---
title: Transactional Email API Guide | SendHQ
description: A practical guide to sending passwords, receipts, alerts, and other product-triggered email reliably.
canonical: https://sendhq.cc/guides/transactional-email-api
last-updated: 2026-08-24
---
# Transactional Email API Guide

A practical guide to sending passwords, receipts, alerts, and other product-triggered email reliably.

Transactional email is triggered by a user or system action: a password reset, receipt, verification link, alert, or status update. It should be sent from a verified identity, be observable, and remain separate from promotional mail.

## What this means in practice

- Action-triggered messages such as receipts and password resets
- Verified sender identities and aligned SPF, DKIM, and DMARC
- Per-message delivery responses and event records
- Clear separation between transactional and promotional use

## Implementation checklist

1. List every product event that must result in an email.
2. Define a stable template and idempotency strategy for each event.
3. Verify the sending domain before enabling production sends.
4. Monitor bounces and complaints, then suppress unsafe destinations.

## Questions teams ask

**What counts as transactional email?**

Messages needed to complete or communicate about a user action, such as account verification, receipts, security alerts, and password resets.

**Can I send marketing email through a transactional API?**

Only if the provider and recipient-consent model support it. Keep promotional traffic, opt-outs, and reputation controls separate from product-critical mail.

## Continue learning

- [Email API: Send, Receive, and Track Transactional Email](https://sendhq.cc/guides/email-api.md): Understand what an email API does, how sending and inbound receiving work, and what to evaluate before choosing one.
- [How to Send Email with an API](https://sendhq.cc/guides/send-email-with-api.md): A step-by-step approach to authenticated API email sending, testing, and production safety.
- [How to Receive Email with an API](https://sendhq.cc/guides/receive-email-with-api.md): Route inbound mail to your application, parse it safely, and make it useful in a product workflow.
- [Email Domain Verification: SPF, DKIM, and DMARC](https://sendhq.cc/guides/email-domain-verification.md): What domain verification is, why it matters, and how SPF, DKIM, and DMARC work together.
- [Improve Email Deliverability: Issues, Factors, and Monitoring](https://sendhq.cc/guides/email-deliverability.md): How to improve email deliverability: the factors that decide inbox placement, common deliverability problems, and how to monitor delivery rates.