Szymon Fiedler
Senior Software Engineer at Arkency
Swarzędz, Greater Poland Voivodeship
Summary
🤩
Rockstar🎓
Top SchoolSzymon Fiedler is a Senior Software Engineer with 15+ years building high-stakes systems where money, compliance and legacy code collide. He designs and modernizes payment and financial platforms—having built a PCI DSS Level 1 gateway and shaped invoicing, reconciliation and insurtech systems auditors trust—while also solving traffic-spike and inventory-concurrency problems for high-scale commerce. A Domain-Driven Design practitioner and Rails Event Store maintainer, he brings event-sourcing expertise and a careful, systems-level mindset to gradual legacy transformations. Since 2014 he's delivered critical, remote-first projects through Arkency and multiplied impact as a coach and conference co-organizer. His open-source contributions to devise_security_extension and rails_event_store reflect deep attention to security, metadata handling and testability—practical strengths that surface long before problems become crises.
15 years of coding experience
6 years of employment as a software developer
Master Physics Applied Computer Science, Master Physics Applied Computer Science at Uniwersytet im. Adama Mickiewicza w PoznaniuMaths Physics IT, Maths Physics IT at XXXII Liceum Ogólnokształcące im. H. Cegielskiego w Poznaniu
Polish, English, German
Github Skills (15)
ruby10
security10
rspec10
event-driven-architecture10
user-authentication10
authentication10
devise10
password-manager10
cqrs10
event-sourcing10
1password10
password-vault10
rails9
ruby-rails9
software-design8
Programming languages (3)
Github contributions (5)
RailsEventStore/rails_event_store
Oct 2016 - Jan 2023
A Ruby implementation of an Event Store based on Active Record
Role in this project:
Back-end Developer
Back-end DeveloperContributions:8 releases, 8 reviews, 296 commits in 6 years 4 months
Contributions summary:Szymon primarily focused on refactoring the event store implementation, dropping a wrapper around event metadata to address key naming conflicts. Their work involved modifying specification tests and actions related to reading streams, indicating a deep understanding of the event store's internal workings. They also made contributions to the testing infrastructure, including the addition of matchers for events, data, and metadata, enhancing the testing capabilities for the project.
dddevent-sourcingrailsaggregate-rootcqrs-es
phatworx/devise_security_extension
May 2011 - Apr 2013
An enterprise security extension for devise, trying to meet industrial standard security demands for web applications.
Role in this project:Back-end Developer
Back-end DeveloperContributions:5 commits in 1 year 11 months
Contributions summary:Szymon primarily contributed to enhancing the `devise_security_extension` gem. Their work included adding fixes and new features, specifically related to password management and authentication hooks. They implemented changes impacting password expiration, archival, and validation rules, and integrated captcha functionality into authentication forms. Additionally, they modified the core files related to how devise functions.
web-applicationsmongoidsecuritydemandsindustrial
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