Best Alternatives to Aruba Email & Calendar

SenderKit

Runtime: npx

Build and send email, SMS, and push straight from your AI agent.

Mailbuttons

Runtime: npx

Governed email for AI agents: sandbox inboxes, server-side policy gate, tamper-evident audit.

Lumail

Runtime: npx

Official Lumail email marketing MCP for campaigns, subscribers, and workflows.

Slack MCP Server

Runtime: npx

MCP server providing Slack workspace data access with message history, threads, DMs, user info, and optional message posting.

Threadline MCP

Runtime: npx

Agent-to-agent messaging relay. Discover agents, send messages, and receive replies. Zero-config.

Line Bot MCP Server

Runtime: npx

Verified

Connects an AI agent to LINE Messaging API for messaging, user profiles, quotas, followers, and rich-menu management.

Emailmd

Runtime: npx

Convert markdown to email-safe HTML with linting and live preview via an MCP server or local CLI.

Webhook.site MCP Server

Runtime: uvx

Capture HTTP, email, and DNS callbacks with webhook.site from MCP clients.

Atomic Mail

Runtime: npx

Programmable email inbox for AI agents — JMAP, PoW auth, stdio MCP server.

Discord Node MCP

Runtime: npx

MCP server for controlling Discord servers via bot token

IMAP MCP Pro

Runtime: npx

Production IMAP & SMTP for Claude: multi-account email search, triage, send, and spam checks.

Domains + send/receive email + inbound webhooks + DNS for AI agents. One API, MCP, CLI.