Sendmux AI

Overview

Sendmux AI is a specialized email infrastructure platform designed specifically for AI agents. It bridges the gap between traditional email services and the requirements of autonomous agents by providing a unified API for sending, receiving, and routing emails. By stripping away unnecessary formatting and providing structured data, Sendmux allows AI agents to focus on processing content rather than parsing complex HTML.

Main Purpose and Target User Group

Main Purpose: To provide a robust, developer-friendly email API that enables AI agents to handle email communication efficiently, reliably, and at scale without being locked into a single provider.

Target User Group: AI agent developers, platform builders, SaaS companies managing email for customer agents, and engineering teams looking to integrate email capabilities into autonomous workflows.

Function Details and Operations

• Inbound Processing: Automatically converts raw emails into clean, structured JSON. It strips signatures, quoted history, and HTML noise, significantly reducing LLM token consumption.
• Outbound Sending: Supports "Bring Your Own Provider" (BYO) via SMTP or HTTP, allowing users to connect Gmail, SendGrid, Mailgun, Resend, or others. Includes a built-in sending account for immediate use.
• Intelligent Routing: Features weighted distribution and automatic failover. If a provider experiences downtime, traffic is rerouted instantly to ensure delivery.
• Quota Management: Granular control over sending limits with windows for second, minute, hour, and day intervals.
• Real-time Reactivity: Offers signed webhooks for delivery events and Server-Sent Events (SSE) for live mailbox monitoring, eliminating the need for inefficient polling loops.

User Benefits

• LLM Efficiency: Reduces token usage by up to 96% by delivering structured JSON instead of raw MIME/HTML.
• Provider Flexibility: Eliminates vendor lock-in; users can switch or combine multiple providers seamlessly.
• Operational Reliability: Automatic health monitoring and failover ensure high deliverability without manual intervention.
• Scalability: Designed for multi-tenancy, allowing platform builders to manage thousands of mailboxes across different teams with isolated data and quotas.
• Cost-Effective: Transparent, usage-based pricing with no per-seat or per-mailbox fees.

Compatibility and Integration

• API & SDKs: Comprehensive HTTP API, SDKs, and CLI tools for seamless integration into existing agent frameworks.
• MCP Support: Includes an Email Model Context Protocol (MCP) server for direct integration with AI-powered development environments.
• Provider Agnostic: Compatible with any SMTP-compliant email service provider.

Access and Activation Method

• Getting Started: Users can sign up at sendmux.ai to begin.
• Setup: Follow the documentation to create agent inboxes on custom domains or the provided @myagent.mx domain.
• Installation: Developers can install Sendmux skills via npx skills add Sendmux/skills if their agent supports skills, or utilize the provided SDKs and API documentation for custom implementations.

What is Sendmux AI?

Sendmux AI is an email automation platform specifically designed for AI agents. It provides a unified API to handle inbound and outbound email, routing, and delivery events, allowing developers to integrate email capabilities directly into their AI workflows without managing multiple fragmented services.

How does Sendmux help with email parsing for AI agents?

Standard email formats are often bloated with HTML and metadata that consume unnecessary LLM tokens. Sendmux optimizes this by stripping signatures, quoted history, and formatting, providing your AI agents with clean, structured JSON. This significantly reduces token usage and allows agents to focus on the actual content of the email.

Can I use my own SMTP or email provider with Sendmux?

Yes. Sendmux is built for flexibility, allowing you to connect your own providers (such as Gmail, SendGrid, Mailgun, or Postmark) via SMTP or OAuth. You can also use Sendmux’s built-in sending account if you prefer not to configure your own infrastructure.

Does Sendmux include inbound mailboxes?

Yes, Sendmux allows you to create dedicated inbound mailboxes on either your own custom domain or a shared @myagent.mx domain. These mailboxes are designed to be read by AI agents, providing structured data instead of raw email noise.

What are Sendmux webhooks and Server-Sent Events (SSE)?

These tools allow your application to react to email events in real-time without using inefficient polling loops. Webhooks provide notifications for delivery, receipt, and spam, while SSE allows for live updates to your mailbox clients as new messages arrive.

How does Sendmux pricing work?

Sendmux uses a transparent, usage-based billing model. There are no per-seat or per-mailbox fees. You pay $0.15 per 1,000 emails sent or received. Storage is billed at $0.02 per GB/month. You only pay for what you use, with no minimum commitments.

Does Sendmux have an MCP server or SDKs?

Yes, Sendmux provides a comprehensive developer toolkit, including an Email MCP (Model Context Protocol) server, official SDKs, and a CLI to help you integrate email functionality into your AI agents quickly and efficiently.