useSend

What useSend does

useSend, previously called Unsend, describes itself as open source sending infrastructure and as an alternative to Resend, SendGrid, Mailgun and Postmark. Its core job is transactional email: your application sends messages through a REST API, typed SDKs for TypeScript, Python, Go and PHP, or an SMTP relay, and useSend records delivery, opens, clicks, bounces and complaints.

On top of that it manages contacts and marketing email. Contacts live in contact books, each with its own subscription status per contact, custom variables and optional double opt-in, where new contacts stay pending until they confirm through a signed link that expires after seven days. Campaigns are written in a visual editor modeled on a document editor, can reuse templates and insert contact variables with fallback values, and can be scheduled, paused and resumed. Every campaign must include the recipient-specific unsubscribe link, and a suppression list built from bounces and complaints applies to both transactional and marketing mail.

How sending works

useSend sends through Amazon SES, as its README openly says many email products do, and uses Amazon SNS to receive delivery status. On the hosted service this is handled for you. When self-hosting, you connect your own AWS account, choose an SES region and make the application’s callback URL reachable from the internet so status updates arrive.

Self-hosting useSend

The project publishes a Docker image and a production Docker Compose file that runs the app with PostgreSQL 16, Redis 7 and MinIO. Besides AWS credentials with SES and SNS access, you need a GitHub or Google OAuth app, because those are the documented login methods; email and password login is not available yet and the docs invite contributions for it. Stored email content is kept indefinitely by default, but a setting can clear message bodies, attachments and headers after a number of days while keeping delivery history. A Railway template is also offered.

Hosted version

The developers run a hosted service at app.usesend.com. The free tier limits daily and monthly sending and allows one contact book, one domain and one team member. The paid plan is usage based, with marketing and transactional emails priced per email; the site stresses that you pay for sending rather than for storing contacts.

Limitations

The README still describes useSend as being in beta. Sending depends on Amazon SES and SNS whether hosted or self-hosted. The documentation does not cover automation sequences, signup form builders or segmentation beyond contact books, so it is not a full replacement for a newsletter platform or a marketing automation tool. Requiring an OAuth app to log in to a self-hosted instance is an extra setup step.

Who it suits

useSend suits developers who want a single open source service for their application’s transactional email and for occasional product updates or newsletters to users. Teams that mainly run newsletters with signup forms should look at listmonk or Keila, and those who need lifecycle workflows for a product at Plunk.