Publication
Learning Swift Programming: Is it Ready for Prime Time?
https://www.toptal.com/developers/swift/swift-is-it-ready-for-prime-time
Joshua is available for hire
Hire JoshuaJoshua Ballanco
Verified Expert in Engineering
Ruby on Rails Developer
Miami, FL, United States
Toptal member since January 14, 2014
Bio
Joshua is an architect, engineer, and scientist with experience building large-scale systems dealing with everything from massive amounts of video data to heavy web traffic. Joshua also has experience breaking monoliths into scalable microservice architectures and going the other way 'round. He's worked for Apple and AOL and has also led a group of 50+ consultants as their chief scientist.
Portfolio
Craft
Large Language Models (LLMs), Open-source LLMs, React Native, React, Mobile...
Piñata
Snowflake, Python, SOAP, Apache Airflow, Django, Automated Testing, Pinecone...
Deloitte
Clojure, ClojureScript, Automation, AWS Lambda, Automated Testing, SDKs...
Experience
- C - 16 years
- Ruby on Rails (RoR) - 14 years
- Ruby - 14 years
- Java - 14 years
- API Design - 10 years
- JavaScript - 10 years
- Python - 9 years
- Architecture - 8 years
Preferred Environment
Amazon Web Services (AWS), Docker, Heroku, Visual Studio Code (VS Code), Git, Emacs, Vim Text Editor, Linux, OS X, Tailwind CSS, Model Context Protocol (MCP), Agentic AI
The most amazing...
...bug I've fixed required taking a system that couldn't even handle two machines and scaling it to over twenty in less than four weeks before shipping a new OS.
Work Experience
Full-stack Tech Lead
2023 - 2024
Craft
- Developed an initial product concept into a functional, working proof of concept (PoC).
- Deployed custom fine-tuned large language models (LLMs) and integrated with a mobile application.
- Handled on-device and service-based speech-to-text and TTS interfaces for a mobile device.
- Implemented a custom admin interface for prompt evaluation and iteration.
- Minimized UI latency to improve user experience with the voice assistant.
Technologies: Large Language Models (LLMs), Open-source LLMs, React Native, React, Mobile, Voice, Speech-to-Text (STT), Text-to-Speech (TTS), Anthropic, Claude, ChatGPT, Terraform, GraphQL, CI/CD Pipelines, Containerization, Continuous Delivery (CD), Infrastructure as Code (IaC), Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, Fractional CTO, Notion, AI Voice Agents, Conversational AI, Natural Language Processing (NLP), VoiceBot, Data Modeling, Database Structure, Generative Artificial Intelligence (GenAI), SaaS
Senior Software Engineer
2023 - 2023
Piñata
- Developed a data import workflow to ingest disparate data from internal and external systems to facilitate work by the data analysis team.
- Implemented a custom adapter to facilitate data exchange between a modern Django app and a legacy 3rd-party SOAP service.
- Set up, configured, and educated team on the use of Apache Airstream to manage and run recurring data transformation and import tasks.
Technologies: Snowflake, Python, SOAP, Apache Airflow, Django, Automated Testing, Pinecone, SDKs, Poetry, Cloud Firestore, HTML5, XML, Docker, FastAPI, OAuth, Open Source, Tailwind CSS, PostgreSQL, Single-page Applications (SPAs), Communication, Expo, Mobile, Figma, OpenAI, Vercel, Flask, NestJS, GitHub, Web Scraping, Data Scraping, NoSQL, Python 3, Single Sign-on (SSO), API Testing, Amazon S3 (AWS S3), Web Applications, Cloud Storage, Inventory Management, POS, Auth0, Application Performance Monitoring, JSON, Material UI, Swagger, Jest, Software Development Lifecycle (SDLC), Software Design, Integration, Cloud Infrastructure, BigQuery, Google BigQuery, Amazon Aurora, Automation, Anthropic, Claude, GraphQL, CI/CD Pipelines, Containerization, Continuous Delivery (CD), Distributed Systems, Infrastructure as Code (IaC), Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, Notion, RESTFul APIs, Data Modeling, Database Structure, SaaS, Scalable Architecture
Tech Lead
2018 - 2022
Deloitte
- Developed a system for the automation of property tax assessments and government-issued communications.
- Implemented a custom file-upload mechanism that satisfied legal archival requirements.
- Wrote a custom OData client interface using NTLMv2 authentication to fetch and post data to various 3rd-party systems.
- Collaborated with cross-functional architecture and business analyst teams to scope and prioritize work on new features.
- Supported operations on issues discovered during production deployments.
