Email for AI agents, set up by the agent.

# 1. Create a key and a sandbox identity. No domain, no DNS, no signup.
npx sendforai sandbox

# 2. Mint a connection token for plain HTTP and the hosted MCP server.
TOKEN=$(npx sendforai token | jq -r .token)

# 3. Send to the simulator. Nothing is delivered, nothing is billed.
curl https://api.sendforai.com/v1/emails \
  -H "Authorization: Bearer $TOKEN" \
  -H "content-type: application/json" \
  -d '{
    "from": "agent@<your sandbox identity>",
    "to": "delivered@simulator.sendforai.com",
    "subject": "Hello",
    "markdown": "It works."
  }'

The CLI prints JSON and never prompts, so an agent can run it unattended. When you have a domain, npx sendforai dns setup publishes the records with a Vercel or Cloudflare token. The token never leaves the agent's machine.

Install

Connect it to your agent

The hosted MCP server is at https://sendforai.com/mcp (Streamable HTTP). It authenticates with a connection token that you mint locally with npx sendforai token. Tokens last up to 90 days and nothing is stored server-side.

claude mcp add --transport http sendforai https://sendforai.com/mcp \
  --header "Authorization: Bearer <token>"

{
  "mcpServers": {
    "sendforai": {
      "url": "https://sendforai.com/mcp",
      "headers": { "Authorization": "Bearer <token>" }
    }
  }
}

{
  "servers": {
    "sendforai": {
      "type": "http",
      "url": "https://sendforai.com/mcp",
      "headers": { "Authorization": "Bearer <token>" }
    }
  }
}

{
  "mcpServers": {
    "sendforai": {
      "command": "npx",
      "args": ["-y", "@sendforai/mcp"],
      "env": {
        "SENDFORAI_DOMAIN": "example.com",
        "SENDFORAI_PRIVATE_KEY_FILE": "/path/to/private-key.pem"
      }
    }
  }
}

npx sendforai sandbox      # key + sandbox identity, no DNS
npx sendforai dns setup    # publish DNS with a Vercel or Cloudflare token
npx sendforai token        # mint a connection token (up to 90 days)

curl https://api.sendforai.com/v1/account \
  -H "Authorization: Bearer $TOKEN"

Human in the loop

What a human still has to do

Every human step is a place an agent stops and waits. Here are ours, next to what Resend's documentation said on November 12, 2026.

Resend column read on November 12, 2026 from resend.com/docs/ai-onboarding. "Not compared here" means that page didn't state it, so we left it out rather than guess. Resend is ahead in places: per resend.com/docs on the same date, it offers a hosted MCP server with OAuth, a CLI, agent skills and plugins, and receiving and inbox features that SendForAI does not have.

Responses

What your agent gets back

Every response carries its cost. dry_run plans a send without sending it, max_cost_usd refuses anything over a cap, and every error has a fix the agent can act on.

POST /v1/emails   { ..., "dry_run": true, "max_cost_usd": 0.01 }

{
  "id": null,
  "dry_run": true,
  "status": "planned",
  "recipients": [{ "to": "ana@example.com", "status": "accepted" }],
  "cost": {
    "emails": 1,
    "ses_usd": 0.0001,
    "billed_usd": 0,
    "included_remaining": 8799,
    "note": "Included in this sending month. 8799 of 10000 included emails remain this month."
  },
  "lint": [],
  "receipt": null
}

HTTP 409
{
  "error": {
    "code": "sandbox_identity",
    "message": "k3f9c….sandbox.sendforai.com is a sandbox identity, which can only send to addresses @simulator.sendforai.com.",
    "fix": "To send real email, add a domain you control to this account: publish TXT _sendforai.<your domain> ... With a Vercel or Cloudflare token, sfa.dns.setup({ domain }) (MCP: setup_dns, CLI: sendforai dns setup) does all of it.",
    "details": { "simulator": "delivered@simulator.sendforai.com" }
  }
}

Events are pullable, so the agent needs no webhook endpoint. Broadcasts wait for a human approval link. Spend comes from a prepaid balance with a monthly budget only a human can raise: $0 to build, $5 in months you send (10,000 emails included), then $0.11 per 1,000. Full pricing.

Limits

What SendForAI doesn't do

• No inbound email. It is send-only: no receiving and no inbox for your agent.
• One SDK. The SDK is for Node. Other languages use plain HTTP with a connection token.
• New domains warm up. A new sending domain starts with a daily cap that rises as it builds reputation.
• No OAuth on the hosted MCP server. It uses bearer tokens, so clients that only support OAuth connectors need the local server.
• Real mail needs a domain. A sandbox identity can only reach the simulator.
• Two things always need a person. Paying a top-up checkout link, and approving a broadcast.

Choosing between an inbox API and a sending API? Read what an AI agent needs from an email sending API, with the questions to ask any provider.

Machine readable

Endpoints your agent can read

Email for AI agents FAQ

Updated November 12, 2026. Spot an error? hello@sendforai.com.