Two transactional email providers, compared on price, features and ratings, so you can pick fast.
Updated November 2026
THE VERDICT
Mandrill wins on developer experience and sending APIs. OneSignal Email wins on price and reviews.
Mandrill starts at $20 versus OneSignal Email's Free. OneSignal Email rates higher with developers (4.7 vs 4.2 on G2). Pick based on volume and team, and the scorecard below breaks down where each one leads.
Winner cells are tinted, green where Mandrill leads, violet where OneSignal Email does.
FAQ
Mandrill starts at $20 versus OneSignal Email's Free. Because pricing models differ by tier, the cheaper option depends on your monthly volume, so compare the pricing rows in the scorecard above.
Pricing is block based, where each block is 25,000 emails. Blocks cost $20 each for the first 20 blocks (up to 500,000 emails), then drop to $18, $16, $14, $12, and $10 per block at higher volumes. These charges are on top of a required Mailchimp Standard or Premium marketing plan, and dedicated IP addresses cost an additional $29.95 per month.
OneSignal provides official server SDKs for Node.js, Python, Java, Go, PHP, Ruby, C#, and Rust, all generated from the same OpenAPI specification for a consistent interface. It also offers a REST API and client SDKs for mobile and web. This makes it straightforward to send email and other channels from most common backend stacks.
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 Mandrill, OneSignal Email, or both, and switch providers without changing your code. Courier sits in front of every channel.
Pricing, plans and feature availability as of November 2026 and may change. Ratings are aggregated from public review platforms. Mandrill is Mailchimp Transactional.