Build vs Buy: Why We Built Our Own Email Deliverability Monitoring Instead of Paying Postmark - Prime Automation Solutions

Build vs Buy: Why We Built Our Own Email Deliverability Monitoring Instead of Paying Postmark - Prime Automation Solutions

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    Home > Blog > Build vs Buy: Email Deliverability Monitoring

  # Build vs Buy: Why We Built Our Own Email Deliverability Monitoring Instead of Paying Postmark

  We evaluated five paid tools that range from $0 to $500 a month. Then we built our own. Here is the cost math, the tradeoffs, and what shipped.









      May 12, 2026
      •
      9 min read


    If your business sends email, you have a deliverability problem you probably cannot see. Welcome emails routed to spam. Password resets that never land. Quote attachments that get silently bounced. Marketing replies that go to junk because Google decided your sending reputation slipped last week. None of these show up in your sent folder. They show up as customers who never reply.

    For the last year, we have been operating dozens of sending domains across our hosting customers and our own products. Email is unavoidable infrastructure for any business that hosts a website. So we went shopping for a deliverability monitoring platform. We evaluated five of the obvious choices, did the math, and ended up building our own. This is the writeup.

    ## What "deliverability monitoring" actually means

    Before getting to the tools, the category needs a definition. Deliverability monitoring is not the same thing as sending email. Postmark, Mailgun, SendGrid, SES - those are senders. They put email on the wire. Deliverability monitoring is the layer that tells you what happened next:


      DMARC reports. The XML feedback Google, Microsoft, and other inbox providers send you, telling you which messages claiming to be from your domain actually authenticated correctly. Without parsing these, you cannot tell whether your legitimate mail is aligned or whether someone is spoofing you.
      Bounce and complaint events. Every send produces an outcome - delivered, bounced, marked as spam. Aggregating these per-domain over time is the only way to know if your reputation is sliding.
      Reputation signals from inbox providers. Google Postmaster Tools and Microsoft SNDS publish your domain reputation, IP reputation, and authentication pass rates. You need someone watching the graph.
      Policy enforcement. Are you actually on DMARC quarantine or reject? Or still on monitor-only because nobody pushed the button after warmup?


    A real deliverability platform does all four. A weak one does one or two and calls itself complete.

    ## The vendor landscape we evaluated

    Here is what we looked at, with rough 2026 pricing for a small fleet of sending domains:


      Postmark DMARC Monitor - free tier for basic DMARC report parsing, paid plans for richer analysis. Postmark is best-in-class at sending, but the deliverability monitoring product is a complement, not a full platform.
      dmarcian - $24 to $169 a month depending on report volume and domain count. Strong DMARC analysis. Does not aggregate your bounce or complaint events because it is not a sender.
      EasyDMARC - $39 to $239 a month at the SMB tiers. Cleaner UI than dmarcian. Same fundamental scope - DMARC reports, not full deliverability.
      GlockApps - $59 to $199 a month for inbox placement testing and reputation monitoring. Different angle: they simulate sends to seed addresses across providers and tell you where you landed.
      Mailgun Deliverability - bundled into their sending plans, roughly $35 to $90 a month for the analytics tier. You have to be sending through Mailgun for the data to flow.
      Valimail Monitor - free DMARC parsing, paid for enforcement. Targets enterprise. Sales-led.


    For one sending domain, you can stitch the free or cheapest tiers together for $0 to $50 a month. For a hosting business with a dozen customer domains plus our own product domains, the realistic cost was $200 to $500 a month across two or three vendors - because no single tool covers the whole problem.

    ## Why the math did not work for us

    $200 to $500 a month is not a lot of money in absolute terms. The reason we did not just sign up is that the math gets worse, not better, as we grow.

    Per-domain pricing punishes the customer mix we want. Our hosting customers each have their own sending domain. Every new hosting customer adds a domain to monitor. Vendor pricing scales with domain count, so the more customers we onboard, the more the deliverability bill grows - and the customer is paying us a fixed hosting fee. Margin compresses as we succeed.

