Daniel P. Clark

I am a relentless problem solver with a deep passion for crafting high-quality, maintainable, and performant software. My ability to break down complex ideas and communicate them effectively has been honed over years of experience, making me not just a developer but also a mentor and educator. I value clear communication, active listening, and thoughtful collaboration, ensuring that teams I work with thrive in both productivity and camaraderie.

I have a strong foundation in software architecture, prioritizing idiomatic code, best practices, and efficient design patterns. My expertise spans Ruby, Rust, and JavaScript, with a particular emphasis on Rails applications, systems programming, and API design. I am meticulous about writing and optimizing performant code, often using benchmarks, profiling, and testing (unit, integration, and property-based tests) to ensure reliability. My work in Dockerized environments, DevOps, and distributed systems has allowed me to design scalable, secure, and well-orchestrated infrastructures.

Background: My programming journey began as a child, inspired by my father, and later solidified as a passion-driven endeavor in 2001. By 2008, I was freelancing remotely, and in 2014, I transitioned into full-time software development, contributing to both Open Source and professional projects. I’ve worked extensively in high-scale environments, including my tenure at Pearson, where I played a key role in leading, architecting, and optimizing networked applications across Google Cloud, Kubernetes, and AWS.

Ideal Team Environment: I thrive in an environment that is collaborative, respectful, and driven by excellence. A team that values quality over speed, encourages mentorship, and embraces constructive peer review is where I perform best. I believe in graceful feedback, continuous improvement, and writing software that stands the test of time. Above all, I hold to the principle that people come before code, fostering a culture where individuals are valued, ideas are refined through discussion, and technical challenges are met with a spirit of shared problem-solving.

Designed, developed, and actively maintain Rutie, a library that enables seamless interoperability between Ruby and Rust, allowing developers to embed Ruby code in Rust applications or call Rust code from Ruby. Key contributions include:

• Performance & Safety: Leverages Rust’s memory safety while enabling Ruby extensions without needing C bindings.
• Ease of Use: Provides an idiomatic Rust API for Ruby integration, reducing boilerplate and complexity.

With the first release of this project, I improved my Rails site’s page load times by over 30%. Through careful performance analysis, I identified a key bottleneck in a critical Ruby method and rewrote it in Rust for significant speed gains. Over time, I expanded this optimization effort, rewriting 15 core methods in Rust, each contributing to faster execution and improved efficiency across the application. FasterPath continues to demonstrate the power of targeted performance optimizations by integrating Rust for computationally intensive operations within Ruby applications.

Experienced in writing clean, maintainable Ruby code with a strong focus on testing and best practices. Deep understanding of the language; and both RSpec and MiniTest, having used RSpec extensively for Rails applications and MiniTest for developing Ruby gems. Skilled in test-driven development (TDD) and behavior-driven development (BDD), with experience in mocking, stubbing, and integration testing using tools like VCR, WebMock, Capybara, and Selenium.

I’ve also gained much experience in implementing Rust code to interface directly with Ruby’s C API. I’ve worked with many APIs and designed abstraction layers, including API Gateway, Facade Pattern, and Adapter Pattern to simplify their use.

Experienced Ruby on Rails developer, specializing in building and optimizing scalable applications. Skilled in modern Rails features, front-end integration, and backend optimizations.

• Modern Rails Development: Turbo, AJAX, UJS, VueJS, ActionCable, WebSockets, RailsEngines
• Frontend & Asset Management: JavaScript, CSS, SASS, Tailwind, Bootstrap, Rails asset pipeline, build tools (Webpacker, Importmaps, Esbuild)
• Performance & Optimization: Arel, SQL query optimization, lazy loading views/queries, page load time reduction, data collection efficiency
• API Development: Full-stack development, RESTful APIs, JSON:API, background jobs (Sidekiq, DelayedJob, Resque, RabbitMQ)
• Infrastructure & DevOps: Docker multi-stage builds, application forking, security best practices (CSRF protection), Rails upgrades & maintenance

Experienced in writing performant, idiomatic Rust code with a focus on systems programming, concurrency, and foreign function interfaces (FFI).

• Rutie (Author & Maintainer): Designed and actively maintain Rutie, a library enabling seamless Ruby & Rust integration, allowing developers to embed Ruby in Rust and vice versa.
• Multi-Threading & Parallelism: Developed Abrute, a multi-threaded encryption brute-force testing tool leveraging all CPU cores and supporting distributed computing via JSON API aggregation.
• FFI & C Interoperability: Extensive experience in foreign function interfacing, from wrapping C libraries in Rust (FasterPath) to building Rutie for deep Ruby/Rust interoperability.
• Performance & Benchmarking: Strong background in optimizing Rust applications, including extensive benchmarking and low-level performance tracking.

