Domains/inboxes per volume, warmup timeline, and compliance
At roughly 30 sends per mailbox per day once fully warmed, and 3 to 5 mailboxes per domain (3 by default): 100 emails/day needs about 4 mailboxes on 1 domain; 500/day needs about 17 mailboxes across 5 domains; 2,000/day needs about 67 mailboxes across 14 domains (5 per domain; at 3 each it would pass the 20-domain limit) — use the calculator below for any other target. Warmup ramps over roughly 4 weeks under a server-enforced cap your agent can't override — 5 sends/mailbox/day in week one, rising to 40/day once fully warmed — but your first send happens on day one of that ramp, not after it finishes. CAN-SPAM compliance is enforced structurally: a required physical postal address and the sender identity captured at setup, injected into the footer of every campaign email, which also carries full RFC 8058 one-click unsubscribe (mailto and hosted-endpoint forms), with a suppression list enforced server-side on every send. Replies sent with the reply tool or the dashboard on an existing thread carry no footer and no List-Unsubscribe header. GDPR is not automated the same way — establishing a lawful basis to contact EU-based recipients remains your own responsibility, the same sender-of-record model used for CAN-SPAM.
How many domains and inboxes do you need per volume?
A target daily send volume translates into a mailbox count and a domain count using two planning assumptions, stated plainly rather than hidden in a formula: 30 sends per mailbox per day once fully warmed (a conservative figure within the 25-40/day range in the deliverability guide), and 3 to 5 mailboxes per domain (3 by default, which the calculator uses until that would pass the 20-domain limit, and 5 when you order more than 10 in your first month). Putting 5 on a domain means fewer domains, but if that domain gets burned, 5 mailboxes stop sending instead of 3.
Worked examples at that same 30/mailbox ratio and 3 per domain (5 per domain where 3 would pass the 20-domain limit):
| Target emails/day | Mailboxes needed | Domains needed |
|---|---|---|
| 100 | 4 | 1 |
| 500 | 17 | 5 |
| 2,000 | 67 | 14 |
With agent-cold-email, one setup_infrastructure call sets up the domain and mailbox counts you specify directly — see the setup guide.
What's the warmup timeline before your first send?
Your first send happens on day one of warmup, not after it finishes — warmup is a volume ramp, not a gate you wait behind. A new mailbox is capped server-side at 5 sends/day in week one, 15/day in week two, 25/day in week three, and 35/day in week four, reaching 40/day once fully warmed on day 29 — a hard limit set by a server-side calendar schedule; on domains Coldrig bought, a mailbox left unused for two weeks drops back to a slower step and climbs again once it sends. Every mailbox also gets the mailbox/warmup vendor's isolated warmup pool automatically during this same ~4-week window, bundled at no extra charge; once the ramp completes, the platform automatically cancels that pool subscription and reputation rides real sending alone. For mailboxes on domains Coldrig bought, if one goes unused for two months, or restarts after being stopped, Coldrig runs warm-up again for a month at no extra charge when it next sends. See the full mechanics, including what warmup can't do.
With agent-cold-email, setup_infrastructure starts this ramp automatically as part of setup, and infrastructure_status reports per-mailbox warmup progress on demand — no need to track which day of warmup each mailbox is on across sessions.
Is CAN-SPAM and GDPR compliance enforced automatically?
CAN-SPAM: yes, structurally. A required physical postal address and the sender identity captured at setup are injected into the footer of every campaign email, and every campaign email carries full RFC 8058 one-click unsubscribe (a List-Unsubscribe/List-Unsubscribe-Post header pair plus the hosted one-click endpoint, honored immediately). A suppression list is enforced server-side on every send. None of this is something your agent has to remember to implement. Replies sent with the reply tool or the dashboard on an existing thread carry no footer and no List-Unsubscribe header. Full detail: the compliance FAQ and the Terms of Service.
GDPR: not the same way. agent-cold-email does not ship GDPR-specific automated tooling (lawful-basis verification, EU data-residency controls, data-subject-request automation). If you're contacting EU-based recipients, establishing a lawful basis to do so under GDPR and applicable ePrivacy rules remains your own responsibility — the same sender-of-record model already used for CAN-SPAM: you are the "sender" and "initiator" of the outreach; this platform sets up and operates the infrastructure on your instructions. We'd rather say this plainly than imply automated GDPR coverage.