# How to integrate Smtp2go MCP with Mastra AI ```json { "title": "How to integrate Smtp2go MCP with Mastra AI", "toolkit": "Smtp2go", "toolkit_slug": "smtp2go", "framework": "Mastra AI", "framework_slug": "mastra-ai", "url": "https://composio.dev/toolkits/smtp2go/framework/mastra-ai", "markdown_url": "https://composio.dev/toolkits/smtp2go/framework/mastra-ai.md", "updated_at": "2026-05-06T08:29:13.142Z" } ``` ## Introduction This guide walks you through connecting Smtp2go to Mastra AI using the Composio tool router. By the end, you'll have a working Smtp2go agent that can search for bounced emails this week, add marketing@mydomain.com as allowed sender, list all verified sender domains through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Smtp2go account through Composio's Smtp2go MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Smtp2go with - [OpenAI Agents SDK](https://composio.dev/toolkits/smtp2go/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/smtp2go/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/smtp2go/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/smtp2go/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/smtp2go/framework/codex) - [OpenClaw](https://composio.dev/toolkits/smtp2go/framework/openclaw) - [Hermes](https://composio.dev/toolkits/smtp2go/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/smtp2go/framework/cli) - [Google ADK](https://composio.dev/toolkits/smtp2go/framework/google-adk) - [LangChain](https://composio.dev/toolkits/smtp2go/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/smtp2go/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/smtp2go/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/smtp2go/framework/crew-ai) ## TL;DR Here's what you'll learn: - Set up your environment so Mastra, OpenAI, and Composio work together - Create a Tool Router session in Composio that exposes Smtp2go tools - Connect Mastra's MCP client to the Composio generated MCP URL - Fetch Smtp2go tool definitions and attach them as a toolset - Build a Mastra agent that can reason, call tools, and return structured results - Run an interactive CLI where you can chat with your Smtp2go agent ## What is Mastra AI? Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP. Key features include: - MCP Client: Built-in support for Model Context Protocol servers - Toolsets: Organize tools into logical groups - Step Callbacks: Monitor and debug agent execution - OpenAI Integration: Works with OpenAI models via @ai-sdk/openai ## What is the Smtp2go MCP server, and what's possible with it? The Smtp2go MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Smtp2go account. It provides structured and secure access to your email sending and management infrastructure, so your agent can perform actions like searching email activity, managing allowed senders, updating sender domains, and controlling IP allow lists on your behalf. - Comprehensive email activity search: Ask your agent to filter and retrieve email events such as sends, opens, clicks, and bounces by recipient, date, or message ID. - Allowed sender management: Have your agent add, update, remove, or view allowed sender email addresses to control who can send emails from your account. - Sender domain configuration: Let the agent register new sender domains for SPF/DKIM verification and manage domain-related settings seamlessly. - IP allow list control: Direct your agent to add or remove IP addresses or CIDR ranges in your account’s IP allow list, enhancing security for sending sources. - Email delivery monitoring: Enable your agent to search and analyze sent emails, helping you monitor delivery, troubleshoot issues, and ensure reliable communication. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `SMTP2GO_ACTIVITY_SEARCH` | Search Email Activity | Tool to search activity events like sends, opens, clicks, and bounces. use when you need to filter account email activity by date, event, recipient, or message id. | | `SMTP2GO_ALLOWED_SENDERS_ADD` | Add Allowed Sender | Tool to add a new allowed sender email address. use when you need to whitelist a sender before sending email. example: add "user@example.com" to allowed senders list. | | `SMTP2GO_ALLOWED_SENDERS_REMOVE` | Remove Allowed Sender | Tool to remove a sender email address from the allowed senders list. use when you need to revoke send permissions for a validated address. | | `SMTP2GO_ALLOWED_SENDERS_UPDATE` | Update Allowed Sender | Tool to update details of an existing allowed sender. use after confirming the allowed sender id. | | `SMTP2GO_ALLOWED_SENDERS_VIEW` | View Allowed Senders | Tool to view the list of allowed senders configured in your account. use after setting up smtp2go authentication to retrieve your allowed-senders list. example: 'show me all verified allowed senders.' | | `SMTP2GO_DOMAIN_ADD` | Add Sender Domain | Tool to add a new sender domain for spf/dkim verification. use