Technologies: Clojure, ClojureScript, Automation, AWS Lambda, Automated Testing, SDKs, General Data Protection Regulation (GDPR), HTML5, Docker, AWS Elastic Beanstalk, Authentication, NPM, WebSockets, Open Source, SAML, Tailwind CSS, PostgreSQL, Single-page Applications (SPAs), Leadership, Communication, Backbone.js, GitHub, Web Scraping, Data Scraping, NoSQL, Amazon S3 (AWS S3), Cloud Architecture, Web Applications, Cloud Storage, JSON, Swagger, Software Development Lifecycle (SDLC), Software Design, Integration, Cloud Infrastructure, Amazon Aurora, Large Language Models (LLMs), Terraform, CI/CD Pipelines, Continuous Delivery (CD), Distributed Systems, Infrastructure as Code (IaC), Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, Natural Language Processing (NLP), RESTFul APIs, Data Modeling, Database Structure, Scalable Architecture
Expert Full-stack Developer
2020 - 2021
CoreValue Holdings, LLC
- Updated a legacy application from Rails 3.0 to Rails 6.0.
- Refactored survey and data input system to facilitate further customization and other new feature development.
- Expanded the core product to serve new industries and an expanded customer base.
Technologies: Ruby, JavaScript, Ruby on Rails (RoR), PostgreSQL, CoffeeScript, Angular, Heroku, Accounting Software, jQuery, Stimulus, CTO, Team Leadership, Code Review, Back-end, Full-stack, Vanilla JS, Full-stack Development, Software Architecture, Technical Leadership, Recommendation Systems, Artificial Intelligence (AI), Machine Learning, React Native, Performance, Sidekiq, Amazon RDS, AWS Lambda, Serverless, Amazon DynamoDB, Amazon CloudWatch, Amazon Cognito, Prompt Engineering, Generative Pre-trained Transformers (GPT), CSS, HTML, TypeScript, Front-end, Content Delivery Networks (CDN), Stripe, REST APIs, Test-driven Development (TDD), Slack API, Automated Testing, HTML5, Docker, NPM, WebSockets, Open Source, Single-page Applications (SPAs), Data Visualization, NestJS, GitHub, Supabase, Single Sign-on (SSO), PDF, API Testing, Amazon S3 (AWS S3), Cloud Architecture, Web Applications, Cloud Storage, Inventory, Application Performance Monitoring, SVG, JSON, Software Development Lifecycle (SDLC), Software Design, Integration, Cloud Infrastructure, BigQuery, Google BigQuery, Amazon Aurora, CI/CD Pipelines, Continuous Delivery (CD), Infrastructure as Code (IaC), Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, Fractional CTO, RESTFul APIs, Data Modeling, Database Structure, SaaS, Scalable Architecture
Full-stack and Back-end Developer
2020 - 2021
Digital Swiss Gold (USA) LLC
- Enhanced a mobile app prototype in preparation for a wide-scale production launch.
- Refactored an order-processing back-end to enable distributed deployment.
- Implemented various analytics tracking capabilities to monitor customer engagement.
Technologies: Java, SQL, API Hooking, React, API Integration, A/B Testing, Accounting Software, Team Leadership, Startups, Code Review, Back-end, Full-stack, Full-stack Development, APIs, Software Architecture, Third-party APIs, Mobile UX, Apollo, Amazon EKS, MongoDB Atlas, AWS Lambda, Serverless, CSS, HTML, TypeScript, Content Delivery Networks (CDN), iOS, Android, Mobile Development, Firebase, Google Cloud Platform (GCP), Stripe, REST APIs, API Gateways, Next.js, Test-driven Development (TDD), Slack API, Electron, Desktop App Development, SDKs, Cloud Firestore, HTML5, Authentication, NPM, OAuth, Open Source, PostgreSQL, Single-page Applications (SPAs), Figma, Azure, Backbone.js, GitHub, Web Scraping, NoSQL, C#.NET, Python 3, Amazon S3 (AWS S3), Cloud Architecture, Web Applications, Cloud Storage, Swift, SwiftUI, TestFlight, Auth0, Application Performance Monitoring, JSON, Material UI, Jest, Software Development Lifecycle (SDLC), Mobile App Development, Software Design, Cloud Infrastructure, CI/CD Pipelines, Continuous Delivery (CD), Distributed Systems, Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, Fractional CTO, RESTFul APIs, Database Structure, SaaS, Scalable Architecture
Native MacOS Developer
2019 - 2020
Coscreen, Inc.
- Improved on a mechanism to transmit screen contents between clients, doubling frame rate as a result.
- Eliminated launch bugs and isolated potential races to improve successful connections by 20%.
