon SES and SendGrid.
Hacker News — Postcard is now open source (Postmark deliverability discussion)Forum1 July 2025
Practitioners report declining Postmark deliverability: the project author moved from Postmark to SES because 'Postmark deliverability has been decreasing', and a self-described former Postmark advocate says 'postmark is a garbage now' and that SES is now on par or better.

Same primary category, from our catalog

Alternatives to Postmark

Brevo

Email marketing plus transactional email and SMTP relay on one platform; the European demand anchor in our catalog.

View profile →

SendGrid

Transactional email API and SMTP service operated by Twilio, with a separate Marketing Campaigns product; the transactional demand anchor.

View profile →

Mailjet

Email marketing with transactional API and SMTP sending, owned by Sinch; most of its measured demand sits in Europe.

View profile →

Selected by catalog rule — same primary category, same depth tier first, then catalog demand order. Never hand-picked.

Generated from our datasets — every value verified and dated

Frequently asked questions

What is Postmark?

Postmark is a transactional email service in the InboxRatio catalog, also covering smtp provider and developer email infrastructure. Its regional focus is Global.

How much does Postmark cost?

Paid Postmark plans start at $55/mo (Basic tier), prices as shown by the vendor, last checked 19 August 2026.

Does Postmark document its deliverability capabilities?

Postmark documents 14 of the 17 deliverability capabilities we audit every vendor for (authentication help, IP management, list hygiene, reputation tooling). This audits what the vendor documents — it is separate from our measured Deliverability Score, and undocumented items are themselves a signal. How we read vendor claims.

What do users say about Postmark?

Across 80 reviews on Capterra and Trustpilot, Postmark averages 3.3/5 (review-count-weighted). User ratings are shown as context only — never part of our measured Deliverability Score.

Has Postmark's deliverability been tested by InboxRatio?

Not yet — Postmark is in the queue for Cycle 0, our first seed-list test cycle across the whole catalog. We publish measured inbox-placement results only after a completed cycle, so this profile carries no Deliverability Score until then. How we test.

What are the main Postmark alternatives?

From our catalog, the closest alternatives are Brevo, SendGrid and Mailjet — services sharing Postmark's primary category (transactional email), selected by a neutral catalog rule, never hand-picked.