when you need to register a domain and optionally set tracking/return-path subdomains. | | `SMTP2GO_EMAIL_SEARCH` | Search SMTP2GO Emails | Tool to search sent emails. use when filtering your smtp2go account's email activity by criteria like date, sender, or recipient. call after authentication. | | `SMTP2GO_IP_ALLOW_LIST_ADD` | Add IP Allow List | Tool to add an ip address or cidr range to your account’s ip allow list. use when you need to whitelist specific sending sources by ip or cidr after confirming accuracy. | | `SMTP2GO_IP_ALLOW_LIST_REMOVE` | Remove IP from Allow List | Tool to remove an ip address from your account's ip allow list. use after identifying the ip you wish to revoke. | | `SMTP2GO_IP_ALLOW_LIST_VIEW` | View IP Allow List | Tool to view the list of ip addresses in your ip allow list. use after confirming your smtp2go api key is set. | | `SMTP2GO_SMS_VIEW_RECEIVED` | View Received SMS | Tool to retrieve received sms replies for your smtp2go account. use when you need to fetch incoming sms messages for analysis or display. pagination supported via limit and offset. | | `SMTP2GO_STATS_EMAIL_BOUNCES` | Get Email Bounces Stats | Tool to retrieve email bounces statistics. use after sending emails to analyze bounce metrics over a time period. | | `SMTP2GO_STATS_EMAIL_CYCLE` | Email Cycle Statistics | Tool to retrieve email cycle statistics. use when you need to analyze email delivery metrics over a specified date range. | | `SMTP2GO_STATS_EMAIL_HISTORY` | Email History Statistics | Tool to retrieve email history statistics. use when you need detailed delivery metrics within a date range. | | `SMTP2GO_STATS_EMAIL_SPAM` | Email Spam Statistics | Tool to retrieve email spam report statistics. use when analyzing spam trends for sent emails. | | `SMTP2GO_STATS_EMAIL_UNSUBS` | Email Unsubscription Stats | Tool to retrieve email unsubscribe statistics. use when you need unsubscribe data for your account over a date range. | | `SMTP2GO_SUBACCOUNTS_SEARCH` | Search Subaccounts | Tool to search subaccounts. use after authenticating to filter and paginate your subaccounts by name, email, or status. | | `SMTP2GO_SUBACCOUNTS_USAGE` | Subaccounts Usage | Tool to retrieve usage statistics for subaccounts. use when you need to monitor per-subaccount email usage. | | `SMTP2GO_SUPPRESSION_ADD` | Add to Suppression List | Tool to add email addresses or domains to the suppression list. use when you need to block sending emails to specific recipients or entire domains after unsubscribes or bounces. | | `SMTP2GO_SUPPRESSION_REMOVE` | Remove suppression entry | Tool to remove an email address or domain from the suppression list. use when you want to resume sending to the address or domain. | | `SMTP2GO_SUPPRESSION_VIEW` | View Suppression List | Tool to view the suppression list. use when you need to inspect suppressed email addresses in your account. | | `SMTP2GO_TEMPLATE_EDIT` | Edit Email Template | Tool to edit details of an existing email template. use when you need to update template properties after confirming its id. | | `SMTP2GO_TEMPLATE_SEARCH` | Search Email Templates | Tool to search your collection of email templates by id or name. use when you need to find templates matching specific criteria after authentication. | | `SMTP2GO_TEMPLATE_VIEW` | View Email Template | Tool to view details of a specific email template. use after you have the template id to inspect. | | `SMTP2GO_USERS_SMTP_ADD` | Add SMTP User | Tool to add a new smtp user. use when you need to provision a fresh smtp credential after collecting username and password. | | `SMTP2GO_USERS_SMTP_EDIT` | Edit SMTP User | Tool to edit details of an existing smtp user. use when you need to update username, password, sender restrictions, or enable/disable a user after confirming the target username. | | `SMTP2GO_USERS_SMTP_REMOVE` | Remove SMTP User | Tool to remove an smtp user from your account. use when you need to revoke smtp access for a user. | | `SMTP2GO_USERS_SMTP_VIEW` | View SMTP Users | Tool to list all smtp users configured on your account. use when you need to retrieve smtp user configurations. | | `SMTP2GO_WEBHOOK_ADD` | Add Webhook | Tool to create a new webhook. use when you need real-time notifications of email or sms events. | | `SMTP2GO_WEBHOOK_EDIT` | Edit Webhook | Tool to edit an existing webhook’s settings. use when you need to update a webhook's configuration after creation. | | `SMTP2GO_WEBHOOK_REMOVE` | Remove webhook | Tool to remove a webhook. use when you want to delete a webhook by its id from your smtp2go account. | | `SMTP2GO_WEBHOOK_VIEW` | View Webhooks | Tool to view all webhooks configured in your account. use when you need to inspect existing webhook configurations after setup. