Ruby Experts in Berlin

IOG (IOHK), is one of the world's pre-eminent blockchain infrastructure research and engineering companies.

• Converted a lingering R&D project into a cohesive, production-ready testnet; built and scaled the 35-member engineering team (Core, QA, SRE) to achieve this goal.
• Defined strategic direction and aligned technology development with business objectives as a key member of the leadership.
• Optimized software development processes and implemented agile methodologies, enhancing operational efficiency and code security.
• Delivered projects in a fast-paced startup environment through effective project management and resource allocation.

• Building a cross-functional product team to develop a super app
• Advising and mentoring to support the team and provide input (technical & soft skills)

• Contributed to the architecture design process, leading to scalable and maintainable solutions for complex projects
• Improved app performance through code optimization and implementation of efficient algorithms
• Led a team of iOS developers to complete projects on time and achieve customer satisfaction
• Implemented core design plans into complete iOS app frameworks and delegated project components to corresponding team members
• Key project: City Guide ([link]

• Led 5 cross-functional teams (Product, Engineering, Data, Operations, and Design) across the transportation domain, covering carrier integration, shipment tracking, PUDO, reconciliation, and automation.
• Defined and executed the end-to-end product and integration strategy for 15+ global carriers across Europe and the U.S., ensuring unified APIs.
• Owned the carrier onboarding framework, reducing integration time by 40% through standardization, automation, and improved developer tooling.
• Partnered with major platform customers like Shopify and Wix to analyze EU merchant needs and enhance the shipping and fulfillment experience.
• Led the reconciliation automation initiative, reducing billing discrepancies by 30% and improving invoice validation speed for finance and operations teams.
• Collaborated with data analytics and operations teams to build carrier performance dashboards that improved on-time delivery rates and merchant satisfaction.
• Fostered a strong culture of cross-functional ownership, ensuring seamless collaboration between engineering, product, and external carrier partners.

Enterprise AI content categorization and AI-powered web research.

• Built multi-LLM evaluation framework with annotated data
• Iterated LLM error rates based on annotated datasets
• Implemented AI-powered web research pipeline Stack: LLM, evals, OpenRouter, Python, Node.js, TypeScript, React

• Large-scale B2C legal services platform operating across Europe in air passenger rights and in Germany across labor, mobility, and rental law.
• Owned the end-to-end onboarding and lifecycle foundations of a high-traffic customer acquisition funnel across 8 European markets, supporting ~10,000 new users per month and backed by €100k/month in paid acquisition spend.
• Led the architectural migration of the core intake and decision logic from fragmented legacy flows into a scalable workflow engine, increasing reliability, improving operational efficiency, and enabling faster iteration on funnel performance and user experience.
• Partnered closely with engineering, operations, and commercial stakeholders to optimize activation, manage complex edge cases, and ensure the platform could scale sustainably across markets without compromising performance or consistency.
• Introduced foundational product analytics and performance monitoring to increase visibility into activation, drop-offs, and lifecycle behavior, enabling data-driven prioritization and experimentation.

• Industry: B2B
• Headless frontend with AEM integration
• Key challenge: Migrating a PWA application in live operation based on .NET and legacy code; the entire application must be converted to React and Express.js/TypeScript
• Technical frameworks: Tailwind, XML, JavaScript, Caddy, ReactJS, Express.js, REST API, JSON
• Cloudflare CDN
• Caddy server with GitHub CI/CD pipeline

Led backend engineering across core domains (main backend, notifications, medical knowledge base, results processing), owning delivery quality, team growth, and engineering standards.

Signature Outcomes

Shipped a flexible, no-code membership platform (pricing, packages, duration), enabling commercial changes without engineering involvement and keeping membership tiers coherent over time.

Built a high-impact backend team through mentorship, coaching engineers into independent contributors and establishing onboarding documentation that enabled fast ramp-up.

Scaled the team from 2 → 5 engineers while maintaining delivery cadence and code quality; owned hiring pipelines and onboarding.

Partnered closely with Product during design to assess feasibility, sequence work, and make pragmatic trade-offs between speed, tech debt, and long-term maintainability.

Institutionalized testing and simplicity as defaults, enforcing high test coverage and a “simple-first” architecture approach.

Tech & Practices

Stack: Node.js (TypeScript), Express, PostgreSQL; microservices (Node & Go); event-driven async jobs.

Practices: Testing as a release gate, lightweight design reviews, iterative delivery, documentation-driven onboarding.

Compliance & Security: Led implementation of Privacy Officer recommendations (GDPR and German healthcare regulations).

• Technologies: Ruby on Rails (MVC), JavaScript, CircleCI, Convert, Hotjar, Bugsnag, Git, GitHub, Cursor
• Developed and maintained full-stack features using Ruby on Rails and JavaScript.
• Designed and implemented A/B tests to optimize user experience and product engagement.
• Created and executed RSpec unit and integration tests, ensuring high reliability.
• Contributed to CI/CD pipelines using GitHub Actions to automate deployments.
• Collaborated in cross-functional Agile teams, performed code reviews, and improved application performance and maintainability.

• Led the implementation of a critical backend initiative for the offer teasing feature, resulting in a 10% increase in users actively seeking counter offers.
• Contributed to high-impact features such as instant advice, customer ratings, and automatic contract switching, leading to increased user engagement and conversion rates.
• Built a gRPC service to integrate internal systems with the ERP platform, improving the reliability and observability of data exchange.
• Refactored parts of the legacy Ruby codebase into a more maintainable and scalable Elixir-based architecture.
• Delivered a greenfield project from concept to production on a new stack, integrating with internal services and managing infrastructure setup and deployment.
• Collaborated closely with the front-end team, product managers, and cross-functional team members to ensure the seamless integration of backend features, fostering effective communication and collaboration across disciplines.
• Stack: Ruby, Ruby on Rails, Elixir, OTP, Phoenix, REST, GraphQL, gRPC, PostgreSQL, AWS, Cognito, Lambda, SNS, SQS, Terraform, Helm, Docker, CI/CD, Grafana, Prometheus, Git, Agile Methodology.

• Participated as a public speaker regarding leadership and transformational topics at the WeAreDevelopers World Congress with 15 thousand visitors.

• Backend & API architecture: Independently architected a scalable Node.js backend and RESTful API to handle a high volume of transactions, ensuring robust data management for users, restaurants, and administrators.
• Microservices & infrastructure: Engineered a sophisticated database architecture using PostgreSQL with geographic query optimization. Designed and deployed a robust infrastructure with three separate microservice servers and a database server.
• Performance & scalability: Implemented Redis caching and performed SQL query optimization to improve application performance and reduce load on the database, enhancing responsiveness for real-time services.
• Security & authentication: Integrated secure payment processing via Razorpay and implemented robust middleware for JWT authentication to ensure secure transactions and data integrity.
• CI/CD & deployment: Established a robust CI/CD pipeline using Docker and GitHub Actions for automated and reliable deployment, showcasing fluency in modern DevOps practices.

• Project for mobile users to perform physiotherapy remotely.

• Owning, designing, securing, maintaining reliability of the cloud based platform environments
• Increasing developer productivity and growing the infrastructure team horizontally and vertically to 5 engineers
• Realised infrastructure cost reduction of 50% by utilizing efficient spot instances
• Improved PE developer efficiency by 15% with survey led development process