---
title: "Cold Email Sending Infrastructure | FirstSales"
description: "Connect unlimited mailboxes, rotate sending safely, and manage domains and tracking domains — scale cold email without burning sender reputation."
canonical: "https://firstsales.io/sending-infrastructure/"
---

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Sending Infrastructure

Sending Infrastructure · connect → rotate → scale, safely

# The sending layer that scales without burning reputation

FirstSales connects unlimited mailboxes, rotates every send across them, and manages your domains and tracking domains in one place. Smart throttling protects each inbox, so 87% lands in the primary inbox. Add capacity by adding mailboxes, not by paying a per-seat tax.

* Connect unlimited mailboxes, Google, Microsoft, or any SMTP/IMAP
* Automatic rotation spreads every send across your whole pool
* Smart throttling protects each inbox from volume spikes
* Domains and tracking domains managed in one dashboard

[Start your $1 trial](https://app.firstsales.io)[See Pricing](/pricing/)

$1 for 3 days · Cancel anytime · No per-mailbox fees

Trusted by founders & sales teams

app.firstsales.io

![FirstSales sending infrastructure dashboard, unlimited mailboxes connected with rotation and throttling](/_next/image/?url=%2Fimages%2Fsending-infrastructure%2Fhero.webp&w=3840&q=75)