A boring email infrastructure company that has been quietly running since 2008

We are OS Domains GmbH, an Austrian limited liability company headquartered in Vienna at Fleischmarkt 1, 1010, operating email sending infrastructure since 2008. The company has been profitable every year since founding, holds IP allocations across IPv4 and IPv6, and runs production infrastructure in seven datacenter locations: London, Amsterdam, Frankfurt, Strasbourg, Vienna (HQ), Dallas, and Panama. The Panama site is our datacenter for the offshore-hosting product specifically; the rest of the operation is EU-jurisdiction.

The company is not a startup, has never raised venture capital, has no exit pressure from investors, and is owned by the operating team. This matters because the email infrastructure category is full of products built on 18-month VC clocks where the eventual outcome is acquisition or shutdown, neither of which is good for customers running production sending. We have outlasted multiple cohorts of well-funded competitors by being the boring profitable option that does not need to grow at any specific velocity. Our customer churn rate is below 4 percent annually for paid plans; the operational reasons customers leave are usually acquisitions or fundamental changes to their email needs, not dissatisfaction with our service.

What we do is operate the layer between your application and the receiver-side mailbox: SMTP, MTAs, IP reputation, DNS authentication, deliverability monitoring, and the operational work that makes outbound email actually arrive. We do not write content, we do not run marketing automation, we do not maintain customer lists for you, and we do not build the application that triggers the sends. Those things are your work or your customer's work. Our scope is the infrastructure that handles whatever your application asks it to send. The boundary is clean and we maintain it deliberately because it lets us be excellent at one specific layer rather than mediocre across many.

The customer base is roughly 60 percent EU senders (where the Schrems II positioning is the deciding factor for procurement), 25 percent global senders running cold email or managed deliverability operations (where the operating maturity matters more than jurisdiction), and 15 percent specific high-volume use cases (transactional pipelines for large SaaS, ESP-style multi-tenant operations, regulatory-compliant senders in financial services and healthcare). The split has been stable for several years; we have not been chasing a vertical, we have been serving the customers who arrive with our product profile.

Worth saying explicitly about what we are not. We are not a marketing automation platform, not a CRM, not a customer engagement suite, not a tool that helps you write better emails. We are not Mailchimp, not HubSpot, not ActiveCampaign, not Customer.io, and we are not building toward becoming any of those. The application layer is full of competent vendors and we have no business competing in that category. Senders who arrive looking for an all-in-one platform get redirected to the right vendor for their actual need; we serve the senders who already have their application layer figured out and need infrastructure that will not let them down.

The pricing philosophy is also deliberately boring. Recurring products bill monthly with annual prepay discount; one-time engagements bill at signing with the documented warranty terms; custom enterprise contracts get negotiated upfront and signed with clear SLAs. We do not run usage-based pricing with surprise overage bills, we do not require multi-year commitments to access reasonable rates, we do not discount aggressively for new customers and quietly raise prices later. The pricing is what it says on the website, the engagement scope is what it says in the contract, and the relationship works because both sides know what the other side committed to.

And worth saying about scale. We are not the cheapest option in our category for solo founders or small startups, and we do not pretend to be. Below 50,000 emails per month, the right answer is usually a free tier of a major ESP or a basic shared SMTP plan; we will tell you that on a sales call. The customers we want, and the ones we serve well, are sending 100,000+ emails per month, running multi-domain operations, or have specific requirements (jurisdiction, monitoring depth, custom MTA configurations) that mass-market ESPs cannot accommodate. About 20 percent of inquiries get redirected to other vendors during the discovery call because they are too small for our cost structure to make sense; this is fine and the operational discipline of saying so keeps the customer base aligned with our capabilities.

One more clarification about how the catalog evolved. The fifteen products on the catalog today did not arrive in one launch. Each product was built in response to a customer asking for it, validated against several customers with the same need, and added to the catalog when the operational tooling was mature enough to support it as a documented offering. The migration service launched in 2018 because customers leaving Mandrill needed a structured engagement; the pre-warmed inboxes product launched in 2023 because cold email customers needed mailbox-level reputation; the deliverability monitoring product became a standalone offering in 2021 because external customers wanted access to the dashboard our sending customers already saw. The catalog reflects 17 years of customer-driven development rather than aspirational product roadmap planning.