# transactional email integrations for AI agents

> 8 transactional email apps the Definable agent workforce can read from, write to, and act on inside a multi-agent workflow.

## Count

**8** transactional email integrations on Definable. Every one is callable from any workflow on every plan — no per-app limits.

## How the agent team uses transactional email integrations

When the Builder agent reads a prompt that involves transactional email work, it assembles specialists from the team — Researcher, Writer, Designer, Engineer, Distributor — and routes transactional email tool calls through the **Distributor specialist**. The Researcher pulls context, the Writer or Designer produces the output, the Distributor pushes the result into the user's transactional email tool of choice. The Verifier checks every call and self-heals on rate limits, schema drift, or auth refresh.

The Builder picks the right transactional email integration per workflow based on what the user has connected — no manual mapping required.

## Apps in this category

- **Loops.so** — The email platform for modern SaaS. — https://definable.ai/apps/loops_so/
- **MailerSend** — MailerSend is a transactional email service designed for developers to integrate email sending capabilities into their applications. — https://definable.ai/apps/mailersend/
- **Mailtrap** — Email Delivery Platform for testing and sending transactional emails — https://definable.ai/apps/mailtrap/
- **Postmark** — Postmark is an email delivery service that enables developers to send transactional emails with high deliverability and detailed analytics. — https://definable.ai/apps/postmark/
- **Resend** — The universal API for sending emails. — https://definable.ai/apps/resend/
- **SendGrid** — SendGrid is a cloud-based email delivery platform providing transactional and marketing email services, with APIs for integration, analytics, and scalability — https://definable.ai/apps/sendgrid/
- **Smtp2go** — SMTP2GO is a reliable email delivery service that ensures your emails reach recipients' inboxes efficiently. — https://definable.ai/apps/smtp2go/
- **Unione** — UniOne is an email delivery service offering a versatile Web API and SMTP API for sending transactional and marketing emails. — https://definable.ai/apps/unione/

## Related

- HTML page: https://definable.ai/apps/category/transactional-email/
- All integrations: https://definable.ai/apps/
- Workflow (multi-agent loop): https://definable.ai/workflow/
- Apps llms.txt index: https://definable.ai/llms-apps.txt