Domain warmup gets your sending domains ready. Inbox allocation is what happens next. It is the process of deciding how many inboxes to set up, which campaigns they are assigned to, and how volume is distributed across them.
Get this wrong and you either burn through your sending capacity too quickly or run campaigns at a volume so low they take months to generate meaningful results.
Why you need more than one inbox
Every inbox has a safe daily sending limit. Push beyond it and email providers start treating your sends as suspicious. Stay within it and your deliverability stays clean.
For most cold outreach, that limit sits somewhere between 30 and 50 emails per inbox per day. If you want to send 500 emails a day across a campaign, you need at least 10 to 15 inboxes running in parallel.
This is why inbox allocation matters. It determines how much volume your infrastructure can support without creating deliverability risk.
How we set up your inboxes
We configure inboxes across your sending domains before any campaign goes live. Here is how we approach it.
We match inbox count to campaign volume. We calculate how many inboxes are needed based on the target send volume for your campaigns and build the infrastructure to support it. We always add a small buffer so you are never running at the absolute limit.
We separate inboxes by campaign and ICP. Different campaigns run from different inboxes. This means that if one campaign runs into a deliverability issue it does not affect the others. Each ICP segment and each outreach angle has its own sending lane.
We use custom sending domains for each inbox. Every inbox sits on a dedicated sending domain rather than your primary company domain. This protects your main brand reputation regardless of what happens in your outbound campaigns.
We configure each inbox with correct authentication. SPF, DKIM, and DMARC are set correctly on every inbox before it sends anything. These are the technical signals that email providers check to verify your emails are legitimate. Missing or misconfigured authentication is one of the most common causes of inbox placement problems.
How volume gets distributed
We do not send everything from one inbox at the same time. Volume gets distributed across your inbox pool throughout the day following a natural sending pattern.
Sending 500 emails in a two-hour window from a single inbox looks like automated bulk sending to most email providers. Spreading 500 emails across 15 inboxes over an eight-hour window looks like a normal working day of sales activity.
The distribution logic is built into how we configure your sequencing tools. You do not need to manage it manually.
What changes as you scale
As your campaign volume grows, the inbox infrastructure scales with it. Adding more contacts to a campaign, launching additional ICP segments, or running campaigns in parallel all require additional inboxes and domains.
We review infrastructure capacity as part of the quarterly scaling roadmap. If the current setup is approaching its limits we flag it and expand the infrastructure before performance is affected.
FAQ
How many inboxes do we get on each plan?
The number of inboxes is determined by your plan tier. Starter includes 24 inboxes across 12 domains. Pro includes 40 inboxes across 20 domains. Scale includes 60 inboxes across 30 domains. If you need more capacity than your plan supports we can discuss an expansion.
What happens if one inbox gets flagged?
We pause that inbox immediately and redistribute its volume across the remaining inboxes in the pool while we investigate. The campaign continues running at slightly reduced volume rather than stopping entirely. We cover the repair process in more detail in the Spam Recovery article.
Can we use our own email provider?
Yes. We work with Google Workspace and Microsoft 365. Both support the authentication standards and sending configurations we need. We will advise on which is better suited to your setup during onboarding.