Workflow · Email + LinkedIn infrastructure

Cold email that actually lands.

Domain procurement, DNS, inbox warmup, deliverability monitoring, LinkedIn outreach automation. All infra owned and operated by us. Plus pre-warmed domain inventory ready to send this week — skip the 3-week warmup when you need to test fast.

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The bottleneck

47% of cold email hits spam. The fix isn't a better subject line.

47%
Of cold outbound emails route to spam at the gateway
14-21 days
Minimum warmup runway for a new domain to land in primary
0.3%
Gmail's spam-complaint kill-switch (stay under 0.1%)

If your open rate is under 40%, it's an infrastructure problem — not a copy problem. The stack underneath cold email is non-obvious: 5-10 lookalike .com domains so you never burn your primary, 3 mailboxes per domain capped at ~20 sends/day, SPF/DKIM/DMARC clean, a 14-21 day warmup before any cold send goes out, complaint rate held under 0.1%, reputation tracked daily in Postmaster. We own the whole thing so your team never has to learn what an SPF record is.

How we work

Four weeks. Ready to send.

  1. Week 01

    Domains land.

    5-10 lookalike .coms shortlisted with you (tryacme.com, acmehq.com, getacme.com) and registered across diversified registrars — never your primary. SPF, DKIM, and DMARC records propagated. MX wired into Workspace or M365. Verified clean across Gmail, Outlook, and Yahoo.

  2. Week 02

    Warmup begins.

    3 mailboxes per domain provisioned with real profile photos. Smartlead or Instantly warmup tools running at 5 sends/day, ramping by 5 daily toward ~40-65. Google Postmaster checked every morning. Any domain dropping to Low reputation gets pulled before it burns the pool.

  3. Week 03

    Volume ramps.

    After 14-21 days of warmup, real sends start at 20/inbox/day with spintax variants on every line. Inbox-placement seed-tests weekly. LinkedIn accounts paired in parallel with manual warmup — IPs rotated, daily limits respected, zero bans in production deployments to date.

  4. Week 04

    Ready to send.

    Full inbox-health report delivered. Sequencer wired into your CRM. First cold sends graduated from the warmup pool — bounce held under 2%, complaints under 0.1%, replies threaded into a single inbox and routed to your Slack within minutes.

In production

How it looks in production.

Case 01 · Series B SaaS scaling outbound to 50k contacts/month

32 domains, 96 inboxes, zero burned in 90 days.

Problem.

Existing setup: 8 domains, 24 inboxes, primary-tab placement collapsing below 60%. Reply rates falling, deliverability blocklists creeping in, primary sending domain at risk. Sales team blaming product; product team blaming sales.

What we did.

Fresh sending stack stood up parallel to the existing one. 32 separate sending domains registered and warmed for three weeks. 96 inboxes across them, three per domain, each sending 30/day. SPF/DKIM/DMARC tuned. Migration cut over inboxes over six weeks while we monitored deliverability per inbox in real time.

98%+
Primary-tab placement · 90 days
0
Inboxes burned
“We went from worrying about deliverability every Monday to not thinking about it at all.”— Head of Growth
Case 02 · Seed-stage AI company recovering from a domain burn

Primary domain off the Spamhaus list in 17 days.

Problem.

Founder had been running outbound from their primary @company.com sending alias. Volume crept up, complaint rate spiked, Spamhaus blocked the root domain. Inbound demo requests stopped landing. Investors couldn't reach the team.

What we did.

Hard cut over to a separate sending estate within 48 hours. Three new domains registered, parked-then-warmed in parallel. Worked the appeal queue at Spamhaus with documented complaint-handling. Cleaned the original list, killed the worst-performing segments, restored sending discipline.

17 days
Time to delist
0
Days primary email was actually broken
“They moved faster than the team that caused the problem in the first place.”— Founder & CEO
Case 03 · Agency standing up outbound for 14 clients

From spreadsheet chaos to one source of truth.

Problem.

Outbound agency running 14 active clients across as many sending stacks. No central monitoring. Inboxes randomly cooling off. Clients churning when deliverability dipped — by the time the agency noticed, it was already a fire.

What we did.

Centralized sending estate with per-client domain isolation. 84 inboxes across 28 domains, mapped to clients. Real-time bounce, complaint, and reply monitoring in a shared dashboard. Per-client warmup playbooks codified. Account-level Slack alerts when any client's deliverability score dropped.

14 → 22
Client roster · 9 months
<2%
Bounce rate, all clients
“We finally have a sending stack we can actually scale on. Onboarding a new client is now a one-day job.”— Agency Founder
Free calculators

Plug in your numbers — do the math.

Calculator

Email inbox calculator

How many inboxes and domains you need for your target reply volume. Built on the same constraints that drive real sending estates.

Open the calculator
Calculator

Multi-channel calculator

Plan email + LinkedIn outreach together. See the combined footprint required for your meeting target.

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Knowledge base · 14 guides

Read the email infrastructure playbook.

Start here5 min

Complete email infrastructure setup

The full 14-guide walkthrough. SPF, DKIM, DMARC, MTA-STS, BIMI, ARC, subdomain isolation, warmup, bulk-sender compliance, monitoring, and reply detection.

Read the guide
Operations12 min

Inbox warmup, demystified

Why 2-3 weeks isn't optional. Engagement curves, the ramp methodology, and why volume-based synthetic warmup is now detected at major receivers.

Read the guide
Architecture13 min

Subdomain isolation — the reputation firewall

Why founders should never run cold outbound from their corporate domain. The 32-domain math for a 30-rep team, and the lookalike domain pattern.

Read the guide
Browse all guides in the knowledge base →
Frequently asked

Common questions.

How fast can you start?
Forty-eight hours from Slack invite to first domains on the registrar. First mailboxes live by end of week one. Full sending stack ready at 28 days.
Do I keep the domains and inboxes if we stop working together?
Yes. Everything is registered under your entity, billed to your card, on your provider accounts. Nothing runs through our infrastructure — engineer leaves your Slack, your stack stays yours.
What sending platform do you use?
Platform-agnostic. Smartlead, Instantly, Apollo, Outreach, Salesloft — whatever fits the motion. If you're already on one, we slot in. If not, we'll pick based on volume and ICP.
Will my LinkedIn accounts get banned?
Not in any production deployment to date. Multi-account architecture, IP rotation, conservative daily limits, manual warmup. The accounts that get nuked are the ones running 80 connects on day one.
How much does this cost the company per month?
Custom per workflow — book a call to scope. The infra itself (domains, mailboxes, warmup, sequencer) runs $1,500-$4,000/mo depending on volume. Our engineering fee is on top.
Do you have pre-warmed inventory we can borrow?
Yes. We maintain a pool of pre-warmed .com and .ai sending domains, ready to send the same week you onboard. If you need to test a campaign in 5 days instead of 3 weeks, we can start on our domains while your owned infrastructure warms up in parallel. Once your domains are ready, we cut over.
Are the emails AI-generated?
No. We use AI for everything that scales — list-building, enrichment, signal tracking, sequencing — but every email body is handwritten or human-reviewed before send. Pure-AI copy is detectable in under 5 seconds and burns deliverability. The whole point of investing in this infrastructure is to send well, not to send fast slop.
Are you an agency?
No. We're an engineering team. The person in your Slack writes code, owns the deliverability dashboard, and is on call when a domain shows up on Spamhaus.
Let's talk

Need inboxes by next month?

Sending infrastructure provisioned, warmed, and ready in four weeks. No tools to buy. No SDR to hire. We own the stack.

Talk to us today →
Or email phillip@allstonlabs.com