SMTPing MCP server for AI agents and assistants

Securely connect your AI agents and chatbots (Claude, ChatGPT, Cursor, etc) with SMTPing MCP or direct API to verify email addresses, check threat lists, inspect account credits, and review usage through natural language.

SMTPing logoSMTPing
Api Key

SMTPing is an email verification service for validating addresses, checking threat lists, and monitoring account usage. It helps teams reduce bounced emails and protect sender reputation.

14 Tools

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Type what you want done — sign in and watch it run live in the Tool Router playground.

TOOL ROUTER PLAYGROUND
SMTPing
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TOOLS

Supported Tools

Every SMTPing action and event your agent gets out of the box.

Check Email

Check one email address against one selected SMTPing threat list and report whether it matched.

Check Email Batch

Synchronously check 1 to 1,000 email addresses against one selected SMTPing threat list and return all results.

Check Email Flags

Return all six SMTPing risk and domain flags for one email address in one request.

Create Bulk Check Job

Start an asynchronous SMTPing threat-list check for 1 to 100,000 email addresses.

Create Bulk Verification Job

Start asynchronous verification for 1 to 100,000 email addresses and return the job ID to use for status polling and result retrieval.

Export Usage

Download SMTPing usage history as a CSV file for the provider's default date range.

Get Bulk Check Job

Get progress and match counts for an asynchronous threat-list check job.

Get Bulk Check Results

Return all address-level matches for a bulk threat-list check job after its status is Succeeded or Completed.

Get Bulk Verification Job

Get progress and summary counts for an asynchronous bulk verification job.

Get Bulk Verification Results

Return all address-level results for a bulk verification job after its status is Succeeded.

Get Credits

Return the connected account's current credit balance, plan, and daily remaining credits.

Get Usage

Return aggregate request, email, credit, status, endpoint, and error usage for SMTPing's current default date range.

List Usage Requests

Return the newest available page of individual SMTPing API request history, up to the provider default of 50 rows, with page metadata.

Verify Email

Verify one email address and return its deliverability status and domain flags.

SETUP GUIDE

Connect SMTPing MCP Tool with your Agent

1

Install Composio

typescript
npm install @composio/core ai @ai-sdk/mcp @ai-sdk/openai
Install the Composio SDK and your agent framework
2

Create a session with MCP enabled

typescript
import { Composio } from "@composio/core";

const composio = new Composio();
const { mcp } = await composio.create("your-user-id", {
  toolkits: ["smtping"],
  mcp: true,
});
Create a session scoped to SMTPing and read its MCP URL and headers
3

Connect your agent to the MCP server

typescript
import { createMCPClient } from "@ai-sdk/mcp";
import { openai } from "@ai-sdk/openai";
import { generateText, stepCountIs } from "ai";

const client = await createMCPClient({
  transport: { type: "http", url: mcp.url, headers: mcp.headers },
});

const { text } = await generateText({
  model: openai("gpt-5.6-sol"),
  tools: await client.tools(),
  prompt: "Verify whether alice@example.com is deliverable and check it against threat lists",
  stopWhen: stepCountIs(10),
});

console.log(text);
await client.close();
Pass the session's MCP URL and headers to your agent and run a SMTPing request
SETUP GUIDE

Connect SMTPing API Tool with your Agent

1

Install Composio

typescript
npm install @composio/core @composio/openai openai
Install the Composio SDK, the OpenAI provider, and the OpenAI SDK
2

Create a Composio session

typescript
import OpenAI from "openai";
import { Composio } from "@composio/core";
import { OpenAIResponsesProvider } from "@composio/openai";

const composio = new Composio({ provider: new OpenAIResponsesProvider() });
const client = new OpenAI();

const session = await composio.create("your-user-id", { toolkits: ["smtping"] });
const tools = await session.tools();
Initialize Composio with the OpenAI Responses provider and create a session scoped to SMTPing
3

Run SMTPing tools with your agent

typescript
let response = await client.responses.create({
  model: "gpt-5.6-sol",
  tools,
  input: [{ role: "user", content: "Verify whether alice@example.com is deliverable and check it against threat lists" }],
});

while (response.output.some((o) => o.type === "function_call")) {
  const outputs = await composio.provider.handleToolCalls(session, response.output);
  response = await client.responses.create({
    model: "gpt-5.6-sol",
    tools,
    previous_response_id: response.id,
    input: outputs,
  });
}

console.log(response.output_text);
Send a request, execute the SMTPing tool calls through the session, and print the final answer

Why Use Composio?

