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How to integrate SMTPing MCP with Hermes

Connect Hermes to SMTPing MCP. Verify an email address before sending, check an address against threat lists, and more using natural language, with authentication handled for you.

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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

Introduction

Hermes is a 24/7 autonomous agent that lives on your computer or server — it remembers what it learns and evolves as your usage grows.

This guide explains the easiest and most robust way to connect your SMTPing account to Hermes. You can do this through either Composio Connect CLI or Composio Connect MCP. For personal use we recommend the CLI, but you won't go wrong with MCP either.

Also integrate SMTPing with

ChatGPTClaude CoworkAtomic Agent

What is Composio Connect?

Composio Connect is a consumer offering that lets anyone plug 1,500+ applications directly into their agent harness — including Hermes. It can:

  • Search and load tools from relevant toolkits on-demand, reducing context usage.
  • Chain multiple tools to accomplish complex workflows via a remote workbench, without excessive back-and-forth with the LLM.
  • Manage app authentication end-to-end with zero manual overhead.

Integrating SMTPing with Hermes

Using Composio Connect CLI

1. Install the Composio CLI

Run the install script directly, or paste https://composio.dev/hermes into your Hermes chat box to have it installed for you.

bash
curl -fsSL https://composio.dev/install | bash
Hermes authenticating with Composio

2. Authenticate

Once the CLI is installed, ask Hermes to authenticate with Composio.

3. Connect to SMTPing

Ask your agent to connect to SMTPing, or simply request any SMTPing-related task. Hermes will prompt you to authenticate and authorize access.

4. Done. You're all set with a new SMTPing connection.

Using Composio Connect MCP

1. Get your MCP URL and API Key

Go to dashboard.composio.dev and copy your Connect MCP URL and API key.

Copy MCP URL and API key from Composio dashboard

2. Open the Hermes config file

bash
nano ~/.hermes/config.yaml

3. Add the Composio Connect MCP server

bash
mcp_servers:
  composio:
    url: "https://connect.composio.dev/mcp"
    headers:
      x-consumer-api-key: "YOUR_COMPOSIO_API_KEY"
    connect_timeout: 60
    timeout: 180

Save with Ctrl + O, Enter, then exit with Ctrl + X.

4. Restart your Hermes agent

Once restarted, ask your agent to connect to SMTPing or request any SMTPing-related task. It will prompt you to authenticate and authorize access.

5. Done!

What is the SMTPing MCP server, and what's possible with it?

The SMTPing MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your SMTPing account. It provides structured and secure access to email verification, threat-list checks, bulk jobs, credits, and usage data, so your agent can verify addresses, identify risky emails, process large lists, monitor credits, and review API usage on your behalf.

  • Email address verification: Have your agent verify individual email addresses and review their deliverability status and domain flags.
  • Threat-list screening: Direct your agent to check an email or a batch of up to 1,000 addresses against a selected SMTPing threat list.
  • Bulk email processing: Instruct your agent to start large verification or threat-list jobs for up to 100,000 addresses, then check progress and retrieve the results.
  • Risk and domain flag checks: Let the agent inspect all six SMTPing risk and domain flags for a specific email address.
  • Credits and usage tracking: Have your agent check remaining credits, review aggregate usage, list recent API requests, or export usage history as a CSV file.

Way Forward

With SMTPing connected, Hermes can now act on your behalf whenever it detects a relevant task or you ask it to.

From here, you can extend Hermes further:

  • Connect more apps: Calendar, Slack, Notion, Linear, and hundreds of others are available through the same Composio Connect setup. Each new integration compounds what Hermes can do for you.
  • Build workflows across tools: Once multiple apps are connected, Hermes can chain actions together — turn an email into a calendar invite, a Slack message into a Linear ticket, or a meeting note into a follow-up draft.
  • Let it learn your patterns: The more you use Hermes, the better it gets at anticipating how you'd handle recurring tasks. Give it feedback on drafts and decisions, and it will adapt.

If you run into trouble or want to share what you've built, join the community or check out the Docs for deeper configuration options.

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.

FRAMEWORKS

How to build SMTPing MCP Agent with another framework

ChatGPT logo

ChatGPT

Use SMTPing MCP with ChatGPT

Claude Cowork logo

Claude Cowork

Use SMTPing MCP with Claude Cowork

Atomic Agent logo

Atomic Agent

Use SMTPing MCP with Atomic Agent

FAQ

Frequently asked questions

With a standalone SMTPing MCP server, the agents and LLMs can only access a fixed set of SMTPing tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from SMTPing and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Hermes 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 SMTPing tools.

Yes, absolutely. You can configure which SMTPing 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.

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 SMTPing data and credentials are handled as safely as possible.

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