# Mailtrap Sending Emails

> Configure or troubleshoot Mailtrap live email sending with Email API, SMTP, transactional streams, bulk streams, or batches.

- Skill: `ranbot-ai/mailtrap-sending-emails` (Agent Skill)
- Install (CLI): `npx skillmds add ranbot-ai/mailtrap-sending-emails`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ranbot-ai/mailtrap-sending-emails/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: ranbot-ai (https://skillmd.com/u/ranbot-ai)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/ranbot-ai/mailtrap-sending-emails

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# Sending emails (Mailtrap)

## Overview

Mailtrap sends live email over **Email API** (REST) or **SMTP**. Two **streams** apply for API/SMTP: **Transactional** (non-promotional, app-generated) and **Bulk** (**promotional** / marketing volume). **Batch** is not a third stream: it is how you submit **many messages in one request** on whichever stream matches the content. **Campaigns** are a separate product path for promotional mail to **Mailtrap contacts**. Pair this sheet with the [Transactional](https://docs.mailtrap.io/developers/email-sending/transactional.md) / [Bulk](https://docs.mailtrap.io/developers/email-sending/bulk.md) developer pages when building or debugging integrations (including with AI-assisted coding).

## When to Use

Use when integrating, configuring, or troubleshooting Mailtrap live email sending with Email API, SMTP, transactional streams, bulk streams, or batch requests.

## How to integrate (preference order)

**Preferred order:**

1. **Plugin or integration for the user's platform** (no-code or minimal-config) _where available_
2. **Official SDK** for your language when one exists (maintained clients, typed helpers, less room for URL/auth mistakes).
3. **HTTP Email API** when there is no SDK or the SDK does not fit (direct `POST` to `/api/send` or `/api/batch` with JSON).
4. **SMTP** only when you **really need it** (legacy stack, host/platform that only speaks SMTP, or hard constraints that rule out HTTP).

## Choosing how to send

| Approach                          | Use when                                                                                                                                                                                                                                                                                                                  |
| --------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Transactional, single message** | Email **generated by your app** (password resets, receipts, notifications, alerts). One logical message per `POST https://send.api.mailtrap.io/api/send`                                                                                                                                                                  |
| **Bulk**                          | **Promotional** email **to contacts that you manage on your side** and send at volume through Mailtrap. Not the same as "batch": bulk is the **stream**, not the batch endpoint.                                                                                                                                          |
| **Batch**                         | You have **multiple different messages** to hand off **at the same time** (up to 500 per request). Cuts HTTP overhead; can be applied to both transactional and bulk                                                                                                                                                      |
| **Campaigns**                     | **Promotional** email to recipients stored as **Mailtrap contacts**, using Mailtrap **Campaigns** (audiences, scheduling, reporting in the product). **Recommended** to avoid implementing contact management and email sending logic; **requires UI setup** before sends flow—this skill does not replace that workflow. |

**Before generating SDK code:** read the README of the relevant SDK repository linked in the **SDKs** section below for current method signatures, constructor options, and examples. Do not rely on memory.

**Related skills:** `mailtrap-testing-with-sandbox` (safe testing) and `mailtrap-setting-up-sending-domain` (verification before send).

## When not to use

- **Sandbox only**—capturing mail without delivery, reading messages in a sandbox (`mailtrap-testing-with-sandbox`).
- The main ask is **webhooks**, **step-by-step Campaigns UI setup**, or **deliverability deep-dives**.
- **Exhaustive API reference**—once the user's path is clear, link the official send docs for full schemas, optional fields, and edge cases.

## Quick reference

### Email API

| Stream                                | Send Endpoint                                | Batch Endpoint                                | Authorization Header                       |
| ------------------------------------- | -------------------------------------------- | --------------------------------------------- | ------------------------------------------ |
| Transactional                         | `POST https://send.api.mailtrap.io/api/send` | `POST https://send.api.mailtrap.io/api/batch` | `Authorization: Bearer $MAILTRAP_API_TOKEN` |
| Bulk (promotional / marketing volume) | `POST https://bulk.api.mailtrap.io/api/se