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Smtp2go MCP server is an implementation of the Model Context Protocol that connects your AI agent to Smtp2go. It provides structured and secure access so your agent can perform Smtp2go operations on your behalf through a secure, permission-based interface. With Composio's managed implementation, you don't have to create your own developer app. For production, if you're building an end product, we recommend using your own credentials. The managed server helps you prototype fast and go from 0-1 faster. ## Step-by-step Guide ### 1. Prerequisites Before starting, make sure you have: - Node.js 18 or higher - A Composio account with an active API key - An OpenAI API key - Basic familiarity with TypeScript ### 1. Getting API Keys for OpenAI and Composio OpenAI API Key - Go to the [OpenAI dashboard](https://platform.openai.com/settings/organization/api-keys) and create an API key. - You need credits or a connected billing setup to use the models. - Store the key somewhere safe. Composio API Key - Log in to the [Composio dashboard](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs). - Go to Settings and copy your API key. - This key lets your Mastra agent talk to Composio and reach Smtp2go through MCP. ### 2. Install dependencies Install the required packages. What's happening: - @composio/core is the Composio SDK for creating MCP sessions - @mastra/core provides the Agent class - @mastra/mcp is Mastra's MCP client - @ai-sdk/openai is the model wrapper for OpenAI - dotenv loads environment variables from .env ```bash npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv ``` ### 3. Set up environment variables Create a .env file in your project root. What's happening: - COMPOSIO_API_KEY authenticates your requests to Composio - COMPOSIO_USER_ID tells Composio which user this session belongs to - OPENAI_API_KEY lets the Mastra agent call OpenAI models ```bash COMPOSIO_API_KEY=your_composio_api_key_here COMPOSIO_USER_ID=your_user_id_here OPENAI_API_KEY=your_openai_api_key_here ``` ### 4. Import libraries and validate environment What's happening: - dotenv/config auto loads your .env so process.env.* is available - openai gives you a Mastra compatible model wrapper - Agent is the Mastra agent that will call tools and produce answers - MCPClient connects Mastra to your Composio MCP server - Composio is used to create a Tool Router session ```typescript import "dotenv/config"; import { openai } from "@ai-sdk/openai"; import { Agent } from "@mastra/core/agent"; import { MCPClient } from "@mastra/mcp"; import { Composio } from "@composio/core"; import * as readline from "readline"; import type { AiMessageType } from "@mastra/core/agent"; const openaiAPIKey = process.env.OPENAI_API_KEY; const composioAPIKey = process.env.COMPOSIO_API_KEY; const composioUserID = process.env.COMPOSIO_USER_ID; if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set"); if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set"); if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set"); const composio = new Composio({ apiKey: composioAPIKey as string, }); ``` ### 5. Create a Tool Router session for Smtp2go What's happening: - create spins up a short-lived MCP HTTP endpoint for this user - The toolkits array contains "smtp2go" for Smtp2go access - session.mcp.url is the MCP URL that Mastra's MCPClient will connect to ```typescript async function main() { const session = await composio.create( composioUserID as string, { toolkits: ["smtp2go"], }, ); const composioMCPUrl = session.mcp.url; console.log("Smtp2go MCP URL:", composioMCPUrl); ``` ### 6. Configure Mastra MCP client and fetch tools What's happening: - MCPClient takes an id for this client and a list of MCP servers - The headers property includes the x-api-key for authentication - getTools fetches the tool definitions exposed by the Smtp2go toolkit ```typescript const mcpClient = new MCPClient({ id: composioUserID as string, servers: { nasdaq: { url: new URL(composioMCPUrl), requestInit: { headers: session.mcp.headers, }, }, }, timeout: 30_000, }); console.log("Fetching MCP tools from Composio..."); const composioTools = await mcpClient.getTools(); console.log("Number of tools:", Object.keys(composioTools).length); ``` ### 7. Create the Mastra agent What's happening: - Agent is the core Mastra agent - name is just an identifier for logging and debugging - instructions guide the agent to use tools instead of only answering in natural language - model uses openai("gpt-5") to configure the underlying LLM ```typescript const agent = new Agent({ name: "smtp2go-mastra-agent", instructions: "You are an AI agent with Smtp2go tools via Composio.", model: "openai/gpt-5", }); ``` ### 8. Set up interactive chat interface What's happening: - messages keeps the full conversation history in Mastra's expected format - agent.generate runs the agent with conversation history and Smtp2go toolsets - maxSteps limits how many tool calls the agent can take in a single run - onStepFinish is a hook that prints intermediate steps for debugging ```typescript let messages: AiMessageType[] = []; console.log("Chat started! Type 'exit' or 'quit' to end.