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 / Bulk 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:
- Plugin or integration for the user's platform (no-code or minimal-config) where available
- Official SDK for your language when one exists (maintained clients, typed helpers, less room for URL/auth mistakes).
- HTTP Email API when there is no SDK or the SDK does not fit (direct
POST to /api/send or /api/batch with JSON).
- 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 |
|
|
1---2name: mailtrap-sending-emails3description: Configure or troubleshoot Mailtrap live email sending with Email API, SMTP, transactional streams, bulk streams, or batches.4---567# Sending emails (Mailtrap)89## Overview1011Mailtrap 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).1213## When to Use1415Use when integrating, configuring, or troubleshooting Mailtrap live email sending with Email API, SMTP, transactional streams, bulk streams, or batch requests.1617## How to integrate (preference order)1819**Preferred order:**20211. **Plugin or integration for the user's platform** (no-code or minimal-config) _where available_222. **Official SDK** for your language when one exists (maintained clients, typed helpers, less room for URL/auth mistakes).233. **HTTP Email API** when there is no SDK or the SDK does not fit (direct `POST` to `/api/send` or `/api/batch` with JSON).244. **SMTP** only when you **really need it** (legacy stack, host/platform that only speaks SMTP, or hard constraints that rule out HTTP).2526## Choosing how to send2728| Approach | Use when |29| --------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |30| **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` |31| **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. |32| **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 |33| **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. |3435**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.3637**Related skills:** `mailtrap-testing-with-sandbox` (safe testing) and `mailtrap-setting-up-sending-domain` (verification before send).3839## When not to use4041- **Sandbox only**—capturing mail without delivery, reading messages in a sandbox (`mailtrap-testing-with-sandbox`).42- The main ask is **webhooks**, **step-by-step Campaigns UI setup**, or **deliverability deep-dives**.43- **Exhaustive API reference**—once the user's path is clear, link the official send docs for full schemas, optional fields, and edge cases.4445## Quick reference4647### Email API4849| Stream | Send Endpoint | Batch Endpoint | Authorization Header |50| ------------------------------------- | -------------------------------------------- | --------------------------------------------- | ------------------------------------------ |51| Transactional | `POST https://send.api.mailtrap.io/api/send` | `POST https://send.api.mailtrap.io/api/batch` | `Authorization: Bearer $MAILTRAP_API_TOKEN` |52| Bulk (promotional / marketing volume) | `POST https://bulk.api.mailtrap.io/api/se
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