Most platforms restrict you to a single domain on the free tier, and even the initial paid tiers are surprisingly stingy. Whenever I started a new experiment, I had to "kill" the email for a previous project just to reuse the domain slot. If a user tried to sign up or reset a password on an older project, it was effectively dead.
I built Simple Email API to stop this cycle. I wanted an email API that doesn't punish you for experimenting.
Two things I focused on:
1. Multi-domain by default You can add unlimited domains without being forced into a $20/month plan immediately. I’ve optimized the infrastructure to keep costs low so I can provide affordable pricing. You can keep your old projects alive while you build your next one.
2. Native Inbound (not an afterthought) Most APIs are built for outbound, and inbound feels like a complex add-on. Here, every email is "reply-ready" out of the box.
For Production: We have standard webhooks.
For Prototyping: We have a simplified onReceive callback. If you're building an AI agent or a quick script, you don't want to deal with webhook endpoints and secrets. You can get up and running with just an API key.
The goal is to be the simplest possible way to send and receive emails. I’m looking for brutally honest feedback.