The closed:in playbook

The B2B outbound playbook
from a Clay & Instantly partner agency

closed:in is a GTM engineering agency in Amsterdam. We build outbound systems for B2B service companies (Verzendbazen, Endresz, Jamezz, Mistertafel and more). After 1,000+ live campaigns we wrote down the exact pre-launch checklist we run before kicking off any client.

Get the 1-page infrastructure checklist as a free PDF. Then ~1 email per week with real tactics from live campaigns.

Used by closed:in for clients like

What's inside the playbook

The infrastructure checklist,
broken into 6 chunks.

Sending domains

How to pick alternate domains, structure subdomains, set up MX records and avoid the domain pitfalls that kill deliverability before you send a single email.

Inboxes & warmup

The exact warmup schedule we use to take a fresh inbox from 0 to 50 emails/day, plus which warmup tool actually works and which ones leak signals.

SPF / DKIM / DMARC

Plain-language explanation of all three records, which values to set for outbound on Google Workspace and Microsoft 365, and how to test that they actually pass.

Lead list hygiene

The Clay waterfall we use to verify business emails, the bounce-rate threshold that gets you to the spam folder, and how to scrub before you send.

Sequence timing

Day-by-day spacing between touches, when to switch from email to LinkedIn, and the cutoff point where follow-ups stop helping and start hurting reply rates.

Reply handling

How to wire replies into Close, HubSpot or Salesforce automatically, the 3 reply categories that matter, and the auto-tag rules we use to keep the SDR inbox clean.

After signup

Your first 14 days
in the newsletter.

Day 0

The infrastructure checklist (PDF)

Instant download with the 6-chunk pre-launch checklist closed:in runs before any client campaign goes live.

Day 2

The detail that kills cold email

Why most teams blame copy when the real failure is upstream. Plus the exact warmup window we use.

Day 5

How Verzendbazen booked 78 opportunities

Mini case study with the Clay list filters, sequence structure and reply rate numbers.

Day 9

4 mistakes we see every week

Subject lines, sending domains, personalisation traps and exit logic. Specific anti-patterns to remove from your campaigns.

Day 14

Soft check-in

Either you build outbound in-house with the playbook as a blueprint, or you book a discovery call. Either is a win.

Weekly

Tactics from live campaigns

One email per week with a tactical post from a real closed:in campaign. Real numbers, real copy, real lessons.

Who this is for

This isn't theory. It's our actual setup.

closed:in builds outbound engines for B2B SaaS, recruitment firms, PE-backed businesses and agencies. The playbook is the exact pre-launch checklist we run before kicking off a client campaign. We open-source it because (1) the only way to evaluate an outbound partner is by seeing how they think, and (2) most of these mistakes show up in the first 30 days and ruin the next 6 months.

If you build outbound in-house, this gives you the foundation. If you hire an agency, it gives you the questions to ask them.

The B2B outbound playbookfrom a Clay & Instantly partner agency

The infrastructure checklist,broken into 6 chunks.