Experienced in standalone microservice JavaScript applications running in Docker for both local and production environments. Skilled in integrating JavaScript seamlessly with Ruby on Rails applications, including advanced authentication flows.

• Authentication & OAuth Integration: Developed custom JavaScript interception hooks to integrate a third-party OAuth provider with Devise in a Rails backend.
• Frameworks & Libraries: Proficient in Vanilla JavaScript, VueJS, jQuery, UnderscoreJS, CoffeeScript, AJAX, Turbolinks, and Turbo.
• Testing & Automation: Experience with Jest and Mocha for unit and integration testing.
• Performance & Optimization: Optimized front-end interactions and asynchronous data loading for improved user experience.

Experience in designing and optimizing containerized environments for applications and microservices.

• Built optimized Docker containers tailored to various applications and microservices.
• Designed Docker network infrastructures with public and private networks.
• Implemented cross-application networking, integrating APIs, OAuth, OmniAuth, Redis, and RabbitMQ.
• Created local development environments that mirror multi-application production deployments.
• Developed test suites supporting both back-end and front-end browser testing.
• Set up Continuous Integration (CI) pipelines with Docker-based workflows.
• Engineered co-dependent and independent docker-compose environments, including multiple interconnected stacks.

I have grown up with Linux and worked extensively with it throughout my career.

• Professional Infrastructure Management: Managed Linux containers across Amazon AWS, Google Cloud, and Kubernetes, optimizing deployments and scaling applications.
• System Administration & Automation: Extensive experience in system builds, configurations, management, and backups, with strong proficiency in shell scripting for automation.
• Docker & Containerization: Deep expertise in Dockerfile configurations and container builds, refining deployment processes for optimized performance and security.
• Networking & Security: Advanced experience in remote access management, secure tunnels, firewall configurations, and networking.

Extensive experience building, integrating, and consuming APIs, including authentication and third-party service integrations.

• API Client Development: Authored Trav3, a Ruby API client library for Travis CI, enabling streamlined interaction with their API.
• Third-Party Integrations: Built applications integrating with Twilio, Evernote, Google Contacts, Travis CI, Microsoft, and various public and private APIs.
• Authentication & Security: Experienced with OAuth and OmniAuth, implementing secure authentication flows across multiple applications.

• Proficient in: Rust(Since Oct 2015), Ruby(Since early 2012), Ruby on Rails, Hutch, TDD, Capybara, Docker, REST, various APIs, Git, JavaScript, jQuery, CSS, Gem authoring, HTML5, JSON, Linux SysAdmin, Unix Shell Scripting, Computer Technician, VIM, AJAX
• Web automation with: Continuous Integration, Mechanize, Nokogiri, Selenium, and Watir
• Moderate experience in CoffeeScript, Crystal, Windows SysAdmin, ActionCable, Agile, Assembly, Bash, Batch, CGI, CMS, Django, Encryption, FFI, FishShell, Metaprogramming, OpenSSL, PostgreSQL, Python (Since 2001), RSS, SEO, SOLID, XML, Security Practices, VueJS, Ruby C API
• Studying: Algorithms, CoffeeScript, Rust, Design Patterns, Ruby C API, VueJS, Haskell, Functional Programming

At Pearson, I had the privilege of working with a small, highly skilled team as a Lead Web Developer, where I played a key role in system architecture, development, DevOps, and mentoring. Our work involved managing a complex ecosystem of interconnected applications, integrating third-party user management systems, and ensuring seamless interoperability across diverse platforms.

• Architecting Scalable Systems: Designed and developed networked applications running in Google Cloud (Kubernetes), later leading efforts to migrate the entire system to Amazon AWS, ensuring high availability and scalability.
• Leadership & Mentorship: Provided technical guidance and hands-on training, instilling best practices in code maintainability, security, and performance optimization. Led by example while fostering a collaborative, growth-focused environment.
• Software Development & Security: Built new Ruby-based microservices with minimalist dependencies to reduce security vulnerabilities and streamline maintenance. This addressed critical bottlenecks caused by frequent JavaScript ecosystem security updates, improving both release efficiency and long-term security.
• DevOps & Infrastructure Management: Took on primary DevOps responsibilities after our dedicated DevOps engineer left, managing containerized environments, automated deployments, and CI/CD pipelines.
• System Reliability & Maintainability: Applied deep language and application design expertise—particularly in Ruby—to ensure codebase longevity, maintainability, and alignment with best practices.

