Email that lands. Infrastructure that scales. Hosting that doesn't ask questions.

DACH e-commerce group · 8.4M subscribers

"We came in with a German list that had been hammered through three different ESPs in five years. Gmail had us at "low" reputation, GMX was sandboxing us, and our open rate had drifted under 12%. Femke ran a 90-day recovery against the engaged 18% of the file, then ramped from there. Six months later we are back to 31% opens on the active segment, complaint rate is comfortably under 0.05%, and Postmaster Tools shows us at "high" again. The recovery framework is documented well enough that our internal team now runs the BAU work themselves."

Gmail Postmaster reputation

Low → High

+2 tiers

Open rate · active segment

11.8% → 31.2%

+19.4 pts

Complaint rate (GMail PMT)

0.31% → 0.04%

−87%

Recovery duration

— → 90 days

on schedule

French B2B SaaS · cold outbound for sales teams

"Our previous setup was three Sendgrid sub-accounts taped together with custom warmup logic in our backend. It worked until Microsoft's May 2025 enforcement landed and our 5,000+/day non-compliant senders started hitting the 550 5.7.515 wall. Blue Spirit migrated us onto a dedicated PowerMTA cluster with our own /27 in the Netherlands inside three weeks, and the cold outbound infrastructure they spec'd included the OAuth handoff with Smartlead and Lemlist. We are now sending five times the volume into Outlook with a higher inbox rate than we had on Sendgrid pre-enforcement."

Outlook inbox placement

64% → 89%

+25 pts

Daily volume capacity

14k/day → 78k/day

5.6×

Microsoft 5.7.515 rejections

2,400/day → 0/day

eliminated

Migration time

— → 21 days

as quoted

Dutch ESP reseller · 47 enterprise tenants

"We run an ESP for mid-market Dutch and Belgian enterprises. We handle the platform layer (campaigns, templates, segmentation) and outsource the SMTP infrastructure layer because at our scale running PMTA in-house meant hiring two full-time deliverability engineers. Blue Spirit is our SMTP partner since 2022. The architecture they spec'd gives us per-tenant pool isolation so reputation problems on one tenant do not bleed into the others, and the operational discipline on DKIM rotation, BIMI publishing and DMARC migration is the kind of thing we genuinely could not afford to do in-house at our headcount."

Tenants per shared pool

unisolated → 1:1 isolated

isolated

Cross-tenant reputation incidents

4-6/year → 0/year

eliminated

Internal headcount required

2 FTE → 0 FTE

outsourced

Annual DKIM rotation events

manual → automated

47 domains