Greg Navis, Developer in Szczecin, Poland
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Greg Navis

Verified Expert  in Engineering

Software Developer

Location
Szczecin, Poland
Toptal 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.

Back-endWeb DevelopmentAPI DesignCode ReviewFull-stackGitTest-driven Development (TDD)AutomationRuby on Rails (RoR)RubyPythonContinuous DeploymentHerokuFront-endWeb Scraping

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, Python...

Experience

Ruby on Rails (RoR) - 9 yearsPython - 9 yearsTechnical Leadership - 8 yearsProduct Design - 7 yearsPostgreSQL - 7 yearsReact - 6 yearsTypeScript - 3 yearsElixir - 2 years

Availability

Part-time

Preferred Environment

Git, Browsers, Terminal, Linux, Visual Studio Code (VS Code), MacOS

The most amazing...

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

Work Experience

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, Git, Python, Continuous Deployment, JavaScript, Leadership, Software Architecture, Python 3, Flask

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, Git, Continuous Deployment, JavaScript, Leadership, Software Architecture

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), Git, Continuous Deployment, JavaScript, Leadership

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), Git, Software Architecture

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), Git, Continuous Deployment, Fintech

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, Git, Continuous Deployment, Leadership, Software Architecture

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), Git, Continuous Deployment, Leadership, Fintech, Software Architecture

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), Jenkins, Ansible, 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, Git

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: Git, Tornado, Flask, 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, Leadership, Software Architecture

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, Git, Software Architecture

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, Python, C++, HTML, Startups, APIs, Databases, Object-oriented Programming (OOP), Back-end, Web Development, Testing, Automation, Object-relational Mapping (ORM), Git

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)

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.

Languages

HTML, JavaScript, Ruby, Python, SQL, 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, Babel, Webpack, GitHub, Ansible, GIS, Jenkins, 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, APIs, Code Review, Team Mentoring, Full-stack, Back-end, Architecture, Web Development, Software Architecture, MVP Design, Mathematics, Product Design, Team Leadership, Technical Leadership, Startups, Consulting, Web Scraping, Front-end, Payment APIs, CI/CD Pipelines, 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

2006 - 2011

Master's Degree in Mathematics

University of Szczecin - Szczecin, Poland