Letterkeel: Send Email via SMTP, Resend, SendGrid & Mailgun

io.github.CyberMax-toolsPublished by GitHub account CyberMax-toolsv1.0.1Updated Oct 24, 2026

Letterkeel: send email from your own domain via SMTP, Resend, SendGrid, Mailgun, Postmark

VerifiedStreamable HTTPWeb executableCommunication & CollaborationBusiness & Commerce

Overview

AI-generated overview

Lets an assistant send email from your own domain through SMTP, Resend, SendGrid, Mailgun or Postmark.

What you can do
This server lets an assistant send email from your own domain through several delivery channels: SMTP, Resend, SendGrid, Mailgun and Postmark. It runs as a remote endpoint on Apify, which performs the actual send against the provider you choose.
When to use it
Use it when the assistant should send mail from your own domain and you already have sending credentials for SMTP, Resend, SendGrid, Mailgun or Postmark. If you only need drafts and never send, you do not need it.
Requirements
A remote endpoint connection with OAuth, and an Apify API token sent in the Authorization header as Bearer plus the token. You also need sending credentials for one of SMTP, Resend, SendGrid, Mailgun or Postmark.
Before you install
The Authorization header carries your Apify API token, a secret to keep private. Sending delivers real mail that cannot be recalled and may expose recipient data. Each accepted recipient is billed to your Apify account, so usage costs money.

Installation

In SourceWeft

  1. Open Letterkeel: Send Email via SMTP, Resend, SendGrid & Mailgun in the dashboard and add it to a workspace.
  2. Connect the required credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.CyberMax-tools%2Fsend-email/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.

{
  "mcpServers": {
    "letterkeel-send-email-via-smtp-resend-se": {
      "type": "http",
      "url": "https://mcp.apify.com/?tools=cybermax/send-email"
    }
  }
}

README

This repository has no README.

Tools

0
This server asks you to sign in, so SourceWeft could not read its tools without an account and has not indexed them. What a connected account sees can depend on that account and its permissions.

Version history

1
  1. v1.0.1LatestSep 26, 2026

Score

60% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts

    Declare a GitHub repository with a README, or serve resource_documentation in the OAuth protected-resource metadata.

  • License10 pts

    Declare a license in the repository or the registry entry.