The Problem: Advising on Tools Meant Finding One They'd Actually Trust

Felix and Penn Frank, brothers and co-founders of Stack Optimize, started by advising companies on outbound tool stacks. “We’d audit setups and recommend changes. But we kept getting asked: ‘What about data? Who should we use?’”

The honest answer was uncomfortable. “Most providers were a gamble. We’d seen clients burn domains with bad data and waste money on recycled lists. We couldn’t confidently recommend anyone.”

When they expanded into running campaigns, the problem got worse. “Now we were responsible for results. If data quality caused a domain flag, that was on us.”

Their own outbound suffered too. “Half our emails bounced. Cold calls hit office lines. We needed one provider we could trust for client campaigns AND our own pipeline.”

The Fix: One Data Provider for Everything

Felix and Penn found Prospeo while evaluating tools for a client. “We tested it against five providers. Bounce rates, mobile accuracy, catch-all handling. Prospeo won on everything that mattered.”

• Client campaigns they could stand behind: “Deliverability hit 94%+ across our client book. Bounce rates under 3%. Domain flags stopped happening.”
• Data they'd stake their reputation on: “We recommend tools for a living. Prospeo became our default because we use it ourselves. That’s the strongest endorsement we can give.”
• Their own outbound finally worked: “Verified emails, direct mobiles, fast list building. Our pipeline grew alongside client results.”

The Results: $1M ARR, 7 Employees, Zero Domain Burns

Client performance:

• Deliverability: 94%+ average
• Bounce rate: under 3%
• Domain flags: zero across all clients
• Agency growth: Revenue: $0 → $1M ARR; Team: Co-founders → 7 employees; Data stack: Consolidated to one trusted source
• “We built a million-dollar agency on data we trust,” Felix says. “Client campaigns perform. Our own outbound performs. We hired 7 people to support growth that came from consistent results.”
• “Domain protection sounds boring until a client churns because their emails hit spam for three months. We don’t have those conversations anymore,” Penn adds.

What’s Next

Stack Optimize is scaling both sides. “We’re adding campaign clients confidently. The infrastructure handles volume without quality dropping.”

Felix’s advice: “Find a data provider you’d use for your own outbound, not just client work. We built to $1M ARR because Prospeo worked for both. That alignment is how you scale.”