Agency Outbound, Run Through Smartlead
Marketing agencies run cold email in two directions at once: outbound for your own new-business pipeline, and outbound as a managed service you deliver for clients. Those are different motions with different domains, different reply handling, and different stakes — a deliverability problem on a client campaign is a churn risk, not just a metrics dip.
Smartlead is built for this split: its client management layer gives every account its own sub-account, campaigns, and reporting. ColdRelay is the infrastructure underneath — the secondary domains, mailboxes, and dedicated IPs each of those sub-accounts actually sends from. This guide covers how agencies wire the two together so your pipeline and every client's pipeline run on cleanly separated sending pools.
Why Run Smartlead on ColdRelay Infrastructure
Smartlead handles the agency-facing software problems — sub-accounts per client, campaign-level mailbox rotation, a master inbox across every account, and an API for white-label reporting. What it doesn't do is provision the domains and mailboxes themselves, or carry their deliverability. That's the infrastructure layer's job, and it's the layer clients are actually paying you to get right.
ColdRelay fills that layer. Instead of spinning up Google Workspace seats per client and configuring DNS by hand every time you sign a retainer, you order mailboxes on isolated Azure tenants with dedicated IPs — SPF, DKIM, and DMARC pre-configured, ready in about an hour. When a new client signs, their sending pool can be live before the kickoff call.
The pairing is additive, not competitive: ColdRelay is the infrastructure, Smartlead is the sender on top. You keep Smartlead's sub-account structure and master inbox — you just give every client a sending pool built to land, and one that's fully separate from the pool pitching your next retainer.
Visit Smartlead →Connecting ColdRelay Mailboxes to Smartlead
Provision separate pools on ColdRelay
Order one pool of mailboxes for the agency's own new-business outbound, and a distinct pool per client — each on its own secondary domains, never the client's primary domain. ColdRelay supports 100-150 mailboxes per domain, and everything provisions on isolated Azure tenants with dedicated IPs in about an hour, DNS (SPF, DKIM, DMARC) pre-configured.
Create a Smartlead client sub-account per retainer
In Smartlead, use Clients → Add Client to create a sub-account for each retainer. Sub-accounts keep campaigns, email accounts, and stats isolated per client — which is exactly the boundary your ColdRelay pools already draw at the infrastructure level.
Import each pool into its sub-account
Export mailbox credentials from the ColdRelay dashboard — the CSV matches the column layout sending platforms expect — then bulk-import via Email Accounts → Add Account inside the matching client sub-account. Client A's mailboxes never appear in Client B's rotation.
Set sending limits and let warmup run on ColdRelay
Set each mailbox's daily limit in Smartlead to 2 outbound emails per day, mirroring ColdRelay's per-mailbox budget of 4 sends/day total — 2 outbound + 2 warmup. Warmup runs continuously on ColdRelay's network, so there's no waiting period before a new client's campaign can start, and no need to double-warm inside Smartlead.
Launch campaigns and wire up white-label reporting
Build each client's sequence in their sub-account, attach the pool, and let Smartlead's campaign-level rotation spread sends across it. Use the master inbox to triage replies across every client daily, and pull campaign stats through Smartlead's API and webhooks into your white-label reporting dashboard.
The Marketing Agency Smartlead Playbook
Never mix your pipeline with client pools
The agency's own new-business outbound and each client's campaigns live on separate ColdRelay domains and separate Smartlead sub-accounts. If a client's list quality tanks a pool's reputation, your own pipeline — and every other client — keeps sending untouched.
Pitch retainers with credibility, not features
Agencies sell trust before scope. Lead your own outbound sequences with a specific client result — one number, one named (or anonymized) client, one timeframe — and make the CTA a strategy conversation, not a proposal. Use Smartlead's A/B testing to run case-study angles against each other per vertical.
Build case-study-driven sequences for clients too
The same logic applies to campaigns you run on clients' behalf: a sequence anchored on the client's proof points outperforms generic value props. Keep a swipe file of which case-study structures convert per industry, and template them as Smartlead campaigns you can clone into new sub-accounts.
Provision ahead of budget season
Agency outbound is seasonal: Q4 and Q1 are when prospects plan next year's budgets and retainers actually get signed. Because ColdRelay mailboxes provision in about an hour and warm continuously from day one, you can scale pools up in October without a multi-week warmup runway — and scale client pools the same way when their busy season hits.
Typical Agency Outbound Benchmarks (Smartlead + ColdRelay)
| Metric | Benchmark | Notes |
|---|---|---|
| Inbox placement rate | 95%+ | Dedicated IPs and isolated tenants outperform shared Google/Microsoft pools |
| Reply rate (agency new-business) | 3-6% | Credibility-led, case-study-first copy to a tight ICP; peaks during Q4/Q1 budget cycles |
| Reply rate (client campaigns) | 2-5% | Varies by client vertical and list quality; anchor sequences on the client's own proof points |
| Outbound capacity per mailbox | 2/day | 4 sends/day total per mailbox — 2 outbound + 2 warmup |
| Time to launch a new client pool | Same day | ~60 minutes to provision on ColdRelay, plus sub-account and sequence setup in Smartlead |
What It Costs: Smartlead + ColdRelay
You pay per mailbox per month for the infrastructure, with volume tiers that drop as you scale (see the table below) — which matters for agencies, since pooling all clients' mailboxes under one account pushes you into better tiers. DNS, IPs, and isolated Azure tenants are included.
Smartlead is billed separately on its own subscription for sequencing, sub-accounts, the master inbox, and API access — priced per its current plans.
Infrastructure cost scales with total mailbox count across clients; Smartlead's cost scales with plan tier and features. Both line items pass through cleanly into per-client retainer pricing — one bill for sending capacity, one for the sending software.
| Mailboxes | ColdRelay price / mailbox / month |
|---|---|
| 1–199 | $1.00 |
| 200–999 | $0.85 |
| 1,000–4,999 | $0.70 |
| 5,000+ | $0.55 |
Each mailbox sends 4 emails per day — 2 outbound to prospects + 2 warmup. ColdRelay provisions mailboxes on isolated Azure tenants with dedicated IPs; Smartlead handles the sending, sequencing, and inbox rotation on top.
Frequently Asked Questions
Does ColdRelay replace Smartlead for agencies?
No. They do different jobs and stack together. Smartlead handles sub-accounts, sequencing, campaign-level rotation, and the master inbox. ColdRelay provides the underlying domains, mailboxes, and dedicated IPs that each Smartlead sub-account sends from. Agencies use both — one is the software, the other is the infrastructure.
Should each client get their own mailboxes, or can clients share a pool?
Each client gets their own pool on their own secondary domains, matched to their own Smartlead sub-account. Shared pools mean shared reputation — one client's bad list damages every campaign in the pool. With ColdRelay supporting 100-150 mailboxes per domain, even a small per-client pool has plenty of room to grow inside the retainer.
How fast can we get a new client's campaign live?
Same day. ColdRelay provisions a client's mailboxes on isolated Azure tenants with dedicated IPs in about an hour, with SPF, DKIM, and DMARC pre-configured — and because warmup runs continuously as part of each mailbox's 4 sends/day budget (2 outbound + 2 warmup), there's no warmup waiting period before the first sequence starts.
Can we white-label this for clients?
Yes — that's the standard agency setup. Clients see your reporting, built on Smartlead's API and webhooks, while the sending runs on ColdRelay infrastructure under domains provisioned for that client. Neither layer needs to appear in the client-facing deliverable unless you want it to.