Chris Hasiński
Verified Expert in Engineering
Software Engineer and Developer
Poznań, Poland
Toptal member since October 2, 2024
Chris is a back-end engineer specializing in Ruby and Ruby on Rails application performance. Known for optimizing sluggish systems, he excels in databases, caching, and scaling high-traffic applications. Although his primary focus is on these areas, Chris is adept at tackling a variety of technical challenges. With a keen eye for detail, he consistently ensures robust and efficient system performance.
Portfolio
Experience
- Databases - 17 years
- Linux - 17 years
- SQL - 16 years
- MySQL - 13 years
- PostgreSQL - 10 years
- Ruby Performance - 8 years
- Ruby on Rails (RoR) - 8 years
- Ruby - 8 years
Availability
Preferred Environment
Linux, MacOS, RubyMine, Ruby, Ruby on Rails (RoR), PostgreSQL, REST APIs
The most amazing...
...thing I've worked on involved resolving blockers during due diligence for a startup acquisition by a Fortune 500 company.
Work Experience
Senior Software Engineer
SilkFred
- Reduced core endpoint latency by 50%, leading to a much snappier user experience and lower hosting costs.
- Reduced average build time by an order of magnitude, improving developer experience.
- Built a voucher refund system, which led to a significant improvement in refund rates.
Senior Software Engineer
Mooncard
- Oversaw multiple initiatives to rework critical components of the administration panel for a large-scale banking app.
- Integrated components with multiple external systems to manage user data efficiently.
- Implemented a security assertion markup language (SAML) based authentication solution for enterprise customers.
Senior Back-end Engineer
Equinix
- Headed a team that resolved all blockers during the due diligence process for Packet Inc., facilitating their acquisition by Equinix.
- Resolved database locking issues preventing provisioning servers' scaling up, a core feature for Packet.
- Increased build speed by over 60%, resulting in faster product iterations and a 30% reduction in development infrastructure costs.
Senior Software Engineer
Accounto
- Integrated payments into the accounting system, syncing with the Swiss banking system.
- Reworked the deployment system for a large microservice-based codebase, resulting in safer and atomic deployments.
- Standardized the API, enabling the front-end team to regain lost velocity and deliver features much faster.
Senior Software Engineer
Toptal
- Reworked the skill search functionality for this website, incorporating full-text search capabilities.
- Developed the headless content management system (CMS) that powers Toptal's blogs.
- Enhanced the developer experience by reducing build times.
Senior Back-end Engineer
Loot
- Designed and implemented a complete banking application in less than four months.
- Integrated 3rd-party know-your-customer (KYC) and anti-money laundering (AML) solutions, along with tools for customer support.
- Migrated the payment provider, ensuring no interruption to transactions or end-user operations.
Senior Software Engineer
Espeo Software
- Spearheaded and released over half a dozen products using various technology stacks.
- Conducted over a hundred job interviews for engineering candidates.
- Collaborated with clients on new project estimations and scoping.
Research Scholar
University of California, Davis
- Led the data processing for the CASP9 protein folding experiment.
- Managed twenty data processing servers, overseeing regular maintenance and coordinating workloads.
- Developed several protein folding comparison applications.
Experience
Equinix Deploy
https://deploy.equinix.com/Education
Coursework Toward Master's Degree in Data Processing Technologies
Poznań University of Technology - Poznań, Poland
Bachelor's Degree in Computer Science
Poznań University of Technology - Poznań, Poland
Skills
Libraries/APIs
REST APIs, Graphiti, React
Tools
RubyMine, Open Neural Network Exchange (ONNX)
Languages
Ruby, C, C++, SQL, Java, JavaScript, PHP, Perl, Fortran, Python
Frameworks
Ruby on Rails (RoR), Symfony, Grape, Angular
Storage
Databases, PostgreSQL, MySQL, Elasticsearch, Redis, MongoDB
Platforms
Linux, MacOS, Amazon Web Services (AWS), Oracle, AWS Lambda
Paradigms
Microservices
Other
Ruby Performance, API Integration, Web Development, Algorithms, Machine Learning, Retrieval-augmented Generation (RAG), Vector Databases, Data Structures, Liferay, AI Agents
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