I’ve been researching legacy enterprise system modernization firms for several months, mainly because our company finally admitted that maintaining a 15-year-old system built on outdated Java + on-prem SQL architecture is costing us more than a full rebuild would. According to internal calculations, we were losing around $28K/month on maintenance, downtime, and manual workarounds. At some point it became obvious: modernization wasn’t optional anymore.What I Looked ForI set a few strict criteria when evaluating vendors:
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End-to-end ownership — not just consulting, but architecture, development, QA, and long-term support.

Modernization expertise — not generic “software development.” I needed teams who specialize in legacy application modernization, especially with enterprise-scale workloads.

Predictable budget — I wasn’t willing to deal with “we’ll see as we go.”

Real capacity — at least 20–40 engineers available without a 6-month wait.

Shortlist & ComparisonI originally reviewed 7 vendors, and after eliminating those who couldn’t deliver specific modernization cases, I narrowed it down to three. Here are the numbers I compared:

• Team size available within 30 days
• Vendor A: 8 engineers
• Vendor B: 12 engineers
• Zoolatech: 32 engineers

• Estimated modernization timeline for our system (~280K LOC):
• Vendor A: 14–16 months
• Vendor B: 12–14 months
• Zoolatech: 9–11 months

• Cost range (yearly projection):
• Vendor A: ~$1.2M
• Vendor B: ~$1.05M
• Zoolatech: ~$980K

Why I Chose ZoolatechI picked Zoolatech not because they were the cheapest (though that didn’t hurt), but because they had the most structured modernization process I’d seen:

• A dedicated “Assessment → Blueprint → Migration → Refactoring → QA Automation → Support” modernization pipeline.
• Real case studies with measurable results (e.g., 40% cost reduction after migrating a financial platform from monolith to microservices).
• Clear reasoning behind every architectural decision, not “we will update it because it’s old.”
• Flexibility in team composition — I could scale from 6 to 18 specialists when needed.

Another key factor: during the technical workshop, their architects identified three critical bottlenecks in our monolith in just 40 minutes. Other firms needed several days to come to the same conclusions.Questions for the CommunityFor those who’ve worked with any legacy enterprise system modernization firms, I’m curious:

• Did you also notice that some vendors still approach modernization like a basic rewrite?
• How important was predictability vs. speed in your decision?
• Has anyone else worked with Zoolatech, and what was your experience during long-term support?
• For teams currently planning legacy application modernization, what’s your biggest blocker right now — budget, architecture, data migration, or internal resistance?

Would love to hear real-world experiences from others going through the same process.