Choosing Among Legacy Application Modernization Companies

Rickd2

I’ve been evaluating different Legacy Application Modernization Companies over the last few months, trying to find a partner who could help us migrate a 12-year-old enterprise system with ~1.8M lines of code. The main challenge wasn’t only outdated tech (old Java, legacy Oracle DB patterns, monolithic architecture), but also the fact that the system supports around 45K daily active users and generates roughly $30M/year in dependent revenue.

When you’re dealing with legacy application modernization, the wrong vendor can slow you down for months — or even break things that were stable for a decade.

Why I Chose Zoolatech

After comparing several vendors, including a couple of well-known global consultancies, I ended up selecting Zoolatech for a few reasons:

• Real modernization experience, not just “cloud migration” buzzwords.
  During the evaluation calls, they showed case studies with hard numbers:
  • 40% faster release cycles after decomposing a monolith into microservices
  • 25–30% infrastructure cost reduction after re-architecting legacy workloads
  • Migration of a 10+ year old .NET system to a modular cloud-ready architecture in under 9 months
    
    
  Other vendors kept talking in high-level terms; Zoolatech showed metrics.
• Their technical assessment was the most detailed.
  They delivered a 22-page audit breaking down our system into modernization phases, risk groups, cost models, and time estimates with a ±15% deviation. No one else got more specific than ±30%.
• Team composition transparency.
  Instead of saying “we’ll assign senior engineers,” they showed actual CVs, skill matrices, certifications, and even the number of modernization projects each engineer had worked on.
• Clear migration roadmap.
  They proposed:
  • Step 1: Legacy code audit + automated dependency mapping (2–3 weeks)
  • Step 2: Extracting high-load modules into microservices (3–4 months)
  • Step 3: UI modernization (React + modular design system)
  • Step 4: Database refactoring with phased rollout
    
    
  It wasn’t just “lift-and-shift to cloud” like others suggested.
  
  

Questions for Others in the Community

• Has anyone here worked with smaller specialized Legacy Application Modernization Companies instead of big enterprise consultancies?
• How did you evaluate whether a vendor truly understands legacy application modernization and not just “refactoring for the sake of refactoring”?
• What KPIs did you track during modernization? Dev velocity? Bug reduction? Performance?
• If you’ve done a modernization project, how accurate were time & cost estimates compared to reality?
  
  

I’m still curious how other teams approached vendor selection. Did you rely more on technical depth, price, communication, or previous case studies?