Vertical Campaign Portfolios, Run Through Smartlead
The web design agencies that get the most out of cold email don't run one big campaign to "businesses that need a website." They pick two or three verticals — say dental practices, law firms, and home services — and run a permanent campaign per vertical, each with its own copy, its own proof, and its own reply-rate scoreboard. The campaigns never really end; they get reviewed weekly, and capacity flows toward whichever vertical is replying.
Smartlead is well suited to running that kind of portfolio: campaign-level mailbox rotation lets you decide how much sending capacity each vertical gets, spintax keeps a single template feeling local across hundreds of cities, and the master inbox puts replies from every vertical in one triage queue. What Smartlead doesn't do is provision the infrastructure underneath — the secondary domains, mailboxes, and dedicated IPs the portfolio actually sends from. That's where ColdRelay fits. This guide covers how to wire the two together and how to run the weekly operating rhythm that makes a vertical portfolio compound.
Why Run Smartlead on ColdRelay Infrastructure
Smartlead is a sending and sequencing platform — it sends from whatever mailboxes you connect, rotates across them at the campaign level, and pools every reply into its master inbox. It doesn't create the domains or mailboxes; that's the infrastructure layer's job.
A vertical portfolio makes that layer's reliability unusually important, because the whole model depends on comparing reply rates across campaigns week over week. If deliverability is wobbling underneath you, a "losing" vertical might just be a vertical whose sends stopped landing — and you'll reallocate capacity based on noise. ColdRelay takes that variable off the table: mailboxes provision on isolated Azure tenants with dedicated IPs, with SPF, DKIM, and DMARC pre-configured, ready in about an hour, holding 95%+ inbox placement. When placement is constant, reply-rate differences between your dental, legal, and home-services campaigns mean what they appear to mean.
The pairing is additive, not competitive: ColdRelay is the infrastructure, Smartlead is the sender on top. You keep Smartlead's campaign-level rotation, spintax, and master inbox — you just run them on mailboxes built to land.
Visit Smartlead →Connecting ColdRelay Mailboxes to Smartlead
Provision a portfolio-sized pool on ColdRelay
Pick secondary domains adjacent to your agency brand — never the domain that hosts your portfolio. ColdRelay supports 100-150 mailboxes per domain, so a three-vertical portfolio running 30-60 mailboxes fits comfortably on one domain. Everything provisions on isolated Azure tenants with dedicated IPs in about an hour, with SPF, DKIM, and DMARC already configured — no warmup waiting period, since warmup runs continuously as part of each mailbox's budget.
Bulk-import the mailboxes under Email Accounts
Export your mailbox list with SMTP/IMAP credentials from the ColdRelay dashboard. In Smartlead, go to Email Accounts → Add Account and use the bulk CSV import to connect the whole pool in one pass. If you also run outbound for clients, Smartlead's client sub-accounts let you keep each client's mailboxes and campaigns in a separate workspace.
Set daily limits to match the ColdRelay budget
Set each mailbox's daily campaign limit in Smartlead to 2 outbound emails per day, mirroring ColdRelay's per-mailbox budget of 4 sends/day total — 2 outbound + 2 warmup. ColdRelay handles the warmup side continuously, so point Smartlead at outbound only rather than double-warming.
Build one permanent campaign per vertical, localized with spintax
Create three Smartlead campaigns — one per vertical — each with copy in that vertical's vocabulary and a proof link to a live site you built in that niche. Use Smartlead's spintax to vary the local references ({{Phoenix|Scottsdale|Mesa}}-area practices, "clinics around {{city}}") so one dental template reads like a local email in every market you prospect, instead of an identical blast fingerprinted across hundreds of inboxes.
Allocate mailboxes with campaign-level rotation and launch
Attach mailboxes to each campaign using Smartlead's campaign-level rotation — an even split to start, say 15 mailboxes (30 outbound sends/day) per vertical. This allocation is the dial you'll turn in the weekly review: rotation assignments can shift toward the winning vertical without provisioning anything new. If you white-label reporting for clients, Smartlead's API and webhooks can push per-campaign stats into your own dashboard.
The Vertical Portfolio Smartlead Playbook
Run verticals like a portfolio, not a target list
Pick three verticals with different economics — one high-ticket (legal), one volume (home services), one in between (dental) — and give each a permanent campaign. The point isn't to find the perfect niche up front; it's to put three bets on the table and let four weeks of reply data tell you where your agency's proof actually resonates. Most agencies guess their best vertical wrong.