- Added native extensions to an Electron application to enable shared control of a client machine.
Technologies: Objective-C, MacOS, C, Software Development Lifecycle (SDLC), Mobile App Development, Software Design, CI/CD Pipelines, Continuous Delivery (CD), Observability Tools, Scalable Architecture
Senior Software Developer
2013 - 2019
Glencoe Software
- Supported the migration of a Spring/Hibernate system from PostgreSQL to Oracle.
- Designed and implemented a distributed messaging system to connect various components in a data collection pipeline.
- Created JNI-based bindings for a JPEG XR decoder written in C.
- Wrote a library to coordinate the submission of jobs to an HPC grid facility from a Python/Django web app.
- Implemented a custom Window's URL handler to enable launching local applications against data on a central server from within a browser window.
Technologies: Django, Python, Hibernate, Spring, Java, Code Review, Back-end, Full-stack Development, APIs, Software Architecture, Third-party APIs, Artificial Intelligence (AI), Machine Learning, Amazon EKS, C#, .NET, AWS Lambda, Serverless, CSS, HTML, Content Delivery Networks (CDN), Test-driven Development (TDD), Twilio API, Arduino, SDKs, General Data Protection Regulation (GDPR), HIPAA Compliance, HTML5, XML, FastAPI, Healthcare, AWS Elastic Beanstalk, NPM, OAuth, WebSockets, Open Source, SAML, Sinatra, PostgreSQL, Flask, GitHub, C, NoSQL, Python 3, Amazon S3 (AWS S3), Web Applications, Cloud Storage, SVG, Animation, JSON, Swagger, Software Development Lifecycle (SDLC), Software Design, Integration, Cloud Infrastructure, Amazon Aurora, Containerization, Continuous Delivery (CD), Distributed Systems, Monitoring, Observability Tools, Operational Excellence, REST, System Architecture, RESTFul APIs, Scalable Architecture
Senior Architect
2017 - 2018
Simple Global, Inc.
- Led company-wide planning for a transition from a single monolith to microservice-based architecture.
- Guided decision making around the selection of technology stack, deployment infrastructure, and the continuous delivery pipeline.
- Designed and implemented OpenAPI specification, driven API documentation, and automated testing.
- Assisted with metrics collection and ETL workflow for accounting data.
Technologies: DevOps, Code Architecture, API Architecture, API Design, Spring, Java, Node.js, Express.js, Architecture, CTO, Team Leadership, Startups, Code Review, Full-stack Development, Software Architecture, Technical Leadership, Amazon RDS, MongoDB Atlas, CSS, HTML, Content Delivery Networks (CDN), Google Cloud Platform (GCP), Microservices, REST APIs, API Gateways, Twilio API, SDKs, General Data Protection Regulation (GDPR), HTML5, Authentication, NPM, OAuth, Open Source, Leadership, Shopify API, GitHub, NoSQL, C#.NET, Amazon S3 (AWS S3), Cloud Architecture, Web Applications, Cloud Storage, Inventory, Inventory Management, Auth0, Application Performance Monitoring, JSON, Swagger, Software Design, Cloud Infrastructure, Containerization, Continuous Delivery (CD), Distributed Systems, Observability Tools, Operational Excellence, REST, System Architecture, RESTFul APIs, Scalable Architecture
Senior Software Engineer
2014 - 2018
Hendrick Automotive
- Designed and deployed AWS CodeDeploy/CF-based architecture for deploying internal back-office apps.
- Developed APIs to support business analytics.
- Migrated an existing code base from Datomic to PostgreSQL.
- Developed a Clojure-based web application to manage employee performance and goal setting.
- Developed middleware services to connect an array of third-party back-office systems.
Technologies: Amazon Web Services (AWS), React, Ruby on Rails (RoR), Datomic, Clojure, CTO, Team Leadership, Code Review, Back-end, Full-stack Development, APIs, Software Architecture, Third-party APIs, Recommendation Systems, Scalability, Amazon RDS, C#, .NET, CSS, HTML, Front-end, Video Streaming, Microservices, REST APIs, Test-driven Development (TDD), Twilio API, Electron, Automated Testing, SDKs, HTML5, XML, AWS Elastic Beanstalk, Authentication, NPM, OAuth, Open Source, SAML, Sinatra, Single-page Applications (SPAs), Communication, Data Visualization, Azure, Backbone.js, GitHub, NoSQL, Amazon S3 (AWS S3), Web Applications, Cloud Storage, Auth0, Application Performance Monitoring, JSON, Swagger, Mobile App Development, Software Design, Integration, Cloud Infrastructure, Amazon Aurora, Continuous Delivery (CD), Operational Excellence, REST, System Architecture, RESTFul APIs, Scalable Architecture
Software Engineer — RoR
2014 - 2014
Centzy
- Extended a CMS-like system to host FAQ content.
