Deliverability insight from inside your sending infrastructure.
Most deliverability platforms are largely theoretical — a handful of seed and panel data points, then a lot of inference. Postmastery connects directly to your self-hosted or service-based sending infrastructure and surfaces what those platforms miss, backed by engineers who've spent careers inside high-volume email.
The problem
Why most deliverability tooling falls short.
I've spent 25+ years inside email — ESPs, MTAs, deliverability platforms, production tooling. The same gaps show up at almost every sender I talk to:
Seed lists don't tell you what really happened
A few hundred panel inboxes can't represent a send of tens of millions. By the time a seed-based score moves, real subscribers have already churned.
Inferred reputation, not measured behavior
Most platforms guess at IP and domain reputation from external signals. Mailbox providers throttle, defer and filter based on signals your own MTA already sees in real time.
Bounce and deferral reasons get flattened
ESP dashboards collapse rich SMTP responses into a handful of categories. The actual reason a Gmail or Yahoo MTA pushed back is sitting in your logs, unused.
Queue health is invisible
Retry behavior, per-destination concurrency, backoff and queue depth quietly shape inbox placement. None of it shows up in a third-party deliverability score.
FBL and complaint flows are siloed
Feedback loops, list-unsubscribe signals and complaint streams live in three different places. Without unifying them against your sends, patterns are easy to miss.
Dashboards without engineers solve nothing
A graph that says "reputation down" doesn't fix anything. You need people who've diagnosed this exact pattern at other senders and know what to change.
Why I'm recommending Postmastery
Telemetry from the infrastructure that actually sends your mail.
I've spent my career around the MTAs and ESP backends that move serious volume. Postmastery is the first deliverability platform I'm comfortable putting my name on, because it stops guessing — it reads what your own sending infrastructure already knows, and pairs that with engineers who've fixed these problems before.
Real data from your MTA
Not seed-list inference. Postmastery ingests the actual send, bounce, deferral and engagement stream from your sending infrastructure.
Works with the MTAs you actually run
Native fit for PowerMTA, KumoMTA, GreenArrow Email, Halon, MailerQ and Postfix — whether self-hosted or service-based. Postmastery speaks the protocols and log formats your stack already produces.
Deliverability engineers, not just dashboards
Behind the analytics is a team that has run deliverability for some of the largest senders in the world. You get a graph and a person who knows what to do about it.
Proven with ESPs and high-volume senders
Trusted by email service providers and enterprise senders where a half-day of bad placement is a real revenue event, not a curiosity.
How Postmastery works
From your MTA to a clear answer, in three steps.
Connect to your sending infrastructure
PowerMTA accounting files, KumoMTA, GreenArrow, Halon, MailerQ and Postfix logs, ESP backends, FBL feeds, list-unsubscribe streams. Postmastery meets your stack where it already is.
Stream real metrics into one view
Sends, bounces, deferrals, complaints and engagement are unified per IP, per domain and per campaign — with the actual SMTP responses preserved, not flattened.
Diagnose with engineers, not just a dashboard
Postmastery's deliverability engineers work with your team on reputation, throttling, placement and infrastructure decisions, using the data your MTA is generating right now.
What Postmastery sees that theoretical platforms miss
- Per-IP and per-domain throttling and concurrency behavior
- Real SMTP bounce and deferral reason codes, not generic buckets
- Queue depth, retry patterns and backoff in real time
- FBL, complaint and list-unsubscribe streams unified against sends
- Mailbox-provider-specific patterns across Gmail, Yahoo, Microsoft and more
- Reputation movement tied to actual events on your infrastructure
Postmastery services
More than a console — a deliverability and MTA team behind it.
Postmastery is unusual: the same company that builds the analytics also runs deliverability programs and operates sending infrastructure for some of the largest senders in Europe and North America. Two offerings sit alongside the Console:
Deliverability Consulting
Senior deliverability engineers who have spent careers inside ESPs and high-volume senders — not generalists reading the same public guidance you've already read. They work the problem with your team using your real metrics, not a generic checklist.
What makes it different
- Deliverability audits across IPs, domains, authentication and content
- IP and domain warm-up plans calibrated to your actual volume curve
- Direct relationships with mailbox providers when escalation is warranted
- Reputation recovery playbooks when something has already gone wrong
- Ongoing managed deliverability for teams without an in-house specialist
MTA Infrastructure
Postmastery designs, deploys and operates the sending infrastructure itself — across PowerMTA, KumoMTA, Halon, MailerQ and Postfix. That includes everything from a greenfield architecture to migrating an existing PowerMTA estate onto KumoMTA without losing reputation in the process.
What makes it different
- Architecture and sizing for PowerMTA, KumoMTA, Halon, MailerQ and Postfix
- Deployment, migration and upgrade work — including PowerMTA → KumoMTA moves
- Multi-IP, multi-domain and multi-tenant configurations done correctly
- Performance tuning: queueing, concurrency, retry logic and DNS
- Managed hosting and 24/7 monitoring for production sending environments
The combination is the point: the same engineers who tune your MTA also read its metrics in the Console and advise on deliverability. There's no hand-off between a "tooling vendor" and a "services vendor" — it's one team, one stack, one accountable owner.
About me
Why I'm the one introducing you to Postmastery.
I spent 10.5 years building the PowerMTA sales organization (Port25, then SparkPost), the MTA that grew to roughly 75% market share among email service providers. If your stack sends serious volume, there's a good chance PowerMTA is in it — and a good chance I had a hand in getting it there.
I then spent 5 years at GreenArrow Email working with major senders including Klaviyo, Marigold, ClickFunnels and Vercom (MailerLite) — the kind of operators where deliverability is the product, not a line item.
Today I'm a Fractional Consultant who partners with best-of-breed MarTech teams. I introduce Postmastery to senders because it matches unmatched insights with proven engineering resources to solve the most complex email deliverability problems.
Don't take my word for it
What Postmastery customers actually say.
A selection of verified customer feedback from postmastery.com/ratings.
"Postmastery is a great tool for email data visualisation at scale. For us, the key value is seeing all our email data in one place with effective drill-down capabilities."
"The Postmastery Console has been a really great tool for us to deliver on our promise of including deliverability as a service when using our email platform. It gives us an easy way to monitor and be more proactive about what we're seeing in terms of issues."
"Our deliverability rates have been improved by 50% since we started working with Postmastery. We are able to detect issues related to missing DNS, complaints, or with clients faster than before."
"An excellent training session and consultancy which brought together the high-level PowerMTA functions and bespoke consultancy together in perfect synergy."
"Postmastery Delivery Analytics is really the tool dedicated to emailing that allows us to get the best reading of our Postfix logs in real time."
"We're able to monitor and diagnose email deliveries of tens of thousands of users and exceed a 99% delivery rate solely thanks to Postmastery."
Let's talk
15 minutes on your deliverability stack.
No deck, no hard sell. Tell me how you're sending and what you're trying to measure, and I'll tell you whether Postmastery is the right fit.
- 15 minutes, on your calendar
- Booking a live Postmastery Console walkthrough if it's a fit