Throughout my time at Pearson, I remained committed to solving complex challenges with efficient, secure, and maintainable solutions, contributing to both technical excellence and team success.

I have been writing educational blogs for many years at 6ftdan.com, covering programming languages, software development, and personal growth. Additionally, I have freelanced as a technical writer for CloudBees/CodeShip, where I authored articles on various technologies, best practices, and software development methodologies. My writing focuses on delivering clear, insightful, and practical content to help developers enhance their skills and understanding.

Contributed to charity-driven Rails development projects, collaborating with teams to build mission-critical applications that support education, conservation, and community-driven initiatives.

• 2016 – Virginia Working Landscapes:
  Joined a team of developers to build a Rails-based cataloging system for documenting biodiversity. This platform helps researchers and conservationists track species populations and identify potential environmental risks, aiding efforts to protect endangered species.

• 2017 – Loudoun Codes:
  Participated in a team of about 10 developers to create a high school programming competition platform in Rails. The system:

  • Executes and evaluates student-submitted code across multiple programming languages. Automates grading, ranking, and penalty calculations with a live scoreboard system.
    
    
  • My primary contribution was implementing Docker-based language runners for Ruby, Python, C++, Rust, and Crystal, ensuring isolated and secure execution of competition code. This work was later refined and extended by Chris Hoffman.

Through Ruby for Good, I contributed technical expertise to meaningful projects, ensuring scalability, maintainability, and impact in education and environmental conservation.

Full stack Rails developer and CTO. Rails, Ruby, AJAX, JavaScript, jQuery, APIs, OAuth, OmniAuth, Devise, ActiveAdmin, Heroku, and much more.

Chris Kottom authored the book “The Minitest Cookbook” — with three weeks to go until it was due to be published I read through the book twice giving editing advice on each iteration. In 2017 I also gave a final proof read for Chris Kottom’s “Developing Rails API Applications” book.

Participated in Rails Rumble for three consecutive years, collaborating with teams of strangers (or working solo) to rapidly design, develop, and launch innovative web applications within 48 hours.

• 2014 – YouTube Scraper & Embedded Video System:

  Joined a team of three strangers from Twitter to develop a web app focused on scraping and embedding YouTube videos. Built the video scraping interface and helper methods for seamless embedded playback while also contributing as a core Rails developer.

• 2015 – TrenderCast (Podcast Subscription & Trends Platform):

  Formed a new team via Twitter and led the development of TrenderCast, a platform for tracking podcast trends and subscriptions. This project was my vision, and I served as the primary Rails developer, delivering a functional prototype within the 48-hour competition window.

• 2016 – Real-Time Poker Game Server (Solo Project):

  Competed solo, focusing on experimenting with new Rails technologies—specifically WebSockets and ActionCable. Designed and built a real-time poker game server, implementing:

  • Game tables, seat assignments, and card dealing
  • Live chat functionality for player interactions
  • Real-time updates using ActionCable

  Completed core game mechanics within the competition’s time constraints, gaining valuable experience in real-time Rails applications.

Designed full website automation for popular sites using Watir and Watir-webdriver in the Ruby language.

Designed a script to pay all site members who’ve authored content; all appropriate fees for student memberships and subscriptions, via the PayPal API using Python.

Designed a basketball tournament ranking application which ranked teams on many different criterea. Designed my own flat file database system to keep records in CSV format. This was used to rank a multi-day interstate basketball tournament.

• Ruby for Good: Contributed to charity Rails development projects for Virginia Working Landscapes (wildlife cataloging) and Loudoun Codes (high school coding competitions). Developed Docker-based language runners for multiple programming languages.
• Core & Ecosystem Contributions: Made direct contributions to major Open Source projects, including Ruby, Ruby on Rails, Crystal, RubyGems, Fish Shell, RVM, Bundler, and OmniContacts.
• Rutie (Ruby & Rust Integration): Maintains and expands Rutie, an abstraction layer for seamlessly integrating Ruby and Rust. Adopted and enhanced multiple projects into Rutie’s ecosystem.
• Authored Libraries:
  • PolyBelongsTo — Advanced ActiveRecord association library for polymorphic relationships in Rails.
  • DynaSpan — A Rails AJAX helper for dynamically modifying text content on web pages.
  • 80+ Open Source Libraries — Published and contributed to over 80 projects on GitHub, spanning Ruby, Rust, and JavaScript.
• Early Open Source Game Development: Released Py Connect Four (2002), a Python-based SDL game built with PyGame, offering a complete, installable, and functional game experience.

