How it works

Composio is an agent infrastructure platform that connects AI models to 1,000+ external tools through a single SDK and MCP endpoint. The Mailtrap toolkit inside Composio gives agents 49 pre-built actions spanning Email Sandbox inspection, template management, contact operations, sending domain configuration, and deliverability analytics. 

Connect your Mailtrap account once via API token, and every agent in your Composio workspace, whether running on OpenAI, Anthropic, LangChain, CrewAI, AutoGen, or any other supported framework, can call Mailtrap actions through natural language.

Configuration

Step 1: Create a Composio account at composio.dev (free tier: 20,000 tool calls/month)

Step 2: Get your Mailtrap API token from https://mailtrap.io/settings/api-tokens

Step 3: Connect Mailtrap in the Composio dashboard under Integrations → Mailtrap and enter your API token

Step 4: Install the SDK: npm install @composio/core (TypeScript) or pip install composio (Python)

Step 5: Initialize a session and retrieve tools:

import { Composio } from '@composio/core';

const composio = new Composio({ apiKey: process.env.COMPOSIO_API_KEY });
const session = await composio.create('your-user-id');
const tools = await session.tools(); // includes all 49 Mailtrap actions

Note: For MCP-based clients (Claude Desktop, Cursor, custom MCP agents), connect to session.mcp.url instead. All 49 Mailtrap actions appear automatically in your client without additional configuration.

For a detailed guide, consult the dedicated Composio Integration article.

Use cases

• After your agent sends a test email through Mailtrap SMTP, have it call MAILTRAP_LIST_MESSAGES and MAILTRAP_GET_MESSAGE_HTML_BODY to inspect the sandbox result and validate subject, rendering, and links — without opening the Mailtrap dashboard.
• Let an agent update your email templates directly from plain-language instructions: “Update the password-reset template to shorten the body copy and replace the footer logo” triggers MAILTRAP_UPDATE_EMAIL_TEMPLATE with the changes applied automatically.
• Run a daily deliverability check with a scheduled agent: it calls MAILTRAP_GET_SENDING_STATS_BY_DATE, compares bounce and open rates against your thresholds, and alerts your team via another Composio toolkit if something looks off.
• When a new user signs up, trigger an agent to call MAILTRAP_CREATE_CONTACT and assign them to the right list, with custom fields populated directly from your CRM data.

Supported functionalities

• Inspect Email Sandbox inboxes and retrieve full message content (HTML and plain text)
• Create, retrieve, update, and delete email templates
• Manage contacts, contact lists, and custom contact fields
• Import and export contacts in bulk
• Track delivery statistics by date, category, sending domain, and email service provider
• Configure and manage sending domains
• View email suppression lists (bounces, complaints, unsubscribes)
• Monitor account billing usage