\n"); const rl = readline.createInterface({ input: process.stdin, output: process.stdout, prompt: "> ", }); rl.prompt(); rl.on("line", async (userInput: string) => { const trimmedInput = userInput.trim(); if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) { console.log("\nGoodbye!"); rl.close(); process.exit(0); } if (!trimmedInput) { rl.prompt(); return; } messages.push({ id: crypto.randomUUID(), role: "user", content: trimmedInput, }); console.log("\nAgent is thinking...\n"); try { const response = await agent.generate(messages, { toolsets: { smtp2go: composioTools, }, maxSteps: 8, }); const { text } = response; if (text && text.trim().length > 0) { console.log(`Agent: ${text}\n`); messages.push({ id: crypto.randomUUID(), role: "assistant", content: text, }); } } catch (error) { console.error("\nError:", error); } rl.prompt(); }); rl.on("close", async () => { console.log("\nSession ended."); await mcpClient.disconnect(); process.exit(0); }); } main().catch((err) => { console.error("Fatal error:", err); process.exit(1); }); ``` ## Complete Code ```typescript import "dotenv/config"; import { openai } from "@ai-sdk/openai"; import { Agent } from "@mastra/core/agent"; import { MCPClient } from "@mastra/mcp"; import { Composio } from "@composio/core"; import * as readline from "readline"; import type { AiMessageType } from "@mastra/core/agent"; const openaiAPIKey = process.env.OPENAI_API_KEY; const composioAPIKey = process.env.COMPOSIO_API_KEY; const composioUserID = process.env.COMPOSIO_USER_ID; if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set"); if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set"); if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set"); const composio = new Composio({ apiKey: composioAPIKey as string }); async function main() { const session = await composio.create(composioUserID as string, { toolkits: ["smtp2go"], }); const composioMCPUrl = session.mcp.url; const mcpClient = new MCPClient({ id: composioUserID as string, servers: { smtp2go: { url: new URL(composioMCPUrl), requestInit: { headers: session.mcp.headers, }, }, }, timeout: 30_000, }); const composioTools = await mcpClient.getTools(); const agent = new Agent({ name: "smtp2go-mastra-agent", instructions: "You are an AI agent with Smtp2go tools via Composio.", model: "openai/gpt-5", }); let messages: AiMessageType[] = []; const rl = readline.createInterface({ input: process.stdin, output: process.stdout, prompt: "> ", }); rl.prompt(); rl.on("line", async (input: string) => { const trimmed = input.trim(); if (["exit", "quit"].includes(trimmed.toLowerCase())) { rl.close(); return; } messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed }); const { text } = await agent.generate(messages, { toolsets: { smtp2go: composioTools }, maxSteps: 8, }); if (text) { console.log(`Agent: ${text}\n`); messages.push({ id: crypto.randomUUID(), role: "assistant", content: text }); } rl.prompt(); }); rl.on("close", async () => { await mcpClient.disconnect(); process.exit(0); }); } main(); ``` ## Conclusion You've built a Mastra AI agent that can interact with Smtp2go through Composio's Tool Router. You can extend this further by: - Adding other toolkits like Gmail, Slack, or GitHub - Building a web-based chat interface around this agent - Using multiple MCP endpoints to enable cross-app workflows ## How to build Smtp2go MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/smtp2go/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/smtp2go/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/smtp2go/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/smtp2go/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/smtp2go/framework/codex) - [OpenClaw](https://composio.dev/toolkits/smtp2go/framework/openclaw) - [Hermes](https://composio.dev/toolkits/smtp2go/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/smtp2go/framework/cli) - [Google ADK](https://composio.dev/toolkits/smtp2go/framework/google-adk) - [LangChain](https://composio.dev/toolkits/smtp2go/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/smtp2go/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/smtp2go/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/smtp2go/framework/crew-ai) ## Related Toolkits - [Apilio](https://composio.dev/toolkits/apilio) - Apilio is a home automation platform that lets you connect and control smart devices from different brands. It helps you build flexible automations with complex conditions, schedules, and integrations. - [Basin](https://composio.dev/toolkits/basin) - Basin is a no-code form backend for quickly setting up reliable contact forms. It lets you collect and manage form submissions without writing any server-side code. - [Bouncer](https://composio.dev/toolkits/bouncer) - Bouncer is an email