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Serhii Tsapko
Senior Full Stack Software Engineer
Krakow, Poland | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | Available for B2B
contracts in Poland

SUMMARY
Senior Full Stack Software Engineer with 15+ years of experience building enterprise SaaS platforms, custom
e-commerce systems and business-oriented web applications. Specialized in PHP/Laravel ecosystems, Vue.js
applications, REST API and GraphQL integrations, MongoDB-backed systems, SSR/SPA architectures and
performance optimization. For 4 years developed, maintained and extended enterprise applications for Idomoo
— including scene editors and storyboard builder interfaces built with Vue.js and AngularJS, PHP/MongoDB
and Node.js backend services, AWS infrastructure and Samsung VXT solutions. Reduced API response
payload from 15MB to under 3MB and optimized complex backend operations from ~2 minutes to 20–30
seconds through MongoDB query and data-processing improvements. Increased SEO-driven traffic from 170 to
1,400 daily visitors within 9 months for a business platform operating in a highly competitive procurement niche.

TECH STACK
Core: PHP, Laravel, JavaScript, Vue.js, AngularJS, MySQL, MongoDB, REST API, GraphQL
Additional: React, Node.js, Apollo Server, Vite, SSR/SPA, Inertia.js, TailwindCSS, Redis
Infrastructure & DevOps: AWS (S3, SES, Cognito, Lambda), Docker, Git, Nginx, Laravel Forge
Integrations: Stripe, LiqPay, HubSpot, Mailgun
SEO & Performance: SSR architecture, Core Web Vitals, performance optimization, semantic HTML,
structured data, crawlability

PROFESSIONAL EXPERIENCE
Senior Full Stack Software Engineer May 2022 – May 2026
dias.team — outsourced to Idomoo, Israel
Worked across 6 enterprise web applications within Idomoo's platform ecosystem, focusing on editor interfaces,
backend optimization and media workflow tools.
– Reduced API response payload from up to 15MB to under 3MB by optimizing MongoDB aggregations,
filtering over-fetched data and eliminating redundant nested queries
– Cut complex backend request times from ~2 minutes to 20–30 seconds, and medium-complexity requests
from 5–10 seconds to 2–3 seconds
– Rebuilt virtual file manager: replaced filesystem-based tree traversal with MongoDB metadata hierarchy
and AWS S3 storage, reducing folder load time from ~10 seconds to 2–4 seconds
– Migrated 2 platform tools from vue-cli to Vite and Vuex to Pinia, resolving reactivity issues and restoring
broken functionality
– Developed and maintained SPA applications and complex editor interfaces using Vue.js and AngularJS —
new features, bug fixing and performance improvements
– Worked with GraphQL/Apollo backend services and Node.js using Apollo Server and MongoDB — bug
fixing, extending existing functionality and implementing new features
– Worked with AWS services: S3 and SES integration on frontend and backend; resolved issues and
improved workflows with Cognito and Lambda
– Developed Samsung VXT / PIRS applications and configured enterprise video player solutions

Senior Web Developer & SEO Specialist Feb 2015 – May 2022
Business Consulting Groups, Kazakhstan
Full-cycle development and SEO-driven growth of business web platforms and procurement systems for the
Kazakhstan market. Managed up to 3 projects in parallel.
– Grew organic search traffic 8x — from 170 to 1,400 daily visitors within 9 months
– Achieved TOP-2 rankings in Kazakhstan's public procurement niche for highly competitive search queries
– Built SSR web architectures with long-term organic growth strategy: semantic markup, Core Web Vitals,
crawlability, structured data
– Led technical planning, performance optimization and full-stack development of business-oriented web
platforms
Founder & Technical Lead Feb 2010 – Dec 2014
Webizon, Ukraine
Founded and led a web development studio of 7 engineers delivering custom CMS platforms, e-commerce
systems and client web applications.
– Built and led a team of 7 developers; full hiring, technical direction and project delivery responsibility
– Developed multiple custom PHP-based CMS platforms from scratch
– Delivered e-commerce solutions with Stripe, LiqPay and Platon payment integrations
– Developed SEO-oriented web projects with SSR architecture and performance optimization from day one

FREELANCE WEB DEVELOPMENT & SEO
Independent Practice 2010 – 2022
Delivered 400+ websites across various niches alongside main roles — landing pages, corporate sites, product
catalogs and e-commerce stores. Applied SEO-oriented architecture from day one: SSR where needed,
semantic markup, Core Web Vitals awareness, crawlability planning and structured data.

SELECTED PROJECTS
reflect-on.de Laravel · Vue.js · Inertia.js · Stripe · MySQL
Coaching and resilience SaaS platform for the German market. Multi-application Laravel architecture featuring
SSR public website, two SPA applications (Vue.js + Inertia.js), Stripe payment integration, user dashboard,
administration panel, course management and automated PDF certificate generation with custom design
selection.
rona.ua PHP · Twig · MySQL · JavaScript
Large-scale e-commerce platform built from scratch. Custom CMS architecture with catalog and product
management (20,000+ SKUs), order processing workflows, payment integrations, ERP integration and
automated marketplace exports.

EDUCATION
Sumy State University
Electronic Systems Engineering, 2005 – 2010

LANGUAGES
Ukrainian, Russian — Native
English — Pre-Intermediate (written)
Polish — Elementary