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Evolving Persoo: From Integration to Leadership in Personalized E-Commerce

Custom JavaScript widget revamps, UI modernization, and team leadership that scaled delivery and set the company's product vision.

Role: Frontend Developer → Co-FounderDuration: 26 monthsStack: JavaScript (ES6+), HTML, CSS

Quick Results

  • Rebuilt search widget for performance & accuracy
  • Developed responsive, customizable recommendation carousels
  • Eliminated jQuery → modern JavaScript stack
  • Reduced project delivery time via refactored workflows
  • Led and mentored team to level up implementation standards
  • Influenced product strategy as co-founder
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Client & Context

Persoo, a Czech e-commerce startup offering behavior-based search, recommendations, and dynamic upsell/cross-sell tools, needed us to elevate its client integrations and product reliability. I joined as a frontend developer, later becoming a co-founder and contributing strategically.

Challenges / Constraints

  • Legacy widgets slowed load times and were not responsive
  • Implementation workflows were slow and inconsistent
  • UI depended on jQuery, limiting flexibility
  • No team codified best practices or modern standards

Approach

  • Rewrote the search widget using modern JS for performance and search accuracy
  • Redeveloped recommendation carousels to be responsive and easily stylable per client
  • Removed jQuery—migrated to vanilla and ES6 patterns
  • Formalized onboarding and implementation practices; mentored junior developers
  • Collaborated cross-functionally in product strategy and roadmap definition

Results

  • Performance Improved: Search and carousel UIs load faster and are more reliable
  • Deployment Accelerated: Workflow efficiency reduced delivery time
  • Modern Codebase: Scalable, maintainable code without legacy dependencies
  • Stronger Team: Onboarded and guided high-performing implementation developers
  • Strategic Impact: As co-founder, shaped product direction and growth

Learnings

  • Balance between building and leading—mentoring engineers while owning delivery
  • Modern JS transformation allows performance and agility gains
  • Developer advocacy in product decisions yields better alignment and execution

Aftermath

Persoo was acquired by Slovak competitor Luigi’s Box in a multi‑million‑euro deal in early 2024, consolidating their position as the leader in search optimization across the Czech and Slovak markets.
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