- Updated HTML and CSS for various static pages.
- Implemented a dynamically resizing button menu.
- Updated responsive design elements for mobile browsers.
- Fixed a variety of minor bugs in a legacy Rails codebase.
Technologies: Clojure, CSS, JavaScript, Ruby on Rails (RoR), Product Management, Startups, Code Review, Full-stack, HTML, Front-end, Test-driven Development (TDD), NPM, Open Source, Single-page Applications (SPAs), Shopify API, GitHub, Web Applications, SVG, Software Design, Operational Excellence, Scalable Architecture
Chief Scientist
2011 - 2013
Burnside Digital
- Developed client infrastructures using various components of Amazon Web Services.
- Worked with teams at RedHat to build solutions on the JVM and JBoss platforms.
- Developed components of an SOA infrastructure that supports a variety of client projects, including the CityEats platform we developed for Scripps Network Interactive.
- Presented technical solutions at software conferences around the world.
- Helped introduce and develop new technologies with our team of 20+ software engineers.
Technologies: Chef, Java, Clojure, Objective-C, JavaScript, Ruby on Rails (RoR), Agile, CTO, Team Leadership, Code Review, Full-stack Development, Technical Leadership, Scalability, CSS, HTML, Video Streaming, Content Delivery Networks (CDN), Mobile Development, REST APIs, Test-driven Development (TDD), Desktop App Development, Automated Testing, SDKs, Open Source, SAML, Leadership, GitHub, C, NoSQL, Web Applications, Cloud Storage, Application Performance Monitoring, JSON, Swagger, Software Design, Integration, Cloud Infrastructure, Amazon Aurora, REST, System Architecture, Scalable Architecture
Support Engineer
2011 - 2011
Exceptional
- Fixed bugs reported on the main Exceptional.io app.
- Responded to support requests from Exceptional customers.
- Developed integration between Exceptional and Pivotal Tracker.
- Monitored servers for service interruptions and helped to diagnose, troubleshoot, and fix emerging issues.
- Assisted with transitioning the technology stack to new owners.
Technologies: Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Redis, Memcached, JavaScript, Ruby on Rails (RoR), Startups, Code Review, Back-end, Full-stack, Vanilla JS, Full-stack Development, Mobile UX, CSS, HTML, Front-end, Test-driven Development (TDD), Automated Testing, Open Source, Sinatra, Backbone.js, GitHub, Web Applications, Software Design, REST, Scalable Architecture
Back-end Software Engineer
2010 - 2011
AOL
- Migrated the primary CMS application from Ruby Enterprise Edition to Ruby 1.9.2.
- Optimized database performance and helped maintain consistent page load times across an order of magnitude increase in traffic.
- Scaled the platform from less than 100 locations to over 800 in less than three months.
- Designed a service-oriented architecture overhaul of the entire publishing platform.
- Participated in a company-wide effort to embrace open source and encourage employees from all departments to participate in the open-source community.
- Implemented A/B testing in consultation with marketing and editorial to gather feedback on headlines and advertising layouts.
Technologies: JavaScript, Redis, MongoDB, MySQL, Ruby on Rails (RoR), Code Review, Back-end, APIs, Third-party APIs, Mobile UX, Performance, Scalability, Sidekiq, Video Streaming, Content Delivery Networks (CDN), REST APIs, Test-driven Development (TDD), Automated Testing, Authentication, Open Source, Sinatra, GitHub, C, Single Sign-on (SSO), Amazon S3 (AWS S3), Cloud Architecture, Web Applications, Cloud Storage, Application Performance Monitoring, JSON, Software Design, REST, System Architecture, Scalable Architecture
Server Software Engineer
2006 - 2010
Apple
- Developed a Grand Central Dispatch-based web server for MacRuby called ControlTower.
- Upgraded the product for two major Rails revisions and one Ruby version.
- Managed the QA process for the team’s deliverables.
- Implemented a web interface, including a near real-time video preview system built with only HTML, CSS, and JavaScript.
- Improved server and database performance from less-than-acceptable to ready-to-release.
Technologies: SANs, Quartz Composer, C, Objective-C, Ruby on Rails (RoR), Xcode Server, Code Review, Back-end, Vanilla JS, Full-stack Development, Mobile UX, Performance, Scalability, CSS, HTML, Front-end, Video Streaming, Content Delivery Networks (CDN), Mobile Development, REST APIs, Test-driven Development (TDD), Desktop App Development, Automated Testing, