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Email and SMS MCP servers compared

Most email and SMS platforms now ship an MCP server, so an AI agent can work in the account. They differ in what the agent may do: read data, draft content, or create and send campaigns. This guide compares the official servers.

Checked against each vendor's own documentation on October 21, 2026. Sequence is our product; its row is included for comparison.

MCP, the Model Context Protocol, is an open standard that lets an AI agent such as Claude, ChatGPT or Codex call tools in other software. For email and SMS, the question that matters is how far the agent can get on its own: can it only read reports, can it draft a campaign for you to finish, or can it build and send the whole thing?

At a glance

  • HubSpot
    Hosting
    Remote (mcp.hubspot.com)
    Status
    Generally available, April 2026
    Create and send
    Creates email drafts; sending not documented
    SMS
    No
  • Klaviyo
    Hosting
    Remote (mcp.klaviyo.com) or local
    Status
    Generally available, August 2025
    Create and send
    Yes: creates and sends campaigns, creates flows and templates
    SMS
    Configuration tools only
  • Mailchimp
    Hosting
    Claude and ChatGPT app; separate Transactional MCP
    Status
    Marketing app launched May 2026
    Create and send
    Marketing app drafts campaigns you launch in Mailchimp; Transactional MCP sends transactional email
    SMS
    No
  • Brevo
    Hosting
    Remote (mcp.brevo.com), split into sub-servers
    Status
    Not stated
    Create and send
    Email, SMS and WhatsApp campaign tools
    SMS
    Yes
  • ActiveCampaign
    Hosting
    Remote, per-account URL
    Status
    Not stated
    Create and send
    Contacts, lists, deals and automation enrollment; campaign sending described in the Help Center
    SMS
    Not documented
  • Resend
    Hosting
    Remote (mcp.resend.com) or local
    Status
    Remote server launched July 2026
    Create and send
    Yes: email, broadcasts, automations, contacts and domains
    SMS
    No (Resend is email only)
  • Twilio
    Hosting
    Local npm package (alpha); separate docs-only server
    Status
    Alpha
    Create and send
    Exposes Twilio's public APIs, including messaging
    SMS
    Through the raw messaging API
  • Customer.io
    Hosting
    Remote (mcp.customer.io), EU region available
    Status
    Not stated
    Create and send
    Yes, with a live-send scope an admin enables
    SMS
    Not documented
  • Sequence
    Hosting
    Remote
    Status
    Live
    Create and send
    Yes: builds and sends email and SMS sequences and broadcasts
    SMS
    Yes (US)

SendGrid had no official MCP server when we checked.

HubSpot MCP server

Hosting: Remote (mcp.hubspot.com). Sign-in: OAuth. Status: Generally available, April 2026.

What the agent can do: Creates email drafts; sending not documented.

  • Read and write tools for CRM records, segments, campaigns and marketing email drafts.
  • Some tools need Marketing Hub or a Pro or Enterprise tier.
  • Documented clients include Claude, ChatGPT and Gemini.

Sources: HubSpot developer docs, GA announcement

Klaviyo MCP server

Hosting: Remote (mcp.klaviyo.com) or local. Sign-in: OAuth (remote) or private API key (local). Status: Generally available, August 2025.

What the agent can do: Yes: creates and sends campaigns, creates flows and templates.

  • Has a read-only switch for cautious setups.
  • Documented clients include Claude, ChatGPT, Cursor and VS Code.

Sources: Klaviyo MCP server docs, Available tools

Mailchimp MCP server

Hosting: Claude and ChatGPT app; separate Transactional MCP. Sign-in: Transactional: API key. Status: Marketing app launched May 2026.

What the agent can do: Marketing app drafts campaigns you launch in Mailchimp; Transactional MCP sends transactional email.

  • The marketing app is a directory app inside Claude and ChatGPT, not a general MCP server.

Sources: Mailchimp announcement, Transactional MCP guide

Brevo MCP server

Hosting: Remote (mcp.brevo.com), split into sub-servers. Sign-in: MCP token created as an API key. Status: Not stated.

What the agent can do: Email, SMS and WhatsApp campaign tools.

  • The token grants full read and write access to the account.
  • Documented clients include Claude, Cursor, Windsurf and VS Code.

Sources: Brevo MCP docs

ActiveCampaign MCP server

Hosting: Remote, per-account URL. Sign-in: OAuth. Status: Not stated.

What the agent can do: Contacts, lists, deals and automation enrollment; campaign sending described in the Help Center.

  • Only account admins can connect Claude, and ActiveCampaign branding must be on.

Sources: ActiveCampaign Help Center

Resend MCP server

Hosting: Remote (mcp.resend.com) or local. Sign-in: OAuth or API key. Status: Remote server launched July 2026.

What the agent can do: Yes: email, broadcasts, automations, contacts and domains.

  • Covers the full Resend API.
  • Documented clients include Claude, Cursor, Codex and Copilot.

Sources: Resend MCP docs, Remote server changelog

Twilio MCP server

Hosting: Local npm package (alpha); separate docs-only server. Sign-in: Account SID with API key and secret. Status: Alpha.

What the agent can do: Exposes Twilio's public APIs, including messaging.

  • A general API bridge, not a marketing tool: no audiences, templates or sequences.

Sources: twilio-labs/mcp, Twilio docs MCP

Customer.io MCP server

Hosting: Remote (mcp.customer.io), EU region available. Sign-in: OAuth with scopes. Status: Not stated.

What the agent can do: Yes, with a live-send scope an admin enables.

  • Read access by default; editing live automations is restricted by default.

Sources: Customer.io MCP docs

Sequence MCP server

Hosting: remote, streamable HTTP. Sign-in: OAuth in claude.ai, ChatGPT and Codex, or an account key. Status: live.

Sequence is built for agents first. Its 102 tools cover the whole job: brands, sending domains, contacts, audiences, email and SMS templates, sequences, broadcasts, texting registration and reports. An agent can take a one-sentence request and leave a running email and text sequence behind it, while Sequence enforces the unsubscribe footer, SMS consent and quiet hours on every sequence and broadcast.

See the MCP server overview or the full tool reference.

How to choose

  • You already run a platform and want an assistant in it: use that vendor's server. HubSpot, Klaviyo and Customer.io give agents real write access to the account you have.
  • You want the agent to build and send, not draft: check that the server can create and send, not only draft. Mailchimp's marketing app drafts; Klaviyo, Resend and Sequence document sending email, and Brevo documents SMS and WhatsApp sends.
  • You need SMS in the same flow as email: Brevo's and Sequence's servers cover both channels. Twilio gives raw messaging only.
  • You want no builder at all: Sequence has no editor or workflow canvas; the agent does the setup and the platform does the sending.