Spintax the geography, not the pitch
Keep the core pitch of each vertical campaign fixed so your weekly comparisons stay clean — if the dental copy changes every week, you can't tell whether the vertical or the rewrite moved the numbers. Spend your spintax budget on local texture instead: city names, regional phrasing, neighborhood references. A template that says "dental practices around {{city}}" earns local-email treatment from a thousand different inboxes while remaining one measurable campaign.
Hold a 20-minute weekly portfolio review
Same day every week, pull per-campaign reply rates from Smartlead and reassign mailbox rotation accordingly: the leading vertical gets mailboxes from the trailing one. After four weeks, if a vertical is consistently last, retire it and trial a replacement — med spas, accounting firms, veterinary clinics — using the freed-up mailboxes. Because ColdRelay capacity provisions in about an hour, swapping a vertical into the portfolio is a same-day operation, not a project.
Triage the master inbox by vertical value, not arrival time
Smartlead's master inbox pools replies from all three campaigns into one queue — which is efficient, but only if you don't work it top-down. Tag replies by vertical and answer the highest-LTV vertical's interested replies first: a law firm redesign retainer is worth several home-services builds. The reply data doubles as portfolio input — a vertical whose replies say "who are you?" needs better proof, while one whose replies ask about price needs more mailboxes.
Typical Vertical Portfolio Benchmarks (Smartlead + ColdRelay)
| Metric | Benchmark | Notes |
|---|---|---|
| Inbox placement rate | 95%+ | Dedicated IPs and isolated tenants keep placement constant — so reply-rate differences between verticals are real signal |
| Reply rate per vertical campaign | 2-6% | Home services and dental typically reply at the top of the range; legal lower but at much higher project value |
| Reply-rate spread between best and worst vertical | 2-3x | The gap is the whole point of the portfolio — it tells you where to move mailbox rotation |
| Outbound capacity per mailbox | 2/day | 4 sends/day total per mailbox — 2 outbound + 2 warmup |
| Weeks to a confident vertical verdict | 3-4 | At ~30 outbound sends/day per vertical, a month of data is enough to promote, hold, or retire |
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). DNS, IPs, and isolated Azure tenants are included — and because rotation, not provisioning, is how capacity moves between verticals, the mailbox count stays stable while the portfolio shifts.
Smartlead is billed separately on its own subscription for campaigns, campaign-level rotation, spintax, the master inbox, and client sub-accounts — priced per its current plans.
Infrastructure cost scales with total mailbox count, not with how many vertical campaigns you run — three campaigns share one ColdRelay pool. One bill for sending capacity, one for the sending software, and the weekly review decides how the capacity is spent.
| 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?
No. They're complementary layers. Smartlead handles the vertical campaigns, campaign-level mailbox rotation, spintax, and the master inbox. ColdRelay provides the underlying domains, mailboxes, and dedicated IPs that Smartlead sends from. You use them together — infrastructure underneath, sending software on top.
Why three verticals instead of one niche or ten?
One vertical is a single bet with no comparison data — if it underperforms, you can't tell whether the problem is the niche or your outbound. Ten verticals spread 2 outbound sends/day per mailbox too thin to reach a verdict on any of them. Three permanent campaigns sharing one ColdRelay pool gives each vertical enough volume for a confident read within 3-4 weeks, while the weekly review keeps capacity flowing toward whichever one is winning.
Does heavy spintax hurt deliverability?
Used the way this playbook uses it — varying city names, local references, and phrasing — spintax helps, because no two inboxes receive an identical email and the campaign avoids template fingerprinting. What protects deliverability is the infrastructure discipline underneath: ColdRelay keeps every mailbox inside the 4 sends/day budget (2 outbound + 2 warmup) on isolated Azure tenants with dedicated IPs, which is how the stack holds 95%+ inbox placement regardless of how much you spin the copy.
Can I run this portfolio model for my agency's clients too?
Yes — it transfers cleanly. Smartlead's client sub-accounts keep each client's campaigns and mailboxes in a separate workspace, and its API and webhooks let you push per-vertical stats into a white-labeled report. On the infrastructure side, provision a separate ColdRelay mailbox pool per client (each ready in about an hour, with ColdRelay supporting 100-150 mailboxes per domain) so no client's sending reputation ever depends on another's.