AI Native SMTPing Integration

  • Supports both SMTPing MCP and direct API integrations
  • Structured, LLM-friendly schemas for reliable email verification and account checks
  • Rich coverage for validating addresses, checking threats, and querying SMTPing usage

Managed Auth

  • Securely connect your SMTPing API key without hard-coding it into agent prompts or application logic
  • Central place to manage, scope, and revoke SMTPing access
  • Per user and per environment credentials instead of shared keys

Agent Optimized Design

  • Tools are tuned using real error and success rates to improve reliability over time
  • Comprehensive execution logs so you always know what ran, when, and on whose behalf

Enterprise Grade Security

  • Fine-grained RBAC so you control which agents and users can access SMTPing
  • Scoped, least privilege access to SMTPing verification and account resources
  • Full audit trail of agent actions to support review and compliance

Rolling this out across your team?

Give your team centralized access control across every framework with Composio’s MCP Gateway.

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FAQ

Frequently asked questions

Yes, SMTPing requires you to configure your own API key. Once set up, Composio handles secure credential storage and API request handling for you.

Yes! Composio's Tool Router enables agents to use multiple toolkits. Learn more.

Yes. Composio is SOC 2 Type II compliant and is built to keep your SMTPing connection and credentials secure. OAuth tokens and API keys are encrypted, and sensitive customer data is protected at rest and in transit.

Composio also undergoes independent security testing and continuously monitors its systems for security threats. You can review the latest reports and policies in the Composio Trust Center.

Composio maintains and updates all toolkit integrations automatically, so your agents always work with the latest API versions.

Create the key in your SMTPing account settings, then paste it once on Composio's connection page. Composio stores it encrypted and uses it only for the SMTPing actions your agent runs. Nobody else in your workspace can read it, and you can revoke it inside SMTPing at any time.

When you connect a SMTPing account through Composio, every action runs under that account, so anything the agent creates, sends, or changes shows up in SMTPing as done by you. Keep an approval step in your prompt for actions with side effects, such as sending or deleting, and have the agent draft first.

Whatever the credentials you connect allow inside SMTPing. If SMTPing lets you scope a key to specific permissions, create a scoped one so the agent can only do what you intend. You can revoke the key inside SMTPing at any time.

Yes. Composio supports multiple connected accounts for the same app, and that works in Claude, ChatGPT, or any other assistant you connect through Composio. Give each SMTPing connection a name such as work or personal, and the assistant uses the one you mention in the request. Each account keeps its own credentials and nothing is merged.

The connection stops working the moment SMTPing rejects the old key. Create a new key in SMTPing and reconnect the account from the Composio dashboard or by asking your agent to reconnect SMTPing. Nothing else changes.

Composio's free Hobby plan includes 100,000 tool calls per month with no credit card, which covers most personal SMTPing use. Paid plans add higher limits and team features. Your SMTPing plan and its API limits still apply as usual.

Built-in connectors usually give one AI access to a limited set of apps. Many people use Composio because it lets their AI connect to more apps than it normally supports, or connect to multiple accounts for the same app (e.g. connect Claude to multiple SMTPing accounts).

With Composio, you connect SMTPing once and then use it across different AI assistants without setting it up separately in each one. Connect your apps to Composio once, then connect Composio to whichever AI you use, whether that's Claude, ChatGPT, Hermes, or your own custom assistant.

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