validation platform that verifies the authenticity of email addresses in real-time and batch. It helps boost deliverability and reduce bounce rates for your communications. - [Conveyor](https://composio.dev/toolkits/conveyor) - Conveyor is a platform that automates security reviews with a Trust Center and AI-driven questionnaire automation. It streamlines compliance and vendor security processes for faster, hassle-free reviews. - [Crowdin](https://composio.dev/toolkits/crowdin) - Crowdin is a localization management platform that streamlines translation workflows and collaboration. It helps teams centralize multilingual content, boost productivity, and automate translation processes. - [Databox](https://composio.dev/toolkits/databox) - Databox is a business analytics platform that connects your data from any tool and device. It helps you track KPIs, build dashboards, and discover actionable insights. - [Detrack](https://composio.dev/toolkits/detrack) - Detrack is a delivery management platform for real-time tracking and proof of delivery. It helps businesses automate notifications and keep customers updated every step of the way. - [Dnsfilter](https://composio.dev/toolkits/dnsfilter) - Dnsfilter is a cloud-based DNS security and content filtering solution. It helps organizations block online threats and manage safe internet access with ease. - [Faraday](https://composio.dev/toolkits/faraday) - Faraday lets you embed AI in workflows across your stack for smarter automation. It boosts your favorite tools with actionable intelligence and seamless integration. - [Feathery](https://composio.dev/toolkits/feathery) - Feathery is an AI-powered platform for building dynamic data intake forms with advanced logic. It helps teams automate complex workflows and collect structured data with ease. - [Fillout forms](https://composio.dev/toolkits/fillout_forms) - Fillout forms is an online platform for building and managing forms with a flexible API. It lets you create, distribute, and collect responses from forms with ease. - [Formdesk](https://composio.dev/toolkits/formdesk) - Formdesk is an online form builder for creating and managing professional forms. It's perfect for collecting data, automating workflows, and integrating form submissions with your favorite services. - [Formsite](https://composio.dev/toolkits/formsite) - Formsite lets you build online forms and surveys with drag-and-drop simplicity. Capture, manage, and integrate form responses securely for streamlined workflows. - [Graphhopper](https://composio.dev/toolkits/graphhopper) - GraphHopper is an enterprise-grade Directions API for routing, optimization, and geocoding across multiple vehicle types. It enables fast, reliable route planning and logistics automation for businesses. - [Hyperbrowser](https://composio.dev/toolkits/hyperbrowser) - Hyperbrowser is a next-generation platform for scalable browser automation. It empowers AI agents to interact with web apps, automate workflows, and handle browser sessions at scale. - [La Growth Machine](https://composio.dev/toolkits/lagrowthmachine) - La Growth Machine automates multi-channel sales outreach and routine tasks for sales teams. Streamline your workflow and focus on closing more deals. - [Leverly](https://composio.dev/toolkits/leverly) - Leverly is a workflow automation platform that connects and coordinates actions across your apps. It streamlines repetitive processes so your business runs smoother, faster, and with fewer manual steps. - [Maintainx](https://composio.dev/toolkits/maintainx) - Maintainx is a cloud-based CMMS for centralizing maintenance data, communication, and workflows. It helps organizations streamline maintenance operations and improve team coordination. - [Make](https://composio.dev/toolkits/make) - Make is an automation platform that connects your favorite apps and services. Build powerful, custom workflows without writing code. - [Ntfy](https://composio.dev/toolkits/ntfy) - Ntfy is a notification service to send push messages to phones or desktops. Instantly deliver alerts and updates to users, devices, or teams. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Smtp2go MCP? With a standalone Smtp2go MCP server, the agents and LLMs can only access a fixed set of Smtp2go tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Smtp2go and many other apps based on the task at hand, all through a single MCP endpoint. ### Can I use Tool Router MCP with Mastra AI? Yes, you can. Mastra AI fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Smtp2go tools. ### Can I manage the permissions and scopes for Smtp2go while using Tool Router? Yes, absolutely. You can configure which Smtp2go scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do. ### How safe is my data with Composio Tool Router? All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Smtp2go data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)