Bogdan Bak - Senior Full Stack Engineer

Q: Where is Bogdan based?

Bogdan is based in Warsaw, Poland .

Q: What languages does Bogdan speak?

Bogdan speaks the following languages: English (Advanced), Dutch (Advanced), Polish (Advanced) .

Q: How many years of experience does Bogdan have?

Bogdan has at least 10 years of experience. During this time, Bogdan has worked in at least 3 different roles and for 3 different companies . The average length of individual experience is 4 years and 6 months . Note that Bogdan may not have shared all experience and actually has more experience.

Q: What is Bogdan's latest experience?

Bogdan's most recent position is Senior Full Stack Engineer at Makolab .

Q: What companies has Bogdan worked for in recent years?

In recent years, Bogdan has worked for Makolab and IXOPAY .

Q: Which industries is Bogdan most experienced in?

Bogdan is most experienced in industries like Information Technology , Retail , and Healthcare . Bogdan also has some experience in Tourism and Banking and Finance .

Q: Which business areas is Bogdan most experienced in?

Bogdan is most experienced in business areas like Information Technology , Product Development , and Quality Assurance .

Q: Which industries has Bogdan worked in recently?

Bogdan has recently worked in industries like Information Technology , Retail , and Banking and Finance .

Q: Which business areas has Bogdan worked in recently?

Bogdan has recently worked in business areas like Information Technology , Product Development , and Quality Assurance .

Recommended expert

Warsaw, Poland

Experience

Mar 2022 - Present

4 years 1 month

Warsaw, Poland

Senior Full Stack Engineer

Makolab

Led architecture for a multi-tenant eCommerce SaaS that powers branded storefronts and headless experiences across regions.
Defined service boundaries and interfaces while migrating microservices from Ruby on Rails to Node.js (NestJS), reducing cold-start latency and simplifying deployment pipelines.
Built new React and Next.js frontends with server-side rendering and static generation; improved Core Web Vitals and decreased LCP by double-digit percentages.
Delivered Shopify embedded app integrations using OAuth, App Bridge, Polaris UI, and webhooks for orders, inventory, and fulfillment.
Implemented WordPress as content hub (headless mode), exposing GraphQL and REST endpoints consumed by Next.js storefronts.
Designed internal GraphQL gateway and versioned REST APIs with OpenAPI, enabling partner integrations and third-party marketplaces.
Introduced AI features: product recommendation service and semantic search using Python (FastAPI) plus vector search; integrated OpenAI for copy suggestions, FAQs, and support triage.
Wrote small utilities in Go for log processing and concurrent sitemap generation to speed up SEO jobs.
Shipped mobile features with React Native, reusing TypeScript business logic and API clients from web packages.
Implemented background processing with Sidekiq (Rails legacy) and BullMQ (Node), including idempotency keys and dead-letter queues.
Built real-time order status channels with WebSockets and server-sent events to keep dashboards and kiosks in sync.
Hardened security: OAuth 2.0, OIDC, signed webhooks, HMAC validation, rate limiting, secrets rotation on AWS Secrets Manager.
Owned CI/CD on GitHub Actions and GitLab CI: multi-stage Docker builds, preview environments, Terraform modules, and automated schema checks.
Established testing strategy: unit tests (Jest, RSpec), component tests (React Testing Library), end-to-end (Cypress), and contract tests (Pact) between services.
Tuned PostgreSQL and Redis caching; created read models and projections for analytics; added ElasticSearch for catalog faceting.
Set up observability: Prometheus metrics, Datadog traces, structured logs, error budgets, and SLO dashboards for critical endpoints.
Collaborated with product, design, and merchants; translated requirements into technical roadmaps and capacity plans.
Mentored engineers on code reviews, API consistency, performance profiling, and incident response.

Jul 2019 - Feb 2022

2 years 8 months

Warsaw, Poland

Full-Stack Engineer

IXOPAY

Contributed to a fintech transaction platform focused on high throughput, reliability, and compliance.
Migrated customer-facing frontend from Angular to React, introducing TypeScript, hooks, and shared UI kits.
Built Node.js microservices for transaction routing, settlement exports, and provider webhooks; integrated Laravel and Ruby on Rails legacy endpoints during the transition.
Implemented real-time notifications for payment status with WebSockets and server-sent events, improving operations dashboards.
Added AI/ML components in Python for anomaly and fraud detection; produced features from transaction graphs and trained baseline models to alert risk teams.
Designed idempotent webhooks and reconciliation jobs; improved data quality and rerun safety for payment providers.
Tuned PostgreSQL indices, optimized Redis patterns for ephemeral state, and reduced P95 latencies across several APIs.
Automated deployments on AWS (ECS, Lambda, API Gateway, S3) with infrastructure as code and blue-green rollouts.
Strengthened authentication and authorization flows with OAuth 2.0 and JSONWeb Tokens; added audit trails.
Expanded test coverage with Jest, Cypress, and Postman collections; added health checks, circuit breakers, and dashboards for on-call.

