# sending.ac

> Cold email infrastructure that fixes itself, before anyone notices. Isolated, pre-warmed mailboxes with deliverability monitoring built in, so a burning domain reaches you before it reaches your client.

sending.ac provisions and runs the sending infrastructure underneath cold email: domains, DNS and mailboxes on Microsoft Azure or Google Workspace, each tenant on its own IPs and reputation. It is not a sequencer. It connects to the sequencer you already run.

What it does:

- Provisions domains and DNS (SPF, DKIM, DMARC) automatically, per domain, verified before the first send.
- Measures inbox placement from inside real inboxes, hourly, across every major provider, rather than inferring it from bounces after the fact.
- Flags a burning mailbox from sending data alone, days before the reply rate would show it. That signal is called Risk Level and is proprietary.
- Verifies warm-up from outside the tool doing the warming, including on mailboxes bought elsewhere.
- Runs seven deliverability checks a day, 28 days deep, and states what broke, why it broke, and what to do about it.
- Gives every tenant its own IPs and reputation, never pooled with a stranger's complaint rate.
- Connects natively to Instantly, Smartlead, PlusVibe and EmailBison. Mailboxes bought anywhere can be connected free.
- Exposes a full REST API and an MCP server, so an agent such as Claude, ChatGPT or Cursor can provision infrastructure and monitor deliverability from a natural-language prompt.

Scale: 6M+ domains with deliverability data on file, 200K+ mailboxes under management, and 5M+ emails processed every 24 hours. Research from sending.ac helped Instantly.ai improve its warm-up pool in 2024.

Pricing is the same on either provider; what changes is the inbox allowance. Starter is $99/mo for 150 Azure inboxes ($0.65 each after) or 25 Google inboxes ($3.50 each after). Growth is $199/mo for 350 Azure inboxes ($0.55 each after) or 60 Google inboxes ($3.30 each after). Agency is $499/mo for 1,000 Azure inboxes ($0.50 each after) or 160 Google inboxes ($3.10 each after). Up to 75 inboxes sit on one domain on Azure, 10 on Google. Billing is monthly, quarterly or yearly, and yearly includes two months free.

Who it is for: agencies running cold email for several clients, who need each client walled off from the others; in-house teams sending 1,000+ a day who lose time guessing why replies dropped; and builders provisioning outbound infrastructure programmatically through an agent.

What customers say:

- "I tested sending a link and a GIF in the very first email of a sequence, normally a fast way to get flagged. Still landed in primary." Saief Tissaoui, customer.
- "Can confirm. We actually tested them, and performed next to Winnr the best." David Lehnert, founder of Wyngman.
- "You guys have the smoothest UX/UI of all the inbox resellers I have purchased from. And I have worked with ALL of them." Sergio Perea, customer.

sending.ac does not run sales calls. Booking a call reaches the founder or a deliverability advisor directly.

## Product

- [Landing page](https://sending.ac/): what it does, proof, sequencer integrations, agent access, platform detail, pricing and FAQ.
- [Pricing](https://sending.ac/pricing.md): plans, inbox allowances and per-inbox rates for Azure and Google, in plain markdown.
- [Book a call](https://sending.ac/#book): reaches the founder or a deliverability advisor.

## Developers

- [MCP server](https://builders.ac): provision and monitor infrastructure from Claude, ChatGPT or Cursor, including sandbox credentials.
- [API docs](https://docs.builders.ac): REST reference for domains, mailboxes, placement and risk.

## Optional

- [Privacy](https://sending.ac/privacy): privacy policy.
- [Terms](https://sending.ac/terms): terms of service.
- [Contact](https://sending.ac/contact): general enquiries.
- [Affiliates](https://sending.ac/affiliates): affiliate programme.