IN THE FIELD GUIDE
sendmux
sendmux.ai
Sendmux is an email API designed for AI agents that provides real inboxes for sending and receiving emails through user-owned providers with automatic failover. It offers a unified API for outbound sending and inbound mailboxes, delivering clean JSON instead of raw HTML, and supports multi-tenant team environments with scoped API keys and usage-based billing.
THE PRODUCT, BEYOND THE PITCH
Automatically researched · Not editorially reviewed · Sources checked Sep 12, 2026
A good fit for
- Teams and developers building AI agents that require integrated email sending and receiving capabilities with flexible provider routing.
Know the limitations
- Free plan limits to two mailboxes and 50 accepted recipients daily across all outbound routes with fixed usage credit and no top-ups.
- Managed sending has fair usage and operational safety limits with higher daily limits available only by review on Pro plans.
What you can do
- Manage transactional and conversational email flows with provider failover and quota enforcement.
Features
- Create agent inboxes with real email addresses on real domains.
- Inbound mailboxes return parsed clean JSON with stripped signatures, quoted history, and tracking pixels to save LLM tokens.
- Outbound sending supports routing through multiple connected providers with weighted distribution and automatic failover on failure.
- Supports multiple access surfaces including REST, SSE, IMAP, SMTP, and signed webhooks for mailbox events.
- Automatic email thread grouping by Message-ID and References headers compliant with RFC 2822.
Integrations
Not confirmed yet.
Platforms & data export
Not confirmed yet.
THE COST FOR YOUR TEAM
Go beyond the starting price.
Published plan prices for your team size and usage. Results update as you type. Taxes, currency conversion and unlisted add-ons are excluded, and anything the source did not state is called out rather than guessed.
Known monthly subtotal
$0.00/month
1 of 1 tools could not be priced with these inputs, so this is not the full cost.
| Tool / plan | Monthly | Per year | What this assumes |
|---|---|---|---|
| No pricing recorded yet. Check the official site, or ask the owner to add it. | |||
Alternatives to explore
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