Agency Client Onboarding SOP: The Deliverability Audit That Prevents Week-3 Fires
Every cold email client should pass through the same technical intake before a single email sends. This SOP catches inherited deliverability problems while they're still the client's problem — not yours.
When an agency takes over a client's cold email, it inherits the client's infrastructure history: their blacklist entries, their damaged domains, their half-configured DNS. The week-3 fire — "campaigns just stopped working" — is almost always a pre-existing condition that a one-hour intake audit would have caught. This is that audit.
Step 1: Inventory everything (30 minutes)
Collect from the client before kickoff:
- Every domain they've ever sent cold email from (including dead ones — history matters)
- Every sending inbox, its age, and its platform (Google Workspace / M365 / SMTP)
- Their ESP/sending tool accounts and current daily volumes
- Bounce and reply rates for the last 90 days, exported
- Their main company domain (which should not be sending cold email — verify)
Step 2: Technical audit per domain (10 minutes each)
Domain audit checklist
- Run the all-inclusive deliverability test — records the warm score, SPF/DKIM/DMARC status, and blacklist standing in one pass
- Blacklist check on the domain AND its sending IPs — log every listing with severity
- MX records — confirm provider, no orphaned entries
- Reverse DNS on dedicated IPs, if any
- Tracking domain — CNAME target, SSL, Cloudflare proxy status
- Redirect behavior — root and www should land on a real site, not a parked page
- Expiry date — flag anything renewing within 90 days
- Placement test from each active inbox — inbox, promotions, or spam per provider
Step 3: Classify the infrastructure
Every domain gets one of three grades, decided by data — not by the client's opinion of it:
- Grade A — usable now. Warm score 80+, clean blacklists, inbox placement confirmed. Can carry campaigns immediately.
- Grade B — usable after fixes. Auth problems, promotions placement, or minor listings. Fixable in 1–2 weeks; keep at reduced volume meanwhile.
- Grade C — retire. Critical blacklists (Spamhaus, SURBL, Barracuda), spam placement across providers, or long abuse history. Do not attempt to rehabilitate on the client's dime — the recovery time calculator shows why: months, with no guarantee.
Step 4: The infrastructure decision
If more than half the client's fleet grades B or C — which is typical for clients who churned off another agency — you have a launch-timeline problem: proper new-domain provisioning plus warmup takes 4+ weeks (see the provisioning SOP).
The standard play is a split build: provision fresh domains for the long term, and bridge the gap with pre-warmed infrastructure so campaigns launch inside the first week. WarmInboxes is the provider we point agencies to for this — pre-warmed inboxes on clean domains, delivered ready to send, which turns a month of onboarding dead-time into days. Clients judge agencies hardest in the first 30 days; launching in week 1 instead of week 5 is often worth more than the entire infrastructure cost.
Step 5: Document and get sign-off
- Deliver a one-page infrastructure report: grades, findings, and the remediation plan
- Get written sign-off on retiring Grade C assets — clients get attached to domains
- Set expectations: volumes, ramp schedule, and the weekly monitoring cadence they'll receive
- Baseline every metric now, so improvement is provable at the 30-day review
The intake audit does two jobs: it prevents inherited fires, and it converts invisible technical work into visible client value. Agencies that skip it end up owning problems they didn't create.
Run the checks first
Before replacing anything, run a free inbox placement test. You might find the issue is DNS, not the domain — and save yourself a week of unnecessary work.