Founder-Led Outbound, Run Through Instantly
At the pre-PMF stage, outbound usually isn't a department — it's the founder, sending between product work, investor updates, and everything else. Instantly is a natural fit for that reality: low entry price, a campaign builder you can learn in an afternoon, and unlimited email accounts on paid plans so the software never caps how much infrastructure you connect. What Instantly doesn't give you is the infrastructure itself — the domains, mailboxes, and IPs your campaigns actually send from.
That's the half ColdRelay covers. This guide walks through how early-stage startups wire the two together: provisioning sending infrastructure on ColdRelay in about an hour, importing it into Instantly via CSV, and running design-partner and first-customer outreach without ever putting your main startup domain at risk.
Why Run Instantly on ColdRelay Infrastructure
Instantly is a sending and sequencing platform — campaigns, rotation across accounts, and the Unibox for replies. It sends from whatever mailboxes you connect, but it doesn't provision domains or control the deliverability of the mailboxes themselves. For a founder, that gap is dangerous: the cheapest path is reusing your primary startup domain or hand-rolling Google Workspace seats, and one deliverability mistake there follows you into every investor intro and customer conversation you send afterward.
ColdRelay closes the gap. You order mailboxes on secondary domains, provisioned on isolated Azure tenants with dedicated IPs, with SPF, DKIM, and DMARC pre-configured — ready in about an hour, with no warmup period needed before sending because warmup runs continuously as part of each mailbox's daily budget. Your startup domain stays untouched.
The pairing is additive, not competitive: ColdRelay is the infrastructure layer, Instantly is the sending layer on top. Instantly's unlimited-accounts model actually rewards this setup — connect as many ColdRelay mailboxes as your stage demands without the software bill moving.
Visit Instantly →Connecting ColdRelay Mailboxes to Instantly
Provision a starter pool on ColdRelay
Most founders start with 20-50 mailboxes on 1-2 secondary domains — enough to learn what messaging works without committing SDR-team money. ColdRelay supports 100-150 mailboxes per domain, so a single domain covers your first scale-up too. Everything provisions on isolated Azure tenants with dedicated IPs in about an hour, DNS (SPF, DKIM, DMARC) already configured.
Export credentials from the ColdRelay dashboard
Export your mailbox list with SMTP/IMAP credentials as a CSV. The column layout matches what sending platforms expect, so the file goes straight into Instantly without reformatting — no per-account manual entry.
Bulk-import into Instantly
In Instantly, go to Email Accounts → Add New → Bulk Import (SMTP/IMAP) and upload the CSV. Because paid Instantly plans allow unlimited email accounts, all 20-50 mailboxes connect under your existing subscription — adding capacity later costs nothing on the Instantly side.
Set daily limits to match the ColdRelay budget
In each account's settings (or via bulk edit), set the daily campaign limit to 2 emails per day. That mirrors ColdRelay's per-mailbox budget of 4 sends/day total — 2 outbound + 2 warmup. Leave Instantly's own warmup pool off for these accounts; ColdRelay's continuous warmup already covers it.
Build your first campaign and watch the Unibox
Create a campaign in Instantly's builder, attach every connected mailbox, and let it rotate sends across the pool. With 25 mailboxes that's 50 outbound sends/day — enough for a founder to follow up on every reply personally. Replies land in the Unibox; for design-partner outreach, answering within the hour is your unfair advantage over funded competitors with SDR queues.
The Startup Instantly Playbook
Never send from the domain investors know
Your primary startup domain carries your fundraise, your product email, and your founder credibility. Run every cold sequence from ColdRelay secondary domains connected to Instantly — a burned domain before product-market fit is a setback most early-stage companies can't afford.
Pitch the design partnership, not the contract
Pre-PMF, your strongest cold offer is access and influence, not a price. Structure Instantly sequences around a design-partner ask — early access, direct line to the founder, roadmap input — and save the commercial conversation for the call.
Treat campaigns as message experiments
You don't know your ICP yet — that's the point of this stage. Run 2-3 small Instantly campaigns with different problem framings against different segments, give each a week, and double down on whichever earns real replies. Speed of iteration beats polish.
The founder works the Unibox daily
Don't route replies to a shared inbox nobody owns. Block 30 minutes a day in Instantly's Unibox and answer as yourself — early prospects reply to founders at rates no SDR script matches, and every conversation is product discovery even when it isn't a sale.
Typical Startup Outbound Benchmarks (Instantly + ColdRelay)
| Metric | Benchmark | Notes |
|---|---|---|
| Inbox placement rate | 95%+ | Dedicated IPs and isolated tenants outperform shared Google/Microsoft pools |
| Reply rate | 3-7% | Founder-signed emails with a design-partner ask outperform standard SDR outreach |
| Outbound capacity per mailbox | 2/day | 4 sends/day total per mailbox — 2 outbound + 2 warmup |
| Starting mailbox count | 20-50 | Enough to test messaging; scale on ColdRelay once a segment converts |
| Time to first campaign | Same day | ~60 minutes to provision on ColdRelay, plus campaign setup in Instantly |
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). DNS, dedicated IPs, and isolated Azure tenants are included — and a 20-50 mailbox starter pool keeps the line item firmly inside a pre-seed budget.
Instantly is billed separately on its own subscription. Its low entry price and unlimited email accounts on paid plans mean the software cost stays flat as you connect more ColdRelay mailboxes.
Infrastructure cost scales with mailbox count; Instantly's cost effectively doesn't. For a founder, that means one predictable software bill and one infrastructure bill that grows only when outbound is actually working.
| 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 compete with Instantly?
No — they're complementary layers of the same stack. Instantly handles campaigns, account rotation, and replies in the Unibox. ColdRelay provides the underlying secondary domains, mailboxes, and dedicated IPs that Instantly sends from. You use them together: ColdRelay underneath, Instantly on top.
How many mailboxes should a startup start with?
Most founder-led teams start with 20-50. At 2 outbound sends/day per mailbox (4/day total including 2 warmup sends), 25 mailboxes gives 50 outbound emails a day — enough volume to test messaging while still replying to every response personally. Since ColdRelay supports 100-150 mailboxes per domain and Instantly allows unlimited accounts, scaling later doesn't require re-architecting anything.
Do I need to run Instantly's warmup on ColdRelay mailboxes?
No. ColdRelay mailboxes warm continuously — 2 warmup sends/day per mailbox as part of the 4/day budget — so there's no waiting period before your first campaign and no need to enable Instantly's warmup pool on top. Point Instantly at outbound sending only.
Will cold outreach put our main startup domain at risk?
Not with this setup. All outbound runs from ColdRelay secondary domains on isolated Azure tenants with dedicated IPs, completely separate from the domain you use for product, fundraising, and customer email. If a campaign underperforms, the blast radius stays on infrastructure that's cheap to replace — not on the domain your company's reputation lives on.