Buy Mailboxes for Cold Email Without Shared SMTP Risk

A cold email mailbox is not a seat in a sequencer. It is the account that leaves the message and receives the reply. The purchase usually includes:

1. A sending domain separate from your primary company domain.
2. One or more mailboxes on a real platform.
3. DNS for MX, SPF, DKIM, and DMARC.
4. A path to warm up and ramp.
5. Credentials or a sign in path your sequencer can use.

If the quote only says inboxes and never names the platform, stop and ask.

On shared SMTP, your mail leaves through the provider's servers. When many customers share the same IP ranges, receiving filters see one footprint. Google's own sender guidelines say the activity of any senders using a shared IP address affects the reputation of all senders on that IP. Your domain reputation still matters, but you inherit noise you cannot see or stop. Dedicated IPs remove the neighbours and put the whole ramp on you. Either way, you are managing mail server reputation yourself or through a provider, rather than sending from a mainstream business mail platform. See Dedicated Google Workspace vs Shared Cold Email Infra for the mechanism and symptoms.

Official Google Workspace on dedicated domains, with an admin console you can reach. Receivers already know Workspace. You get a real inbox for replies. Instantly and Smartlead document how to connect Google accounts, usually by signing in with Google (OAuth) or by IMAP and SMTP with app passwords. Your job is to make sure the seats are standard paid Workspace seats in an organization you control, not seats inside someone else's shared tenant.

For the broader dedicated versus shared category, see Dedicated Google Workspace Versus Shared Cold Email Infra. For the Workspace purchase path, see Buy Google Workspace Mailboxes for Cold Email.

1. Platform and licence: Ask if each mailbox is a standard paid Google Workspace seat and whose Google organization is the customer. Vague answers usually mean shared. Prefer a named organization you can open in an Admin console.

2. Domains you control: Can you bring your own domains? If you buy domains through the provider, are they registered to an account you control, and can you move them later? Domains carry months of reputation. Losing them means starting over.

3. Primary domain stays out: Cold email should never run on the domain that carries invoices, hiring, and customer mail. Buy or point dedicated domains close to your brand, redirected to your main site. See Primary Domain Isolation for Cold Email.

4. Authentication before volume: MX, SPF, DKIM, and DMARC must be live and verified on a test email before campaigns. Google's public sender guidelines require SPF or DKIM from every sender to personal Gmail accounts, and SPF, DKIM, and DMARC once you send more than 5,000 messages a day to Gmail. If the provider automates DNS, you should still be able to open the records and confirm them yourself. See SPF DKIM DMARC Setup for Cold Email.

5. Density and capacity plan: Common operator practice is two or three mailboxes per domain, with a soft ceiling around five. Capacity comes from more domains, not from packing one domain. Plan volume with roughly 20 to 40 cold sends per warmed mailbox per day, including follow ups, not with Google's published per user ceiling. See How Many Mailboxes Per Domain for Cold Email.

6. Admin access and 2FA: You need password resets, 2FA enforcement, sign in history, and the ability to remove a mailbox the day someone leaves. Without an Admin console, every incident is a support ticket.

7. Sequencer handoff: Mailboxes should be ready to connect in Instantly and Smartlead using the methods those tools support. If a provider mentions a direct integration or export, ask how it works and check the sequencer's own docs. n8n and other tools that speak IMAP or Google APIs follow the same idea: use documented methods.

8. Warmup and health: Warmup should be clear, adjustable, and optional. Prefer health signals per domain and per inbox. Treat a guaranteed or fixed placement rate as a red flag, and ask how any placement figure is measured. Warmup helps new mailboxes build history; it is not a placement guarantee.

9. Agency separation (if you sell outbound): Ask whether multiple organizations or clearly separated pools are available on the plan you are considering. One client's pause should not touch another client's mailboxes.

The platform is unnamed, or SMTP inbox is the whole description. You cannot get Admin console access. Domains are locked to the vendor with no export path. Setup skips SPF, DKIM, or DMARC because we handle it with no records you can see. The plan assumes one mailbox will carry hundreds of cold sends a day. The pitch leads with a guaranteed or fixed placement rate and cannot say how it is measured.

Work backward from daily cold volume.

1. Pick a steady state per mailbox (often roughly 20 to 40 once warmed).
2. Divide your daily target by that number to get mailbox count.
3. Divide mailboxes by two or three to get domain count.
4. Add a buffer for new domains still in warmup.

Example: 200 cold sends a day at 25 per mailbox needs about eight mailboxes, so three or four domains at two or three mailboxes each. That is a planning sketch, not a rule.

ColdMail sells mailbox infrastructure on official Google Workspace. Domains can be yours (bring your own) or bought through ColdMail. SPF, DKIM, DMARC, and MX are published automatically. You get an official admin panel per domain with 2FA, and provider health indicators for Gmail, Outlook, and Yahoo. AI warmup is available as an optional add on; see coldmail.app for current add on pricing. Multiple organizations are available on supporting plans.

ColdMail is not a sequencer. Mailboxes are ready to connect in Instantly and Smartlead using the methods those tools support, and they work with n8n and other tools. There is no shared SMTP pool in the product.

If you are ready to buy without inheriting a shared pool, set up your mailboxes at coldmail.app, or Book a Strategy Call to size domains and mailboxes for your volume.