    Data we cared about lives in three separate tools. DMARC alignment in one vendor, bounce events in another, inbox placement in a third. To answer a simple question like "did our 9 a.m. quote email get to its recipient and did our sending reputation move because of it," we would need to cross-reference three dashboards. That is operational drag we did not want to design around.

    Custom rules were not on the menu. We wanted to alert on patterns the vendors do not natively detect - for example, a customer's sending domain failing SPF alignment on a specific recipient host while passing on others, or a sudden uptick in soft bounces from a specific ISP that historically signals an impending block. These are queries you write against the raw data, not features you check off in a SaaS UI.

    The data is our customers' data. Our hosting customers trust us with their site, their email, and their business. The DMARC aggregate reports their domains receive belong to them. Routing all of that through a third-party SaaS introduces a data-sharing surface area that is hard to explain in a contract and harder to justify.

    ## What we built instead

    The stack is intentionally boring. Every piece is open source or already in our infrastructure:


      parsedmarc - the open-source DMARC aggregate and forensic report parser. Receives reports via IMAP, parses them, and emits structured records. Maintained, battle-tested, used by thousands of operators.
      AWS SES event destinations - bounce, complaint, delivery, reject, open, and click events fired to SNS, ingested into our metrics pipeline. This is just turning on a feature SES already gives you.
      SQLite for per-domain history - small footprint, no separate database service, full SQL access for ad-hoc queries.
      Prometheus and Grafana - the monitoring stack we already run for everything else. Per-domain dashboards, alerting on bounce rate over 2 percent, complaint rate over 0.1 percent, DMARC fail rate over 5 percent. Same dashboards our infrastructure already lives in.
      A FastAPI service with a few hundred lines of Python tying the above together and exposing an API for our other internal tools.


    Total engineer-time to ship the first useful version: about three working days. Ongoing operational cost: a few cents of disk and a handful of Prometheus scrapes. There is no per-domain pricing, no monthly invoice, no data leaving our infrastructure, and we can write whatever custom alert we want by adding a query.

    ## The honest tradeoff

    We are not telling you that you should build this. We are telling you that we built it because we host websites for other people, and the per-domain economics of paid deliverability tools eat into the margin on a hosting business. Different math for different shops.

    If you send email from one domain and you do not run hosting infrastructure for other businesses, pay Postmark or dmarcian and move on with your day. The free tier of Valimail Monitor or Postmark's DMARC tool will tell you 80 percent of what you need to know, and the paid tiers fill in the rest. Three or four hours of engineering effort is not worth the savings unless you have a structural reason to own the pipeline.

    The structural reasons we had:


      We operate many sending domains, not one. Per-domain pricing is a tax we wanted to remove.
      We already run the monitoring stack the dashboards needed to live in. Grafana was zero marginal cost. For us.
      Our hosting customers' DMARC reports are their data. Keeping it on our infrastructure is a privacy posture we can stand behind in writing.
      We needed custom alerts that the vendors did not expose. Writing SQL against your own database is faster than waiting for a feature request.


    If three or four of those apply to your situation too, building makes sense. If they do not, paying makes sense.

    ## What this means if you host with us

    Every PAS hosting plan now includes email deliverability monitoring on the sending domain attached to your site. DMARC report ingestion, SPF and DKIM alignment tracking, bounce and complaint dashboards, and reputation alerts run quietly in the background. If a problem appears - your reputation slips, a new mail flow starts failing alignment, your bounce rate crosses a threshold - we get the alert and we contact you. You do not need to know the difference between p=none and p=reject. We do.

    This is not a feature we charge extra for. It is part of how a hosting plan should work in 2026. Email is half of your customer relationship. If we are hosting your site, we are watching the deliverability too.

    If you are paying $50 to $500 a month elsewhere for this and not using it, that is a line item worth a second look. See what is included in our hosting, or reach out if you want to talk through your specific deliverability setup before deciding whether to switch.



      ### Want Email Deliverability Monitoring Included With Your Hosting?

      DMARC enforcement, reputation tracking, and bounce dashboards - bundled into every hosting plan, no extra invoice, no third-party tool needed.

      See Hosting Plans













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