Two transactional email providers, compared on price, features and ratings, so you can pick fast.
Updated October 2026
THE VERDICT
OneSignal Email wins on deliverability and compliance. Postmark wins on developer experience and cost at scale.
OneSignal Email starts at Free versus Postmark's $10. OneSignal Email rates higher with developers (4.7 vs 4.6 on G2). Pick based on volume and team, and the scorecard below breaks down where each one leads.
Winner cells are tinted, green where OneSignal Email leads, violet where Postmark does.
FAQ
OneSignal Email starts at Free versus Postmark's $10. Because pricing models differ by tier, the cheaper option depends on your monthly volume, so compare the pricing rows in the scorecard above.
OneSignal's paid Growth plan starts at $19 per month and includes 20,000 free email sends per month, with additional email billed at $1.50 per 1,000 sends. Pricing applies to the overall platform rather than email alone, and higher volumes and features move to Professional and Enterprise plans. There is no email-only pricing tier.
Postmark offers a free developer plan that includes 100 emails per month. It does not require a credit card and does not expire, but sending stops once the 100 email limit is reached. This tier is intended for testing and development rather than production traffic.
Yes. Many teams route different message types through different providers or fail over between them. Courier lets you send through both behind a single API and switch providers without changing your code.
Why not both?
Use both behind one API.
Route OneSignal Email, Postmark, or both, and switch providers without changing your code. Courier sits in front of every channel.
Pricing, plans and feature availability as of October 2026 and may change. Ratings are aggregated from public review platforms. Postmark is an ActiveCampaign product.