# How Many Domains and Mailboxes Do You Need for Outreach?
The right number of outreach domains and mailboxes depends on your planned number of target companies, touchpoints per company, list quality and campaign timeline. Calculate the pool from the total campaign plan, then distribute activity across separate domains and mailboxes with capacity in reserve. Do not use your main corporate domain for cold outreach: it supports client and partner correspondence and should not depend on the outcome of a cold campaign.
**Figures:** 97.7% — of addresses accepted the email in OT9 campaigns; 1,100 — sending mailboxes across OT9 campaigns
## Why can’t you put all email volume through one mailbox?
This may look like a simple division problem. In a real B2B campaign, it is a question of whether the entire email setup remains stable. Mail providers assess more than sending volume: they also consider address quality, reply patterns, complaints and the technical reputation of the domain and mailbox. Build the plan from the campaign’s total scope and timing, not from a desire to get the most out of one account.
Your main domain is for negotiations, invoices and existing customers. It should not be exposed to a cold-audience experiment. Use a separate domain and mailbox pool for outbound outreach so normal business correspondence is insulated from campaign results. Read more about the technical side in our guide to email deliverability for Russia and the CIS.
> A sound calculation always leaves headroom. If a campaign only works when every mailbox operates at its limit, the setup is already fragile.
- Plan volume by unique companies and planned touchpoints, not by the size of a contact file.
- Distribute mailboxes across domains so one issue does not stop the entire campaign.
- Account separately for replies, opt-outs and contacts whose email addresses need further checking.
## What do you need to calculate the right domain pool?
You do not need to grant access to your existing email to make this calculation. You do need a clear campaign plan: who you will contact, how many companies belong in the first wave, whether the conversation will continue by email, and how much of the list needs address verification. If one list combines manufacturing buyers, agency owners and branch directors, fix the campaign structure before increasing the mailbox count.
| Question to answer | What it changes | What to check on handover |
|---|---|---|
| How many companies are in the wave? | The size of the pool and campaign duration | The calculation is based on companies, not an abstract number of emails |
| How many touchpoints are planned? | The workload on the infrastructure and the list size required | No further touchpoint goes to a contact who has already replied |
| How reliable are the contacts? | Delivery risk and the need for additional verification | Questionable addresses have their own status |
| Which channel continues the conversation? | Whether email needs to carry the conversation after the first touch | Channel roles are clear rather than duplicated |
A common mistake is to promise full-market coverage in a short period simply by adding mailboxes. A list may contain generic inboxes, outdated records and several roles for the same company. The visible volume is large at the start, but delivery issues rise and sales receives replies without useful context. Start with email list verification, then calculate the campaign pace.
## What should be in place before the first email goes out?
A domain and mailbox alone do not make a working outreach infrastructure. Before launch, confirm that the sender is correctly authenticated, replies reach the right queue and the domain’s technical records are aligned. You do not need to configure this yourself, but you should accept the work through clear evidence rather than a screenshot of newly created mailboxes.
### Handover checklist
A poor handover is a list of created addresses presented as completed work. A useful handover lets you verify the reply route, see the status of every touchpoint and know who answers a request for details. Plan the transfer of interest to sales in advance with CRM integration for outreach leads.
## When will a larger mailbox pool not help?
Infrastructure cannot fix an unclear offer. If you cannot explain in two or three sentences what problem you solve, for whom, and why a conversation matters now, adding domains will only reveal the lack of interest faster. The same applies to a list with no selection criteria: an email that reaches a random recipient is not lead generation.
This approach is not a fit if you need immediate deals from a narrow list of a few companies, your sales team cannot respond to inbound interest, or the main corporate domain is the only channel you are willing to use. For focused work with a limited account list, consider an account-based marketing campaign instead of building a broad outbound flow.
1. Agree on the target segment, offer and expected size of the first wave.
2. Review the list and separate contacts that need verification.
3. Build and check separate infrastructure before sending.
4. Launch with transparent reporting on delivery and replies.
5. Adjust the next wave based on evidence, not a promise of a fixed number of leads.
## What does OT9 handle?
We calculate the domain and mailbox pool for the campaign, prepare the infrastructure, monitor its condition and keep it separate from your everyday corporate email. We then connect the technical setup with the list, copy and reply handling. That is how planned volume becomes a controlled campaign rather than a bulk send.
Across 360 campaigns, we have sent 3,224,000 emails and contacted 811,200 companies. To assess your campaign before launch, request a free cold outreach audit or see how we work.
## Frequently asked questions
**Can I run cold outreach from my company’s main domain?**
We do not recommend it. Your main domain supports correspondence with customers, partners and suppliers, so it should not be tied to the risks of a cold campaign. Use separate outreach infrastructure instead.
**How many domains do I need for one campaign?**
It depends on the number of target companies, touchpoints, list quality and campaign timeline. A reliable answer comes from calculating the whole campaign, not choosing an arbitrary number of domains first.
**Why not simply create more mailboxes?**
A larger pool does not improve a weak offer, an inaccurate list or slow reply handling. Its purpose is to distribute an agreed campaign volume safely, not to accelerate sending mechanically.
**How can I tell whether an agency prepared the infrastructure properly?**
Ask to see that the pool is separate from your main email, where replies are routed, the results of technical checks and the reporting structure. The key evidence is campaign readiness and control, not the number of addresses created.
**Does list quality affect the number of mailboxes required?**
Yes. Invalid and uncertain contacts increase delivery risk and distort the picture of campaign performance. Verify the list before finalising the campaign volume and before sending.
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Source: https://ot9.ru/en/guides/skolko-yashchikov-nuzhno/ · OT9 (KAP Group) · updated 2026-08-10