toptal.com
Contact us: +1.888.867.7001
Greg Navis, Software Developer in Szczecin, Poland
Greg Navis

Software Developer in Szczecin, Poland

Member since October 24, 2016
Greg started programming at the age of 7 and still loves it at 34. He's worked in verticals like finance, banking, aerospace, healthcare, HR, retail, media and entertainment on web, mobile, desktop, and server products. His experience covers a spectrum of responsibilities—back end, front end, leadership, project management, product design, quality assurance, and developer coaching.
Greg is now available for hire
Hire Greg

Portfolio

  • Self-employed
    Heroku, PostgreSQL, Ruby on Rails (RoR), Ruby, APIs, API Design, Twilio, SQL...
  • Everest Health
    React, TypeScript, Ruby, Ruby on Rails (RoR), PostgreSQL, API Design, Heroku...
  • Rotabull
    Elixir, Phoenix, Heroku, PostgreSQL, TypeScript, C#, Stripe, API Design...

Experience

Location

Szczecin, Poland

Availability

Part-time

Preferred Environment

Git, Browsers, Terminal, Linux, Visual Studio Code, MacOS

The most amazing...

...product I've led development for is a payments platform that's processing over 80 million euros a year.

Employment

  • Principal

    2015 - PRESENT
    Self-employed
    • Contributed to several product development projects for various clients; my roles encompassed the back end, front end, full-stack development, product design, software architecture consulting, and technical mentorship.
    • Handled full-stack product development of a job board for a client.
    • Created product designs for a client's appointment scheduler.
    • Worked on product development of a personal finance social network for a client.
    • Integrated Google's Cloud Talent Solution for a client's project.
    • Migrated a continuous integration workflow from Kubernetes to Heroku, Semaphore, GitHub, and Jira; also built a custom integration to automate review app provisioning and automated localization updates from non-technical team members.
    Technologies: Heroku, PostgreSQL, Ruby on Rails (RoR), Ruby, APIs, API Design, Twilio, SQL, Startups, DevOps, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Architecture, Babel, Webpack, Apache Kafka, Web Development, Testing, CI/CD Pipelines, Automation, GitHub, Object-relational Mapping (ORM), MVP Design

  • Product Designer and Developer

    2021 - 2021
    Everest Health
    • Developed and designed end-to-end products, including requirements, product design, prototyping, and development.
    • Designed, prototyped, and developed drug spend optimization features. Major features included advanced SQL reporting queries, drug spending heat map, savings initiative projections, and executive reports.
    • Implemented and designed collaboration features—sharing and permissions.
    Technologies: React, TypeScript, Ruby, Ruby on Rails (RoR), PostgreSQL, API Design, Heroku, HTML, CSS, SQL, Product Design, Node.js, REST APIs, Startups, HTML5, REST, APIs, DevOps, Figma, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Babel, Webpack, Web Development, Testing, CI/CD Pipelines, Automation, Object-relational Mapping (ORM), MVP Design

  • Lead/Senior Developer

    2019 - 2021
    Rotabull
    • Led a team of 4-5 engineers that delivered new features. Major accomplishments are advanced quoting, invoicing and payment flows, and Stripe-Connect-based payments.
    • Collaborated with product management and design to ensure requirements were realistic, well-defined, and cost-effective.
    • Maintained complex integrations with Stripe Billing, Stripe Connect, SendGrid (inbound and outbound), QuickBooks, custom on-site ERP bridges.
    • Mentored developers through pair programming, code reviews, and one-on-ones.
    • Streamlined development processes—improved standup format and project management tooling, automated review app provisioning for acceptance testing, and reduced test suite flakiness.
    • Modernized the front end by migrating from Brunch and JavaScript to WebPack and TypeScript.
    • Enhanced a data entry flow used by contractors that increased their reliability.
    Technologies: Elixir, Phoenix, Heroku, PostgreSQL, TypeScript, C#, Stripe, API Design, Python, Test-driven Development (TDD), React, HTML, SCSS, CSS, SQL, Team Leadership, Technical Leadership, Node.js, REST APIs, Startups, HTML5, REST, XML/XSLT, APIs, DevOps, Web Scraping, Figma, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Amazon Web Services (AWS), Architecture, Babel, Webpack, Python 3, Web Development, Testing, CI/CD Pipelines, Automation, GitHub, Object-relational Mapping (ORM)

  • Back-end Engineer

    2019 - 2019
    UpLift, Inc.
    • Reviewed and improved product designs by simplifying critical user flow and ensuring the product vision was technically feasible.
    • Designed and implemented SFTP to Amazon S3 synchronization and media asset discovery.
    • Implemented and designed an FFmpeg-based video processing back end.
    • Applied a GraphQL with Node.js, involving a complex SQL query, to back new reporting features.
    • Diagnosed and resolved PostgreSQL performance issues affecting key product features.
    • Introduced end-to-end testing based on browser-generated HAR files.
    Technologies: Python, PostgreSQL, GraphQL, Django, API Design, CSS, SQL, REST APIs, REST, APIs, Databases, Object-oriented Programming (OOP), Back-end, Amazon Web Services (AWS), Babel, Webpack, Python 3, Web Development, FFmpeg, Testing, CI/CD Pipelines, Automation, GitHub, Object-relational Mapping (ORM)

