---
title: Email API with Node.js | SendHQ
description: A server-side pattern for sending transactional email from Node.js without leaking API keys.
canonical: https://sendhq.cc/guides/email-api-nodejs
last-updated: 2026-08-24
---
# Email API with Node.js

A server-side pattern for sending transactional email from Node.js without leaking API keys.

Node.js applications should keep email sending behind a server-side module or job worker. The module receives a validated message request, calls the email API, and persists the provider response for observability.

## What this means in practice

- Server-only API credentials
- Input validation before sends
- Timeout and retry policy
- Stored message identifiers for support and audit

## Implementation checklist

1. Read the API key from a server environment variable.
2. Validate sender, recipient, subject, and content fields.
3. Call the email API from a service module or queue worker.
4. Store the returned message ID with the product event.
5. Retry only failures that are known to be transient.

## Questions teams ask

**Can I call an email API from browser JavaScript?**

Do not expose a sending API key in browser code. Send through your Node.js backend instead.

**Should email sending block a web request?**

For critical actions it can, but queues are often better for retries and resilience.

## 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.
- [Transactional Email API Guide](https://sendhq.cc/guides/transactional-email-api.md): A practical guide to sending passwords, receipts, alerts, and other product-triggered email reliably.
- [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.