SendMux
Give your AI agent a real inbox, not just an email wrapper.
At a glance
Starts at
Free to start
Price as published by the vendor, September 2026.
Free tier
Yes, limited
Platforms
Web, API
Best for
AI agents and chatbots that need inboxes.
Not for
Small businesses with custom SMTP needs
4.0 out of 5
Scored by a Toolio reviewer after real useOur verdict
SendMux provides actual inboxes for AI agents but can be limited with provider quotas. Great for those who need full control over emails, but might struggle without more complex setups.
✓What it does well
Actual InboxesAI agents get real email inboxes with all the features of a traditional inbox.
Flexible Usage PricingPricing scales based on actual usage of email and storage.
Granular Delivery ControlSupports weighted delivery, quotas, and failover mechanisms for reliability.
✕Where it falls short
Limited Provider FlexibilityStays within supported providers, no custom SMTP setup possible.
Complex SetupSetting up and managing multiple inboxes can be cumbersome without automation tools.
Fixed Daily Limits on Free PlanFree plan has a strict limit of 50 provider-accepted recipients per UTC day.
Key features
Email Sending ToolsAPI for sending emails with various customization options.
Inbox Management APIReceive and manage incoming email events through APIs without polling.
Flexible PricingPricing based on usage rather than fixed tiers, starting free with limited features.
Server-Sent Events APIStream incoming email events without the need for polling.