Sim.ai Email Integration

How It Works

Sim.ai is an open-source canvas for building agent workflows visually, and MCP servers are its plug-in mechanism for external tools: configure a server once in workspace settings, and its tools become available to every Agent block. Dead Simple Email runs a hosted MCP server, so the whole integration is a form, not a codebase.

Honest framing: there is no dedicated Dead Simple Email block in Sim's toolbar as of August 2026. You don't need one — the MCP route below gives Agent blocks the full toolset, and a Function block can hit the REST API directly for fixed steps.

Connect the MCP Server (No Code)

1. Store your API key. In Sim, add an environment variable named DSE_API_KEY with your dse_... key so it never sits in plain text in the server config.
2. Add the server. Open your workspace settings, go to MCP Servers, and click Add Server (you need Write permission).
3. Fill in the connection:

# Sim workspace settings → MCP Servers → Add Server
Name:      deadsimple-email
Transport: Streamable HTTP
URL:       https://api.deadsimple.email/mcp

# Headers
Authorization: Bearer {{DSE_API_KEY}}

4. Test the connection. Click Test Connection before saving — Sim should report the server is reachable and discover 14 tools.
5. Attach tools to an Agent block. On your canvas, open an Agent block's tool picker and select the Dead Simple Email tools you want the agent to use. The agent then decides when to call them from conversation context.

Sim resolves {{DSE_API_KEY}} from your environment variables at request time, and each server card lists its tools with parameter names and types. If we add tools later, click Refresh on the server card to pull the latest schemas.

The 14 Tools Your Agent Blocks Get

A typical canvas: a trigger starts the workflow, an Agent block drafts and sends outreach with send_email, and a later Agent block checks the thread with read_thread and drafts the reply. Selecting only the tools each block needs keeps the agent's choices predictable.

Alternative: REST from a Function Block

For deterministic steps where you don't want an LLM choosing tools — "always send exactly this email" — call the REST API from a Function block instead:

// Sim resolves {{DSE_API_KEY}} from environment variables
const res = await fetch(
  "https://api.deadsimple.email/v1/inboxes/inb_your_inbox/messages",
  {
    method: "POST",
    headers: {
      Authorization: "Bearer {{DSE_API_KEY}}",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      to: ["user@example.com"],
      subject: "Your workflow finished",
      text_body: "All 3 steps completed successfully.",
    }),
  }
);
return await res.json();

The full REST surface — inbox CRUD, threads, webhooks, domains — is documented in the API reference.

Frequently Asked Questions