Scaling an MSP Past Referrals, Run Through Instantly
Every MSP hits the same wall: referrals built the first hundred clients, but referrals don't compound on a schedule. The firms that break through treat outbound like they treat monitoring — a system that runs continuously at known capacity, not a heroic push when the pipeline looks thin. Instantly is built for exactly that operating mode: unlimited email account connections, a simple campaign builder, and analytics that tell you which offer is actually working.
But Instantly is the sending and sequencing layer, not the infrastructure. Those campaigns need domains, mailboxes, and IPs underneath them — and that's ColdRelay: dedicated mailboxes on isolated Azure tenants with dedicated IPs, provisioned in about an hour. This guide covers wiring the two together and running outbound as a capacity-planned system: mailbox math per metro, offer testing, and a 90-day rhythm matched to how IT contracts actually turn over.
Why Run Instantly on ColdRelay Infrastructure
Instantly's paid plans let you connect unlimited email accounts — which is exactly the right model for an MSP scaling outbound, because it means the sending software never becomes the bottleneck. But unlimited connections aren't unlimited mailboxes. Instantly connects to accounts; something still has to provision the domains, configure the DNS, and stand up mailboxes that deliver. That's the infrastructure layer, and it's where ColdRelay fits.
Instead of buying workspace seats one at a time and configuring DNS by hand, you order dedicated mailboxes on isolated Azure tenants with dedicated IPs, fully DNS-configured (SPF, DKIM, DMARC) and ready in about an hour. ColdRelay supports 100-150 mailboxes per domain, and the CSV export drops straight into Instantly's bulk SMTP/IMAP import — so growing from 20 mailboxes to 200 is a purchasing decision, not a weekend of DNS work.
For an MSP running outbound as a system, that's the whole point: capacity you can provision on demand, deliverability you can count on (95%+ inbox placement), and a sending platform that scales with it. ColdRelay is the infrastructure, Instantly is the engine on top — additive, not competitive.
Visit Instantly →Connecting ColdRelay Mailboxes to Instantly
Size the mailbox pool from your capacity math, then provision
Work backwards from coverage targets: at 2 outbound sends/day per mailbox (4 sends/day total — 2 outbound + 2 warmup), 25 mailboxes covers about 1,500 prospects a month at a 3-touch cadence — roughly one metro's worth of 10-150 seat businesses. Provision that pool on ColdRelay using secondary domains separate from your primary firm domain; everything stands up on isolated Azure tenants with dedicated IPs in about an hour, with SPF, DKIM, and DMARC pre-configured.
Export credentials as CSV from ColdRelay
From the ColdRelay dashboard, export the mailbox list with SMTP/IMAP credentials. The CSV matches the column layout Instantly's bulk importer expects, so a 25-mailbox pool — or a 150-mailbox one — imports in one pass with no manual reformatting.
Bulk-import the accounts in Instantly
In Instantly, go to Email Accounts → Add New → Bulk Import via CSV (SMTP/IMAP). Instantly validates the connections and adds every ColdRelay mailbox as a sending account. This is where Instantly's unlimited-accounts model pays off: connecting mailbox number 200 costs the same as mailbox number 20.
Set sending limits to the ColdRelay budget
Set each account's daily campaign limit in Instantly to 2 outbound emails per day, mirroring ColdRelay's per-mailbox budget of 4 sends/day total — 2 outbound + 2 warmup. ColdRelay's warmup runs continuously inside that budget, so skip Instantly's own warmup pool and launch the same day you provision.
Build the campaign with A/Z variants and launch
In Instantly's campaign builder, create your sequence and load competing offer angles as A/Z test variants — managed-services retainer framing in one, a project-based entry offer in another. Attach the full mailbox pool, launch, and let Instantly's analytics tell you which offer earns replies before you commit the next metro's worth of sends to it.
The MSP Scale-Up Instantly Playbook
Do the capacity math per metro before you write a single email
Pull the count of 10-150 seat businesses in each metro you serve, then size the mailbox pool to cover it on a quarterly cycle: at 2 outbound sends/day per mailbox, 25 mailboxes works one metro, 75 works three. Expanding into a new city becomes a provisioning event — order another tranche of ColdRelay mailboxes, bulk-import to Instantly, clone the campaign — instead of a six-month branch-office gamble. Outbound capacity becomes a number you plan, like seats under management.
