Customer engagements
Case studies
Anonymised but technically faithful walkthroughs of recent customer engagements. Every recovery, migration and reputation rebuild includes the diagnostic phase, the operational decisions, and the per-receiver outcome data.
- EU · E-commerce / Retail
How a DACH retail group recovered Gmail reputation after three ESP migrations
A 90-day engaged-segment recovery against an 8.4M-subscriber list with three years of accumulated reputation drift across Sendgrid, Mailchimp Transactional and an in-house Postfix relay.
- Gmail Postmaster reputation
- Low → High
- +2 tiers
- Active-segment open rate
- 11.8% → 31.2%
- +19.4 pts
90-day Gmail reputation recovery + ongoing managed deliverability 9mo - EU · B2B SaaS / Cold outbound
Surviving Microsoft's May 2025 enforcement: a 21-day cold-outbound infrastructure rebuild
When Microsoft's 5,000-emails-per-day non-compliant-sender enforcement landed, this French B2B SaaS had three weeks to rebuild their entire outbound stack or lose 60% of their outbound capacity overnight.
- Outlook inbox placement
- 64% → 89%
- +25 pts
- Daily volume capacity
- 14k → 78k
- 5.6×
21-day Sendgrid → dedicated PMTA migration after Microsoft 5.7.515 enforcement 12mo - EU · ESP / Reseller
How a Dutch ESP reseller scaled to 47 enterprise tenants without two FTE deliverability hires
A 4-year partnership covering per-tenant pool isolation, cross-tenant reputation containment, and the operational discipline that made running 47 enterprise outbound flows on shared infrastructure economically viable.
- Tenants on shared infrastructure
- 47 isolated
- pool-per-tenant
- Cross-tenant reputation incidents
- 0/year
- −100%
Multi-tenant SMTP infrastructure outsourcing · 4-year ongoing partnership 48mo
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