  • Software Developer

    2018 - 2018
    LucaLabs
    • Designed and implemented a framework for generic financial statements, including balance sheet, profit, and loss, which reduced implementation effort and increased reliability.
    • Introduced operation classes and form objects to increase implementation consistency and reliability.
    • Built custom linter rules for enforcing project-specific requirements, which streamlined development and increased reliability.
    • Implemented supplier and customer invoicing workflows like uploading, previewing, editing, and booking, including a web-based invoice editor.
    • Implemented features like AWS SES-base inbox, permission-based authorization scheme, and CSV/XLSX importers.
    Technologies: Stimulus, GitLab, Heroku, Ruby on Rails (RoR), Ruby, MySQL, Test-driven Development (TDD), HTML, SCSS, jQuery, CSS, SQL, Node.js, REST APIs, Startups, HTML5, REST, APIs, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Amazon Web Services (AWS), Web Development, Testing, CI/CD Pipelines, Automation, Object-relational Mapping (ORM)

  • Back-end Developer

    2017 - 2018
    ONN
    • Designed and implemented an API, including development docs consumed by an iOS app.
    • Implemented and designed a support panel, including real-time chat and voice calls across the web and iOS.
    • Designed and implemented custom subscription logic.
    • Integrated with Twilio (messaging and voice calls) and Braintree (payment processing).
    • Set up Heroku-based infrastructure and continuous delivery (CD).
    Technologies: Ruby, Ruby on Rails (RoR), APIs, Heroku, PostgreSQL, Twilio, Braintree API, API Design, Test-driven Development (TDD), React, HTML, Twilio API, CSS, SQL, Product Design, Node.js, REST APIs, Startups, HTML5, REST, DevOps, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Amazon Web Services (AWS), Architecture, Webpack, Web Development, Testing, CI/CD Pipelines, Automation, GitHub, Object-relational Mapping (ORM), MVP Design

  • Lead Software Developer

    2014 - 2016
    ClubCollect
    • Enhanced and maintained a billing system processing millions of euros a year.
    • Designed and implemented a single-entry accounting system for managing automatic payment and payout processing, making them auditable and reducing the risk of incorrect payouts.
    • Refactored and enhanced the payment flow logic to accommodate features requested by customers in a new market.
    • Implemented a financial reporting dashboard for use by the company management.
    • Helped to hire and onboard a team of three engineers and lead them afterward.
    • Optimized development processes by integrating GitHub, Slack, and Semaphore. Introduced a company-wide coding style automatically enforced during continuous integration.
    Technologies: Mailgun, PostgreSQL, Heroku, Bootstrap, JavaScript, CSS, HTML, Ruby on Rails (RoR), Ruby, API Design, Test-driven Development (TDD), jQuery, SQL, Product Design, Team Leadership, Technical Leadership, Node.js, REST APIs, Startups, REST, XML/XSLT, APIs, DevOps, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Amazon Web Services (AWS), Architecture, Web Development, Testing, CI/CD Pipelines, Automation, GitHub, Object-relational Mapping (ORM)

  • Software Developer

    2013 - 2014
    Adbeat
    • Implemented a system for identifying the most significant websites in the US display advertising space.
    • Wrote a custom test suite for ad identification code.
    • Implemented an admin panel providing some information about the internal operations of the scraper.
    • Automated scraping proxy set up with Ansible ensuring proxy are functionally equivalent.
    • Introduced Vagrant for local development to reduce development and production discrepancies.
    • Automated build to a great extent with Jenkins CI.
    Technologies: Amazon Web Services (AWS), Vagrant, Jenkins, Ansible, PyQt, Python, Amazon EC2 API, HTML, SQL, REST APIs, Startups, XML/XSLT, APIs, DevOps, Web Scraping, Databases, Object-oriented Programming (OOP), Back-end, Web Development, Testing, CI/CD Pipelines, Automation, Scraping, Web Crawlers, HTML Parsing, XML Parsing

  • Lead Software Developer

    2012 - 2013
    Red Sky
    • Led a team of two developers working on networking services consumed by other teams.
    • Oversaw the development of a scraping proxy server that centralized scraping-related know-how.
    • Led and designed the development of an auto-completion aggregation service—exposing multiple third-party auto-completers via a standardized API.
    • Designed and led the development of a white-hat botnet used to distribute scraping workloads across multiple customer nodes.
    Technologies: dpkg, Git, Tornado, Flask, Twisted, Redis, MySQL, Python, API Design, Test-driven Development (TDD), SQL, Product Design, Team Leadership, Technical Leadership, REST APIs, Startups, REST, APIs, Web Scraping, Databases, Object-oriented Programming (OOP), Back-end, Architecture, Web Development, Testing, CI/CD Pipelines, Automation, Scraping, Web Crawlers, HTML Parsing, XML Parsing

