AINave
Artificial Intelligence
Visit website

Sendmux

Email inbox API for AI agents

FreemiumArtificial IntelligenceListed Jul 18, 2026

About Sendmux

Sendmux is an email inbox API for AI agents that lets developers give agents real mailboxes, controlled outbound sending, live inbox events, and developer tools in one platform. Instead of stitching together a sending API, mailbox provider, parser, webhook service, and separate billing system, teams can use Sendmux as the email API layer for agents that need to send, receive, route, and react to email in production.

What Sendmux does

AINave analysis

Lets developers give AI agents mailboxes and use them to send, receive, route and react to email through an API.

Best for
Developers building AI agentsPlatform builders running email for customers' agentsTeams operating support or outreach agents
Use it to
  • Giving an AI agent a dedicated inbox
  • Sending transactional or reply email from agent code
  • Receiving and triaging inbound email with agents
  • Routing outbound sending across multiple providers
  • Streaming mailbox events to trigger agent actions

Based on Sendmux's listing and website.

Featured on AINave badge

Show you're on AINave

Add the badge to Sendmux's site. It links back to this page.

Alternatives to Sendmux

See all 3 alternatives
  1. 1
    Mails.ai
    Same job

    Automate cold email outreach with AI-driven marketing

    Claim this listing

    Pick it if you want a closely comparable agent inbox with prompt-injection quarantine flags, scheduled sends and drafts, per-agent reputation scores, and a free tier.

    • Free plan
    • API
    • Web
    • CLI
    Drop-in replacementFreemiumSimilar price to Sendmux
    View Mails.ai
  2. 2
    Mailyond

    One email inbox for all your domains

    Pick it if you run several products or domains and want to reply as each brand from one inbox, with a hosted MCP server for an assistant to read and answer mail.

    • API
    • Web
    Covers some of itPaidCosts more than SendmuxView Mailyond
  3. 3
    Transmit

    email infra, byok sending, transactional emails

    Pick it if your main need is marketing campaigns, domain warmup, or sending through your own AWS SES account, rather than giving agents their own mailboxes.

    • Free plan
    • API
    • Web
    Covers some of itFreeCosts more than SendmuxView Transmit