Cold outreach without renting a mailbox farm

The standard outreach setup is three domains, five mailboxes on each, and a tool to rotate between them. Fifteen Google Workspace seats at $7 per user per month on annual billing is $105 a month, verified against Workspace pricing in August 2026, and that is before the sequencer, the warm-up subscription, and the next three domains you will buy when these ones stop landing.

The farm exists for a billing reason and a folklore reason. The billing reason: every mailbox is a seat, and per-seat products cap what one seat may send, so volume gets bought in units of mailbox. The folklore reason is burn and rotate, which assumes domains are consumable. It does produce meetings. It also means permanently buying domains and permanently warming them, because domain reputation takes four to eight weeks to mature and none of it transfers to the next one you buy.

Here is the part the farm does not solve. More mailboxes do not buy more permission. Gmail's bulk-sender line sits at 5,000 messages a day, but the authentication and complaint rules apply at any volume, and Gmail has hard-rejected unauthenticated mail since November 2025 (Microsoft since May 2025). Cross a 0.3 percent spam-complaint rate and Google withholds delivery mitigation until you have stayed under it for seven consecutive days. Your ceiling is complaint math, and complaint math does not care how many inboxes you split the sending across.

What LetterDuck replaces

An address here is a routing rule on a catch-all, not a paid mailbox. Every address on the domain lands in one threaded inbox, you reply from whichever identity the thread belongs to, and the reply carries In-Reply-To and References headers so it threads in the prospect's client instead of arriving as an orphan. Mailbox providers weight replies above clicks and clicks above opens, which makes the inbound half of outreach the half that builds reputation.

The math at your size

Public list prices, August 2026, annual billing where offered. Google Workspace: Business Starter at $7 per user per month on annual billing. Business Standard is $14 and Business Plus $22. Month-to-month billing costs 20 percent more. Zoho Mail: Mail Lite at $1 per user per month, billed annually only ($12 per user per year, paid up front). LetterDuck is $50 per domain, flat, unlimited addresses and subscribers.

Read the Zoho column and take it seriously. Mail Lite is $1 per user per month prepaid annually, so fifteen mailboxes is $15 a month, and no amount of arguing makes $50 smaller than that. If cheap mailboxes are the entire requirement, buy Zoho and stop reading. What $15 does not buy is a warm-up ramp, a suppression list checked before every send, an auto-pause when complaints climb, or a workspace where a colleague can see the thread.

Against Workspace and Microsoft 365 the crossover lands at eight mailboxes on the cheapest plan either sells. Below that they cost less than we do. Above it their meter keeps running, and the addresses you add here cost nothing because they were never seats.

What the send path enforces

These are not settings you can talk yourself out of at 11pm before a launch:

• Warm-up starts near 150 sends on day one and multiplies about 1.4x daily, reaching roughly 1,100 a day by day seven.
• Days 8 to 28 grow 10 to 20 percent a day, with 0.1 percent complaints as the target we hold to and bounces under 2 percent.
• The path halts itself at a 0.3 percent complaint rate or a 2 percent bounce rate. No judgment call, no override in the moment.
• A suppression list is checked before every single send. Hard bounces are suppressed permanently; soft bounces retry about three times over fourteen days.

Those gates are hard-coded because the alternative is a person deciding, and the person always decides to send. How many cold emails per day is actually safe shows the arithmetic, and the full build, registrar to first message, is in our cold email infrastructure guide.

What we will not do

We are not a blast tool, and we will not send to a purchased or scraped list. That is not a policy we enforce reluctantly; it is the reason the rest works. A bought list is a complaint rate waiting to happen, and complaint rate is the only currency in this channel. We do not rotate mailboxes across burner domains either, and we do not sell warm-up pods, which are a closed and detectable pattern.

There is no sequencer here. No automated follow-up steps, no branching cadences, no CRM sync.

Who should not pick LetterDuck

If your plan is thousands of sends a day across dozens of rotating mailboxes, skip us. That model needs tooling we do not build and volumes our throttle will refuse, and you should read that as a recommendation to buy a real outreach platform rather than an invitation to work around us. Skip us too if the outreach is meant to leave from your main company domain, which we would argue against whatever vendor you use: separate the sending domain first, for the reasons in cold email domain setup. Check the legal footing for your market too, which is cold email legal covers for CAN-SPAM and GDPR.

Who fits: an operator running deliberate, researched outreach from one domain they intend to keep, who wants the replies in a shared inbox and the guardrails in the software. If that is a mailbox question as much as a sending question, LetterDuck vs Google Workspace and LetterDuck vs Zoho Mail price both sides.