  • Software Developer

    2011 - 2012
    Red Sky
    • Overhauled fraud detection code while reducing code mass ten times, increasing reliability and lead time.
    • Designed and implemented UI-driven test automation tool. Reduced testing feedback from weeks to minutes, identified and resolved numerous concurrency-related issues.
    • Implemented, designed, and maintained a game developer portal offering self-serve debugging tools. Reduced technical support overhead and increased game quality.
    • Created and specced a validation API that allowed to onboard a third-party contractor quickly.
    Technologies: MongoDB, Flash ActionScript, JavaScript, CSS, HTML, PHP, API Design, Test-driven Development (TDD), SQL, REST APIs, Startups, APIs, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Web Development, Testing, Automation

  • Software Developer

    2010 - 2011
    Red Sky
    • Enhanced and maintained an HTTP server used for file content delivery.
    • Implemented server monitoring and load balancing to optimize infrastructure use.
    • Implemented virtual file system (VFS) operations like open, close, read, write, and others for system-wide interoperability.
    • Designed and implemented a scriptable file system stress testing tool. Identified and resolved numerous concurrency-related defects before they affected production.
    Technologies: Linux, Fuse, Python, Boost, C++, HTML, Startups, APIs, Databases, Object-oriented Programming (OOP), Back-end, Web Development, Testing, Automation, Object-relational Mapping (ORM)

  • Software Engineer

    2007 - 2009
    Coriolis PRO
    • Designed and developed software for keeping track of signs placed along waterways.
    • Enhanced Autodesk MapGuide's web interfaces to support custom coordinate systems.
    • Prepared maps for rendering in various tools. Tested that data rendered correctly.
    Technologies: GIS, MySQL, JavaScript, PHP, XML/XSLT, APIs, Databases, Object-oriented Programming (OOP), Full-stack, Back-end, Front-end, Web Development, Testing, Object-relational Mapping (ORM)

Experience

  • ClubCollect
    https://www.clubcollect.com/en/

    A platform for collecting membership fees from sports clubs' members. I helped the CTO enhance, maintain, and troubleshoot a billing engine processing millions of euros a year. I also helped to hire and lead a team of three engineers.

    My biggest accomplishment was implementing a single entry accounting system that managed automatic and semi-automatic payouts of millions of euros a year.

  • LucaLabs
    https://www.lucaregnskap.no/

    Online bookkeeping and accounting platform for SMBs. I implemented core accounting features such as a framework for financial reporting like creating a balance sheet or an income statement and advanced supplier and client invoicing workflows, including interactive web-based invoice editors.

  • Active Record Doctor
    https://github.com/gregnavis/active_record_doctor

    Active Record Doctor helps you identify database issues before they hit production. I built the tool based on my consulting experiences assisting companies in optimizing their PostgreSQL databases. The tool was downloaded over 700,000 times (as of Nov 2021) and gathered a community of users and contributors.

  • Rotabull
    http://www.rotabull.com

    A platform for aircraft parts sales teams. I was a lead developer on a team of 4-5 other developers. Our biggest accomplishment was delivering complex quoting, invoicing, and payment workflows and maintaining integrations with Stripe Billing, Stripe Connect, and QuickBooks.

  • Everest Health

    A web app for hospital systems to help them optimize their drug spending. I designed and implemented new product features centered around discovering spending pockets, simulating cost-savings initiatives, and creating executive reports to help pharmacy teams pitch new initiatives to the management team.

Skills

  • Languages

    Ruby, Python, HTML, SQL, JavaScript, SCSS, C, CSS, Elixir, TypeScript, HTML5, Python 3, Flash ActionScript, PHP, C++, C#, GraphQL, XML/XSLT

  • Frameworks

    Ruby on Rails (RoR), Phoenix, Bootstrap, Knockout (Knockout.js), Redux, Django, Flask, Stimulus, Django REST Framework

  • Tools

    Git, Jenkins, Babel, Webpack, GitHub, Ansible, GIS, GitLab, Web GIS, Figma, Adyen Payments

  • Paradigms

    Continuous Deployment, Test-driven Development (TDD), Object-oriented Programming (OOP), Automation, Testing, Object-relational Mapping (ORM), REST, DevOps

  • Platforms

    Heroku, Linux, Twilio, Mailgun, Amazon Web Services (AWS), Apache Kafka

  • Other

    API Design, Mathematics, APIs, Code Review, Team Mentoring, Full-stack, Back-end, Architecture, Web Development, MVP Design, Product Design, Team Leadership, Technical Leadership, Startups, Consulting, Web Scraping, Front-end, Payment APIs, CI/CD Pipelines, Software Architecture, Leadership, Scraping, Web Crawlers, HTML Parsing, Tornado, Reverse Engineering, Keen.io, Open Source, Fintech

  • Libraries/APIs

    React, Stripe, REST APIs, Amazon EC2 API, Twilio API, Braintree API, jQuery, Node.js, Ruby ERB, Nexmo, NumPy, SymPy, FFmpeg

  • Storage

    PostgreSQL, Databases, XML Parsing, MongoDB, MySQL, Redis

Education

  • Master's Degree in Mathematics
    2006 - 2011
    University of Szczecin - Szczecin, Poland

To view more profiles

Join Toptal
Share it with others
Hire the top 3% of freelance developers TM