Resend was fine until volume hitA per-email meter is flat right up until it is not.

A modern transactional API is a good product: a clean SDK, a generous low-volume tier, and none of the DNS and reputation setup a raw sending account demands on day one. For a prototype or a product with a few hundred users, the bill is a rounding error next to engineering time, and that is the right trade to make. Nobody should spend a week wiring up SES to send a hundred password resets a month.

The pricing that makes this easy is metered to your sends, which is fine while sends are small and becomes the whole story once they are not.

Rough monthly figures, checked July 2026. Your own Amazon SES account, sitting under an installed platform, against a typical per-email API ESP at the same volume.

The SES column stays close to $0.10 per 1,000 emails because that is what Amazon charges for the send itself; a platform sitting on top adds no per-email markup, only a fixed licence. The API ESP column climbs because its price is built to grow with your volume, which is the entire mechanism that made it feel free when your volume was small.

This is not a page arguing everyone should move. A prototype that sends almost nothing has no reason to open an AWS account for a bill that is already close to zero. A team that values the finished developer experience over the marginal dollar, and sends at a volume where the bill stays in the low tens, is making a defensible call by staying. The number that matters is not today's invoice, it is the slope of the line your product's growth is drawing under it.

The work is smaller than it sounds and mostly happens once. Map the transactional templates and sending domains already in use, verify that same domain on SES, and generate new API keys inside the account you control. Point the application's environment variables at the new endpoint, and, if the team wants confidence before cutting over fully, run both paths in parallel for a short window before retiring the old one.

None of that touches deliverability. The sending domain and its authentication records move with you; a mailbox provider judges the domain and its history, not which company's dashboard shows the send button.

Choosing between a per-email API and your own SES account is not a pure cost decision, even when the cost gap is real. The API buys a finished console, webhooks, and support you can email. Raw SES buys a lower ceiling on price and a sending path nothing outside your AWS account can suspend, in exchange for building or installing the layer that shows you your list, your templates, and your suppressions. Claims that one option is simply better skip that trade; the honest version is that it depends on which side of the volume curve your product sits on today, and where it is heading.

SendBunny installs the campaign, template and transactional layer directly into your AWS account, on top of your own Amazon SES, for a one-time $199 licence with optional one-click updates at $99 a year after the first. Sending stays at Amazon's roughly $0.10 per 1,000, with unlimited contacts and no per-email markup on top, which is the number that keeps the table above flat as volume climbs.