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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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Company & 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.

Frequently asked questions

What did Alex Devero do at Persoo?

Alex joined Persoo as a frontend developer and later became a co-founder. He rebuilt the search widget and recommendation carousels with modern JavaScript, removed jQuery, formalised implementation practices, mentored the team, and contributed to product strategy.

Was Alex Devero a co-founder of Persoo?

Yes. Alex joined as a frontend developer and, after about two years, became an officially registered co-founder, helping shape product direction until he sold his share on leaving.

What was the outcome of the Persoo project?

Faster, more reliable search and recommendation UIs, a modern jQuery-free codebase, reduced delivery time, and a stronger team. Persoo was later acquired by Luigi’s Box in a multi-million-euro deal in early 2024.

What technologies were used on the Persoo project?

JavaScript (ES6+), HTML, and CSS — migrating away from a legacy jQuery stack.
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