Email API for AI agents to send, receive, and act on email, purpose-built for marketing and content workflows.
Equip your AI agents with real mailboxes, controlled outbound delivery, and live event monitoring for dynamic content and outreach.
Zekai Verdict
- What is it?
- Sendmux provides a unified API for AI agents to manage email communications, offering dedicated mailboxes and multi-provider sending capabilities.
- Best for
- AI Developers and Technical Founders building AI agents for marketing, customer support, and content automation.
- Not ideal for
- Requires significant development expertise to implement and manage.
- Price
- Free plan · paid from $7/team/mo
- Zekai Score
- 7.7/10
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See all 116 AI tools for Marketers →Sendmux is a global email API solution for AI agents, allowing developers anywhere to build email-enabled AI applications. For instance, a marketing agency in London could use Sendmux to create AI agents that manage email outreach campaigns, paying $7/team/mo for the Pro plan plus usage.
See Sendmux in action
Your workflow, automated
Before & After
AI agents struggle with complex email parsing and require stitching together multiple email services.
High LLM token usage for email processingAI agents communicate effectively with real mailboxes and structured email data.
96% token savings for email contentTry it with these prompts
Copy any prompt and paste it directly into the tool.
Use the Sendmux SDK to send an email. Specify the sender's email address, recipient's email address, subject, and the HTML or text body. Example: await sending.sendingSendEmail({ client: smx, body: { from: { email: "agen…
Use the Sendmux CLI to stream incoming messages. This command will output each incoming message as a JSON object. Example: sendmux mailbox:stream-events --follow
Integrate Sendmux tools into your AI agent using LangChain. This allows the agent to send emails, list messages, and reply. Example: const smx = new SendmuxToolkit({ apiKey: process.env.SENDMUX_API_KEY }); const agent = …
Prompts for Marketers
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Sendmux integrations
Best Sendmux alternatives
Sendmux vs. Custom Email Integration: Choose Sendmux if you need a specialized, unified API for AI agents that optimizes token usage and handles complex routing. Opt for a custom integration if your email needs are extremely basic, you have ample development resources, and token efficiency for LLMs is not a primary concern.
Is Sendmux worth it?
Why Marketing & Content Creation choose this tool
Key Use Cases
Sendmux offers a highly specialized solution for integrating email capabilities into AI agents, addressing a significant pain point for developers. Its ability to provide structured JSON from raw emails is a clear advantage for LLM-based agents, reducing token usage and improving processing efficiency. However, its technical nature means it requires development expertise, making it less accessible for non-technical marketing or content teams directly. The pricing model combines a subscription fee with usage-based costs, which can become complex to predict at scale.
Frequently asked questions
What is Sendmux?
How does Sendmux save LLM tokens?
Can I use my own email providers with Sendmux?
Is Sendmux suitable for multi-tenant applications?
Last reviewed:
Sendmux pricing and plans
Prices and features are updated regularly but can change at any time — always confirm on the official website. Some links on this page are affiliate links.
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Take it with you
- Why traditional email tools fail for AI agents
- The Sendmux advantage: Unified API & JSON parsing
- Understanding the API: Inbound vs. Outbound
- Connecting your first email provider (e.g., Gmail, SendGrid)
- Advanced Routing: Quotas, Weights, and Failover
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About Sendmux
Full Description
Sendmux provides a unified API for AI agents to manage email communications, offering dedicated mailboxes and multi-provider sending capabilities. It simplifies email integration for agents by handling inbound and outbound mail, routing, and real-time event processing without complex setups.
Editorial Verdict
Sendmux offers a highly specialized solution for integrating email capabilities into AI agents, addressing a significant pain point for developers. Its ability to provide structured JSON from raw emails is a clear advantage for LLM-based agents, reducing token usage and improving processing efficiency. However, its technical nature means it requires development expertise, making it less accessible for non-technical marketing or content teams directly. The pricing model combines a subscription fee with usage-based costs, which can become complex to predict at scale.
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