A/Z test the offer, not just the subject line
Most MSPs don't know whether their market responds better to the recurring pitch ("flat monthly IT, everything covered") or a project-based foot in the door ("fixed-fee migration, then decide"). Instantly's A/Z testing settles it empirically: run both offers as variants in the same campaign against the same list, and let reply rate — not opens — pick the winner. Project-entry offers often win the first meeting while retainer framing wins larger accounts; knowing which is true in your market is worth more than any copy tweak.
Run a 90-day rhythm matched to contract cycles
IT contracts renew annually, which means at any moment roughly a quarter of your market enters its evaluation window in the next 90 days. You can't know which quarter — so the play is constant presence: a steady drumbeat of sends every week, with re-touches on a 90-day cycle so each prospect hears from you about four times a year. The MSP that's in the inbox the week the incumbent fumbles a ticket wins the switch. Burst campaigns miss those windows; rhythm catches them.
Work Unibox like a ticket queue, not an inbox
An MSP already runs on response-time SLAs — apply the same discipline to outbound replies. Instantly's Unibox pulls responses from every connected mailbox into one queue: triage it twice a day, tag interested replies, and hold a same-business-day first-response SLA, because a prospect who answers a cold email is comparing your responsiveness against the incumbent's from the first message. As the mailbox pool grows past 50 accounts, Unibox is the difference between scaling sends and scaling chaos.
Typical MSP Scale-Up Benchmarks (Instantly + ColdRelay)
| Metric | Benchmark | Notes |
|---|---|---|
| Inbox placement rate | 95%+ | Dedicated IPs and isolated tenants outperform shared Google/Microsoft pools |
| Reply rate | 3-6% | Offer-tested campaigns at steady cadence; the winning A/Z variant typically sits at the top of the range |
| Outbound capacity per mailbox | 2/day | 4 sends/day total per mailbox — 2 outbound + 2 warmup |
| Mailboxes to cover one metro quarterly | 20-30 | Assumes ~1,500 target businesses per metro on a 3-touch, 90-day cycle |
| First touch to signed agreement | 60-120 days | Matches annual contract evaluation windows — why rhythm beats bursts |
What It Costs: Instantly + 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 the capacity-planning model, since the per-mailbox cost of metro number three is lower than metro number one. DNS, dedicated IPs, and isolated Azure tenants are included.
Instantly is billed separately on its own subscription for campaigns, A/Z testing, Unibox, and analytics — with unlimited email account connections on paid plans, so the software cost stays flat as your mailbox pool grows.
The combination is built for scaling: Instantly's flat unlimited-accounts pricing plus ColdRelay's declining per-mailbox tiers means your cost per prospect reached actually drops as the system grows — the opposite of per-seat workspace pricing.
| 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; Instantly handles the sending, sequencing, and inbox rotation on top.
Frequently Asked Questions
Does ColdRelay replace Instantly?
No — they're complementary layers of the same stack. Instantly is the sending and sequencing software: campaigns, A/Z testing, Unibox, analytics. ColdRelay is the infrastructure underneath: the secondary domains, mailboxes, and dedicated IPs that Instantly's campaigns actually send from. You connect ColdRelay mailboxes to Instantly and run both together.
Instantly includes unlimited email accounts — why do I need ColdRelay?
Unlimited accounts means Instantly won't charge you more for connecting more mailboxes — it doesn't mean Instantly provides the mailboxes. Someone still has to register the domains, configure SPF, DKIM, and DMARC, and provision mailboxes that deliver. ColdRelay does that part: dedicated mailboxes on isolated Azure tenants with dedicated IPs, 100-150 per domain, ready in about an hour. Instantly's unlimited model is what makes ColdRelay's volume tiers worth using — the software never caps how much infrastructure you can attach.
How many mailboxes do I need to expand into a new metro?
Run the capacity math: count the target businesses in the metro (typically 1,000-2,000 in the 10-150 seat range for a mid-size city), decide your touch cadence, and divide. At 2 outbound sends/day per mailbox — half of the 4/day total budget, the rest being warmup — 20-30 mailboxes covers a typical metro on a quarterly cycle. Each new metro is another tranche of the same size, bulk-imported into Instantly via CSV.
Should I run Instantly's warmup on ColdRelay mailboxes?
No need. ColdRelay mailboxes warm continuously as part of their standing budget — 2 warmup sends/day per mailbox alongside 2 outbound, 4 sends/day total — so there's no separate warmup period before your first campaign. Provision in the morning, bulk-import to Instantly, and launch the same day; warmup keeps running in the background for the life of the mailbox.