Petar R.

SparkLoop is a recommendation and partner-monetization platform for newsletter creators, operating as part of Kit (formerly ConvertKit) in the creator economy.

• Built the end-to-end payment processing pipeline, invoicing customers and paying out partners with precision across complex multi-source affiliate datasets
• Designed an email tracking and analytics system to counter Apple MPP’s industry-wide disruption of open tracking, using a custom tracking pixel and bot-detection algorithms for accurate open and click attribution
• Reduced main application RPM load via Cloudflare Workers, caching critical data at the edge and geo-optimizing real-time delivery for third-party integrations
• Shipped dozens of features across Rails, PostgreSQL (1TB+), Elasticsearch, and ClickHouse, integrating 20+ partner APIs

Allora Software is an independent software studio building web applications and consulting on Rails architecture, API integrations, and product development.

• Shipped an Automotive Import Cost Calculator, automating customs, tax, and logistics calculations for European vehicle importers
• Built an influencer marketing platform end-to-end using Rails 7, Hotwire/Turbo, Stimulus.js, and TailwindCSS
• Delivered a startup perks and benefits system, handling architecture, integrations, and frontend layers
• Advised clients on Rails architecture decisions, API integration strategy, and pragmatic product development
• Operated as the sole engineer across discovery, scoping, and delivery phases for multiple long-running engagements

• Tarmac.io is a full-service software development studio delivering custom web applications for clients across multiple industries
• Shipped approximately 25 new product features per year as a core full-stack developer across diverse client engagements
• Reduced rework by 20% through a rigorous TDD approach, improving release predictability and code stability
• Reduced application costs by 15–35% through CI/CD pipeline optimization and infrastructure tuning
• Maintained consistently high user experience scores across all delivered projects through structured QA practices
• Contributed to architecture and code review processes, raising delivery standards across the engineering team

Personal Programmer is an automotive-sector startup applying machine learning algorithms to identify high-margin used vehicles in real time.

• Built ML-driven detection logic identifying used cars with the highest profit margins in sub-second response times

• Developed software solutions addressing operational and pricing challenges across multiple parties in the automotive sector

• Helped scale the platform from a single-region startup to a trusted solution across three European markets

• Contributed to data pipeline architecture and integration layers powering real-time vehicle valuation

FrontWise Group is a software services company delivering custom platforms across web and learning-technology domains.

• Joined as outsourced developer to support delivery of a web-based learning platform under tight deadline

• Implemented backend features and integrations to meet platform launch milestones

• Coordinated with the in-house team to align on architecture and shipping priorities

• Closed delivery gaps that allowed the project to ship on schedule

• Earned Top-rated status by consistently delivering custom web applications across dozens of client engagements

• Applied critical thinking to scope problems, evaluate solutions, and make decisions on behalf of clients

• Served clients efficiently across multiple time zones with structured delivery processes

• Built reusable Rails components and patterns reused across multiple engagements to accelerate delivery