Free API
Free source (opens in a new tab)
Month
For: Prototyping agents
Limits
- 2 mailboxes, 1 domain
- $1 usage credit
1 more
- 50 recipients per day; managed sending 2 per hour
Includes
- Email API
- MCP endpoint
1 more
- No credit card
API included
Productivity & writing · pricing
Sendmux pricing in 2026: Free, Pro and Enterprise explained
Choose Sendmux if you build AI agents that need their own inboxes, calendars and files through one API, with usage billing and no per-seat or per-mailbox fees.
- Starting price
- From $7/mo (Pro)
- Free option
- Yes
- Plans
- 3
- Prices checked
- Sep 29, 2026
Sendmux plans and what they include
Sendmux combines a small team fee with usage. Free has no card requirement and includes 2 mailboxes, 1 domain, a $1 usage credit, the email API and an MCP endpoint, but sends 50 recipients per day, managed sending is limited to 2 per hour, and outgoing mail carries a Sendmux footer.
Pro is $7 per team per month plus usage, with prepaid usage and top-ups, no email footer and higher managed daily limits by review; resources are unlimited under fair usage. Enterprise is priced around your volume with dedicated infrastructure, priority support, custom SLAs and postpaid usage. Prices checked on 2026-09-29.
Sendmux plans compared
| Plan | Price | Billing | Who it is for | Key limits | API |
|---|---|---|---|---|---|
| Free API |
Free | Monthly | Prototyping agents | 2 mailboxes, 1 domain; $1 usage credit; 50 recipients per day; managed sending 2 per hour | Included |
| Pro API |
$7 per team per month plus usage | Monthly | Production agents | Unlimited* resources, fair usage applies | Included |
| Enterprise API |
Custom pricing | Unknown | High-volume senders | Priced around your volume | Included |
Which Sendmux plan to pick
| If you | Pick | Why |
|---|---|---|
| you are prototyping an agent that sends email | Free | 2 mailboxes, a $1 credit, the email API and MCP endpoint, with a footer on outgoing mail. |
| you send real mail and want no footer | Pro, $7 per team per month plus usage | No email footer, prepaid usage and higher managed daily limits by review. |
| you need postpaid billing and SLAs | Enterprise (custom) | Dedicated infrastructure, priority support, custom SLAs and postpaid usage. |
What is free, what costs extra
Free access and trial
Free plan, no credit card, with $1 usage credit.
None beyond Free.
Extra costs and taxes
Connected outbound $0.50 per 1,000, managed $0.75 per 1,000, inbound $0.50 per 1,000, storage $0.02 per GB-month.
Not stated.
Costs that are easy to miss
- Usage rates are connected outbound $0.50 per 1,000, managed $0.75 per 1,000, inbound $0.50 per 1,000 and storage $0.02 per GB-month.
- Unlimited resources on Pro are subject to fair usage and approval.
- Postpaid usage is Enterprise only, so Pro runs on prepaid top-ups.
- Taxes are not stated in our verified data.
Sendmux pricing and usage limits
Prices checked Sep 29, 2026 on the official US pricing page. Official pricing ↗ Prices and limits change often.
Free access and trial conditions
Free plan, no credit card, with $1 usage credit.
None beyond Free.
Paid plans: what changes as you upgrade
Pro API
$7 per team per month plus usage source (opens in a new tab)
Month
For: Production agents
Limits
- Unlimited* resources, fair usage applies
Includes
- Prepaid usage with top-ups
- No email footer
1 more
- Higher managed daily limits by review
API included
Enterprise API
Custom pricing source (opens in a new tab)
Unknown
For: High-volume senders
Limits
- Priced around your volume
Includes
- Dedicated infrastructure
- Priority support and custom SLAs
1 more
- Postpaid usage
API included
Usage caps, credits and extra costs
Connected outbound $0.50 per 1,000, managed $0.75 per 1,000, inbound $0.50 per 1,000, storage $0.02 per GB-month.
Not stated.
Sendmux FAQ
What does the Free plan include?
2 mailboxes, 1 domain, a $1 usage credit and 50 provider-accepted recipients a day; outgoing emails carry a Sendmux footer. source (opens in a new tab)
What does Pro cost?
$7 per team per month plus usage: $0.50 per 1,000 connected outbound, $0.75 per 1,000 managed, $0.50 per 1,000 inbound and $0.02 per GB-month storage. source (opens in a new tab)
Is usage billed in blocks?
No, billing counts each event, so 1,400 sent recipients bills as 1,400. source (opens in a new tab)
Is Sendmux free?
Yes. Free needs no card and includes a $1 usage credit and 2 mailboxes.
How much is Sendmux Pro?
$7 per team per month plus usage.
What does sending cost?
Connected outbound is $0.50 per 1,000 and managed is $0.75 per 1,000.
Does the free plan add a footer?
Yes. Outgoing emails on Free carry a Sendmux footer.
Is there a trial?
None beyond the Free plan.
More about Sendmux
- Full Sendmux guide: features, use cases, how-to and sources.
- Sendmux alternatives with their prices.
- Best productivity & writing tools compared by price.
- LLM API token cost calculator if you pay per token instead of per seat.