# How to integrate Neverbounce MCP with Mastra AI ```json { "title": "How to integrate Neverbounce MCP with Mastra AI", "toolkit": "Neverbounce", "toolkit_slug": "neverbounce", "framework": "Mastra AI", "framework_slug": "mastra-ai", "url": "https://composio.dev/toolkits/neverbounce/framework/mastra-ai", "markdown_url": "https://composio.dev/toolkits/neverbounce/framework/mastra-ai.md", "updated_at": "2026-05-12T10:20:05.703Z" } ``` ## Introduction This guide walks you through connecting Neverbounce to Mastra AI using the Composio tool router. By the end, you'll have a working Neverbounce agent that can verify a list of emails for bounces, download csv results from last bulk job, check your current neverbounce credit balance through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Neverbounce account through Composio's Neverbounce MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Neverbounce with - [OpenAI Agents SDK](https://composio.dev/toolkits/neverbounce/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/neverbounce/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/neverbounce/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/neverbounce/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/neverbounce/framework/codex) - [OpenClaw](https://composio.dev/toolkits/neverbounce/framework/openclaw) - [Hermes](https://composio.dev/toolkits/neverbounce/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/neverbounce/framework/cli) - [Google ADK](https://composio.dev/toolkits/neverbounce/framework/google-adk) - [LangChain](https://composio.dev/toolkits/neverbounce/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/neverbounce/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/neverbounce/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/neverbounce/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 Neverbounce tools - Connect Mastra's MCP client to the Composio generated MCP URL - Fetch Neverbounce 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 Neverbounce 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 Neverbounce MCP server, and what's possible with it? The Neverbounce MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Neverbounce account. It provides structured and secure access to your email verification tools, so your agent can perform actions like bulk verifying lists, checking job statuses, downloading results, and managing your account seamlessly. - Instant email verification and validation: Quickly verify email addresses for validity to reduce bounce rates and improve deliverability right from your agent. - Bulk email job management: Create, start, and track bulk verification jobs for entire email lists, letting your agent handle large-scale email hygiene automatically. - Automated job result retrieval: Download or fetch completed job results as CSVs or paginated data, making it easy to integrate verified emails into your workflows. - Account usage and credit tracking: Let your agent monitor account stats, credits, and usage so you always know your verification capacity and performance. - Secure job and data deletion: Direct your agent to permanently delete outdated or unnecessary jobs, ensuring your data remains clean and compliant. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `NEVERBOUNCE_ACCOUNT_INFO` | Get Account Info | Tool to get account information including credits, job counts, and usage statistics. Use when retrieving NeverBounce account summary after authentication. | | `NEVERBOUNCE_CONFIRM_POE` | Confirm Proof of Email | Tool to confirm proof of email ownership (POE) from the JavaScript widget. Use when verifying server-side that a user confirmed their email through the widget. | | `NEVERBOUNCE_JOBS_CREATE` | Create NeverBounce Bulk Verification Job | Tool to create a new bulk verification job with parsing, sampling, and callback options. Use for asynchronous list verification with advanced control. | | `NEVERBOUNCE_JOBS_DELETE` | Delete NeverBounce Job | Tool to permanently delete a job and its results. Use when you need to irreversibly remove a bulk verification job. This delete is irreversible. | | `NEVERBOUNCE_JOBS_DOWNLOAD_GET` | Download Job Results (GET) | Tool to download job results as a CSV file via GET. Use after job completion to retrieve segmented or enriched CSV output. | | `NEVERBOUNCE_JOBS_RESULTS` | Retrieve Job Results | Tool to retrieve paginated results for a completed job, including original data and verification outcomes. Use after confirming job completion; avoid aggressive polling as repeated calls before completion risk rate limit errors. | | `NEVERBOUNCE_JOBS_START` | Start NeverBounce Job | Tool to start a parsed job when auto_start is disabled. Use when you need to manually initiate a job that was created with auto_start=false. | | `NEVERBOUNCE_JOBS_STATUS` | Get bulk job status | Tool to get the status and progress of a bulk verification job. Use when | | `NEVERBOUNCE_PARSE_JOB` | Parse NeverBounce Job | Tool to parse a job created with auto_parse disabled. Use when you need to manually parse a job. Cannot reparse once parsed. | | `NEVERBOUNCE_SEARCH_JOBS` | Search bulk verification jobs | Tool to search and list bulk verification jobs in your account with pagination and filtering. Use when retrieving jobs by id, filename, or status, or when listing all jobs with pagination. | | `NEVERBOUNCE_SINGLE_CHECK` | NeverBounce Single Check | Tool to verify a single email address and gather additional information. Use when you need real-time validation at the point of entry. | | `NEVERBOUNCE_WIDGET_SEND_EVENT` | JS Widget Send Event | Tool to send widget form events via the JS widget API. Use when reporting form.load or form.completion events after user interactions with your form. