Sendmux
Give AI agents real JSON inboxes.
At a glance
Free + paid · Source review 2026-11-02- Price & billing
Official pricing page reviewed 2026-11-02: Free plan $0 per team per month with 2 free mailboxes; Pro plan $7 per team per month plus usage, billed by accepted recipients and storage, with no per-seat or per-mailbox fees.
- Free allowance
Official pricing page reviewed 2026-11-02: Free plan $0 per team per month with 2 free mailboxes; Pro plan $7 per team per month plus usage, billed by accepted recipients and storage, with no per-seat or per-mailbox fees.
- Best suited to
AI agent developers who need email, calendar, and files through one API
Fit is editorial guidance, not a measured result.- Platforms
Access: not separately verified. Operating systems not separately verified.
Published-source facts and editorial guidance. No product test is implied. Confirm current conditions before purchase.
No product screenshot is claimed for this listing. Use the official website ↗ to inspect the current interface.
What to know before choosing
Good fit
AI agent developers who need email, calendar, and files through one API
Limits and trade-offs
Usage is metered by accepted recipients and storage, not seats or mailboxes; the Pro team fee is flat per team, and no authenticated product test was run.
Plans and free allowances
Official pricing page reviewed 2026-11-02: Free plan $0 per team per month with 2 free mailboxes; Pro plan $7 per team per month plus usage, billed by accepted recipients and storage, with no per-seat or per-mailbox fees.
Evidence
Official homepage ↗ (reviewed 2026-11-02), Official pricing page ↗ (reviewed 2026-11-02)
Official published page review; no authenticated product test
Dates: Last reviewed 2026-11-02. Last reviewed is the latest source or editorial review date; it is not a content-change date.
A closer look at Sendmux
Sendmux is the email API for AI agents, with inboxes, that lets agents send and receive email, manage calendars, and store files through one API. Agents get their own inbox, skills and an MCP endpoint teach the workflow, and a scoped API key grants access, with SDKs and CLI options for TypeScript, Python, LangChain, and OpenClaw, and pricing by usage rather than seats or mailboxes.
Editorial guidance based on published documentation. The workflow below is a suggested starting point, not a measured product result.
When to choose Sendmux
- AI agent developers who need a real inbox for agents
- Teams building agents that handle email and calendars
- Developers who prefer usage pricing over per-seat fees
When to choose something else
- Users who need a human email client rather than an agent API
- Teams that need flat unlimited email with no usage metering
A practical starting workflow
- Read the agent setup guide and get a Sendmux agent inbox
- Install the Sendmux skills or connect the hosted MCP endpoint
- Create a scoped API key in the dashboard for the agent
- Let the agent send and receive email and manage calendars through one API
- Scale usage as accepted recipients and storage grow, paying the Pro team fee when needed
Check before committing
- Vendor claims on the official page are not guarantees; actual results, quality and availability must be tested in the product.
- Prices and features may change after this review; recheck the official site before purchase or signup.
Common questions
What is Sendmux?
An email API for AI agents, with inboxes, that lets agents send and receive email, manage calendars, and store files through one API.
Is there a free plan?
Yes, the Free plan costs $0 per team per month, and the homepage notes 2 free mailboxes for agent setup.
How does Pro pricing work?
Pro costs $7 per team per month plus usage, billed by accepted recipients and storage, with no per-seat or per-mailbox fees.
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Sources and checks
Last source review is not a date of product testing. No rating or test result is implied by inclusion. Check the current plan and terms before buying.