• Rails Frontend Testing with JavaScript Insights
• Refactoring for the Tell Don’t Ask Pattern
• VueJS Components with CoffeeScript for Rails
• VueJS as a Frontend for Rails
• Micro Backups of Your Git Dev Work
• Understanding Rust Loops
• ProxMox: A VM Server For Your Home
• Rust Design Considerations with Borrowing
• Mixing Ruby and Rust on Heroku
• Improving Ruby Performance with Rust
• Creating Configuration Objects in Ruby
• Understanding Lifetimes in Rust
• Let’s Talk About Shell Scripting
• Elixir Envy ▷ Ruby
• Advanced Enumeration with Ruby
• Graphing Benchmark Results in Ruby
• Refactoring and Design Patterns
• Crystal from a Rubyist’s Perspective
• ActionCable: The Missing Guide
• Creating Powerful Command Line Tools in Ruby
• Leveling up with Git
• Working with the Evernote API in Rails
• Creating Advanced ActiveRecord DB Queries with Arel
• Get Started Quickly with Docker and Sidekiq
• Building a Well-Polished Ruby Gem
• Re: What is the splat operator doing here?
• Getting Started with Minitest
• Managing Private Dependencies with Bundler
• The Pros and Cons of Ruby Refinements
• How to Inspire Community in Programming
• Visualizing Algorithms Before Implementation
• Coming to Rust from Ruby
• Unobtrusive JavaScript via AJAX in Rails
• A Deep Dive into Ruby Scopes
• How to Build the Ultimate Remote Pair Programming Environment
• Encrypted Linux Backup with Google Drive and Duplicity
• Use Ruby’s Refinements Anywhere With An Anonymous Class
• Rails: Has One Through Polymorphic Relation
• Ruby: Bindings Across Inheritance
• 101 Ruby Code Factoids
• Ruby: Arrays by Example
• Iterative Evaluation
• Implement a Lazy Hash in Ruby
• Rails Rumble — the Experience
• Introspection by Design in Ruby
• Install Ubuntu 15 Over the Network PXE/BootP/TFTP NetBoot
• Ruby Refinements — Not quite ready for production
• Rails’ HashWithIndifferentAccess
• Switching From Unicorn to Puma on Heroku is Easy!
• Speed Up Your Rails Views By Deferring Changes
• Rails: Don’t “pluck” Unnecessarily
• Fake a SMTP Server with Python for Rails Testing
• HABTM: You Don’t Need It
• Chaining an Array into Arel ors
• Private Module Methods in Ruby
• Have problems testing methods that query ActiveRecord?
• Documenting Your Code
• ActiveRecord vs Me… Round 1 — FIGHT!
• Rails 4’s Aweseom enums
• Different Collection Types in Ruby
• Hooks
• More UJS fun with Accordion Content
• Substitution with Regex Groupings
• Ruby: Actionable Meta
• Configuration With a Singleton Instance
• Numeric Bases and Defining Your Own
• Ruby: The Case for Case
• Version Both Your Github Repo and Gem
• Value Assignment and Deferment with Lambdas/Procs
• Writing methods for both class and instance levels
• Minitest with Watir-webdriver
• Some Basic Ruby Tools for Sniffing out Errors
• A Glimpse at Tail Call Recursion
• Use the given project generators
• Setting up Remote SSH Access to your Ubuntu Box
• Rails Polymorphic Associations
• Do It All With Ruby
• Getting Into Rails Model Queries
• Using Ruby Object Type Classes to Safely Build Data
• Discovering UJS with AJAX
• Rails Helper Methods
• or
• Learning Your First Programming Language
• Refinements over Monkey-patching
• The 500 Millisecond Rails Partial
• Email Composer/Editor Template for WebDevs
• Vanilla JavaScript — Stepping into the language
• Encryption in Ruby on Rails
• JavaScript is easy with jQuery
• Dealing with Rails 4 forms and params
• When to use Ampersand and/or Colon with Proc, Map, and Inject
• “Assume Everything Will Break” Development
• Free Travis CI for your Open Source project
• Ruby & Ruby on Rails Methods for Discovery Part 1
• Create a Game Instance in Rails
• Manual Polymorphic Creation in Rails

• US English (Native)
• Spanish (studying)
• Japanese (studying)

Graduate High School: Clark Christian High School 2003