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Neverbounce MCP server is an implementation of the Model Context Protocol that connects your AI agent to Neverbounce. It provides structured and secure access so your agent can perform Neverbounce 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 Neverbounce 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 Neverbounce What's happening: - create spins up a short-lived MCP HTTP endpoint for this user - The toolkits array contains "neverbounce" for Neverbounce 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: ["neverbounce"], }, ); const composioMCPUrl = session.mcp.url; console.log("Neverbounce 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 Neverbounce 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: "neverbounce-mastra-agent", instructions: "You are an AI agent with Neverbounce 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 Neverbounce 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: { neverbounce: 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: ["neverbounce"], }); const composioMCPUrl = session.mcp.url; const mcpClient = new MCPClient({ id: composioUserID as string, servers: { neverbounce: { url: new URL(composioMCPUrl), requestInit: { headers: session.mcp.headers, }, }, }, timeout: 30_000, }); const composioTools = await mcpClient.getTools(); const agent = new Agent({ name: "neverbounce-mastra-agent", instructions: "You are an AI agent with Neverbounce 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: { neverbounce: 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 Neverbounce 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 Neverbounce MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/neverbounce/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/neverbounce/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/neverbounce/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/neverbounce/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/neverbounce/framework/codex) - [OpenClaw](https://composio.dev/toolkits/neverbounce/framework/openclaw) - [Hermes](https://composio.dev/toolkits/neverbounce/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/neverbounce/framework/cli) - [Google ADK](https://composio.dev/toolkits/neverbounce/framework/google-adk) - [LangChain](https://composio.dev/toolkits/neverbounce/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/neverbounce/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/neverbounce/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/neverbounce/framework/crew-ai) ## Related Toolkits - [Reddit](https://composio.dev/toolkits/reddit) - Reddit is a social news platform with thriving user-driven communities (subreddits). It's the go-to place for discussion, content sharing, and viral marketing. - [Facebook](https://composio.dev/toolkits/facebook) - Facebook is a social media and advertising platform for businesses and creators. It helps you connect, share, and manage content across your public Facebook Pages. - [Linkedin](https://composio.dev/toolkits/linkedin) - LinkedIn is a professional networking platform for connecting, sharing content, and engaging with business opportunities. It's the go-to place for building your professional brand and unlocking new career connections. - [Active campaign](https://composio.dev/toolkits/active_campaign) - ActiveCampaign is a marketing automation and CRM platform for managing email campaigns, sales pipelines, and customer segmentation. It helps businesses engage customers and drive growth through smart automation and targeted outreach. - [ActiveTrail](https://composio.dev/toolkits/active_trail) - ActiveTrail is a user-friendly email marketing and automation platform. It helps you reach subscribers and automate campaigns with ease. - [Ahrefs](https://composio.dev/toolkits/ahrefs) - Ahrefs is an SEO and marketing platform for site audits, keyword research, and competitor insights. It helps you improve search rankings and drive organic traffic. - [Amcards](https://composio.dev/toolkits/amcards) - AMCards lets you create and mail personalized greeting cards online. Build stronger customer relationships with easy, automated card campaigns. - [Beamer](https://composio.dev/toolkits/beamer) - Beamer is a news and changelog platform for in-app announcements and feature updates. It helps companies boost user engagement by sharing news where users are most active. - [Benchmark email](https://composio.dev/toolkits/benchmark_email) - Benchmark Email is a platform for creating, sending, and tracking email campaigns. It's built to help you engage audiences and analyze results—all in one place. - [Bigmailer](https://composio.dev/toolkits/bigmailer) - BigMailer is an email marketing platform for managing multiple brands with white-labeling and automation. It helps teams streamline campaigns and simplify integration with Amazon SES. - [Brandfetch](https://composio.dev/toolkits/brandfetch) - Brandfetch is an API that delivers company logos, colors, and visual branding assets. It helps marketers and developers keep brand visuals consistent everywhere. - [Brevo](https://composio.dev/toolkits/brevo) - Brevo is an all-in-one email and SMS marketing platform for transactional messaging, automation, and CRM. It helps businesses engage customers and streamline communications through powerful campaign tools. - [Campayn](https://composio.dev/toolkits/campayn) - Campayn is an email marketing platform for creating, sending, and managing campaigns. It helps businesses engage contacts and grow audiences with easy-to-use tools. - [Cardly](https://composio.dev/toolkits/cardly) - Cardly is a platform for creating and sending personalized direct mail to customers. It helps businesses break through the digital clutter by getting real engagement via physical mailboxes. - [ClickSend](https://composio.dev/toolkits/clicksend) - ClickSend is a cloud-based SMS and email marketing platform for businesses. It streamlines communication by enabling quick message delivery and contact management. - [Crustdata](https://composio.dev/toolkits/crustdata) - CrustData is an AI-powered data intelligence platform for real-time company and people data. It helps B2B sales teams, AI SDRs, and investors react to live business signals. - [Curated](https://composio.dev/toolkits/curated) - Curated is a platform for collecting, curating, and publishing newsletters. It streamlines content aggregation and distribution for creators and teams. - [Customerio](https://composio.dev/toolkits/customerio) - Customer.io is a customer engagement platform for targeted messaging across email, SMS, and push. Easily automate, segment, and track communications with your audience. - [Cutt ly](https://composio.dev/toolkits/cutt_ly) - Cutt.ly is a URL shortening service for managing and analyzing links. Streamline your workflows with quick, trackable, and branded short URLs. - [Demio](https://composio.dev/toolkits/demio) - Demio is webinar software built for marketers, offering both live and automated sessions with interactive features. It helps teams engage audiences and optimize lead generation through detailed analytics. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Neverbounce MCP? With a standalone Neverbounce MCP server, the agents and LLMs can only access a fixed set of Neverbounce tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Neverbounce 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 Neverbounce tools. ### Can I manage the permissions and scopes for Neverbounce while using Tool Router? Yes, absolutely. You can configure which Neverbounce 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 Neverbounce data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)