Oct 2015 - Jun 2019

3 years 9 months

Delft, Netherlands

Web Developer

Fabrique

Built healthcare and hospitality web projects from greenfield to launch with WordPress, Shopify, Ruby, and SQL backends.
Developed responsive frontend features and pages in React and vanilla JavaScript; implemented accessible components and forms.
Created backend endpoints for bookings, patient content workflows, and inventory; integrated with external APIs for payments and email.
Wrote custom Shopify themes and Liquid sections; synchronized catalog and pricing with back-office systems via Admin API.
Implemented search and faceting with ElasticSearch; added server-side caching and HTTP caching strategies.
Optimized database queries with proper indexing and pagination; reduced heavy endpoints’ response times.
Added automated tests with PHPUnit and Jest; established basic CI pipelines for builds and linting.
Collaborated with designers and editors to ship performance-focused pages and content workflows.

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Retail, Healthcare, Tourism, and Banking and Finance.

Information Technology

Retail

Healthcare

Tourism

Banking and Finance

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, and Quality Assurance.

Information Technology

Product Development

Quality Assurance

Summary

Senior Full-Stack Software Engineer specializing in Ruby on Rails, Node.js, React, and Shopify applications. 10 years experience building eCommerce, fintech, and SaaS platforms end-to-end, from architecture and microservices to polished frontends and CI/CD in the cloud. Comfortable leading squads, designing APIs, and shipping reliable features with automated tests. Hands-on with AI and machine learning integrations for recommendations, search, and fraud detection. Strong DevOps mindset on Amazon Web Services with infrastructure as code, observability, and cost awareness. Passionate about clean code, performance, and developer experience.

Skills

Frontend: React, Next.js, Redux/zustand, React Query, React Native, Typescript/javascript, Html5, Css3, Scss, Tailwind Css, Material Ui, Shopify, Liquid, Webpack, Vite, Storybook, Accessibility/web Vitals, Wordpress
Backend: Ruby On Rails, Php (Laravel), Node.js (Express, Nestjs), Graphql, Rest Api Design, Webhooks, Grpc, Websockets, Server-sent Events, Sidekiq, Bullmq, Event-driven And Microservices Patterns, Domain-driven Design, Oauth 2.0, Openid Connect, Jsonweb Tokens
Databases: Postgresql, Mysql, Mongodb, Redis, Elasticsearch, Sqlite, Kafka/rabbitmq
Ai & Data: Python (Fastapi, Scikit-learn), Openai Api, Vector Search (Faiss, Pinecone), Embeddings And Rag Patterns, Golang
Devops & Tools: Aws (Ecs, Eks, Lambda, Api Gateway, S3, Cloudfront, Rds, Dynamodb, Cloudwatch), Docker, Kubernetes, Terraform, Github Actions, Gitlab Ci, Jenkins, Argo Cd, Feature Flags, Launchdarkly, Prometheus, Grafana, Datadog, Sentry
Testing & Quality: Rspec, Minitest, Jest, React Testing Library, Cypress, Playwright, Pact, Testcontainers, Postman, Tdd/ci-gated Quality Thresholds

Languages

English

Advanced

Dutch

Advanced

Polish

Advanced

Education

Sep 2012 - Jul 2015

Delft University of Technology

Bachelor of Computer Science · Computer Science · Delft, Netherlands

Statistics

Experience

Total positions 3

Experience in Information Technology 4 y

Avg length 3 y 5 m

Longest experience 4 y

Global Experience

Countries worked in 2 (Poland, Netherlands)

Primary country Poland

Expertise

Recent roles Senior Full Stack Engineer, Full-Stack Engineer, Web Developer

Main industries Information Technology, Retail, Healthcare

Main business areas Information Technology, Product Development, Quality Assurance

Qualifications

Highest degree Bachelor

Profile

Created

November 2025

Last Update

January 2026

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Bogdan based?

Bogdan is based in Warsaw, Poland.

What languages does Bogdan speak?

Bogdan speaks the following languages: English (Advanced), Dutch (Advanced), Polish (Advanced).

How many years of experience does Bogdan have?

Bogdan has at least 10 years of experience. During this time, Bogdan has worked in at least 3 different roles and for 3 different companies. The average length of individual experience is 4 years and 6 months. Note that Bogdan may not have shared all experience and actually has more experience.

What roles would Bogdan be best suited for?

Based on recent experience, Bogdan would be well-suited for roles such as: Senior Full Stack Engineer, Full-Stack Engineer, Web Developer.

What is Bogdan's latest experience?

Bogdan's most recent position is Senior Full Stack Engineer at Makolab.

What companies has Bogdan worked for in recent years?

In recent years, Bogdan has worked for Makolab and IXOPAY.

Which industries is Bogdan most experienced in?

Bogdan is most experienced in industries like Information Technology, Retail, and Healthcare. Bogdan also has some experience in Tourism and Banking and Finance.

Which business areas is Bogdan most experienced in?

Bogdan is most experienced in business areas like Information Technology, Product Development, and Quality Assurance.

Which industries has Bogdan worked in recently?

Bogdan has recently worked in industries like Information Technology, Retail, and Banking and Finance.

Which business areas has Bogdan worked in recently?

Bogdan has recently worked in business areas like Information Technology, Product Development, and Quality Assurance.

What is Bogdan's education?

Bogdan holds a Bachelor in Computer Science from Delft University of Technology.

What is the availability of Bogdan?

Bogdan is immediately available full-time for suitable projects.

What is the rate of Bogdan?

Bogdan's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.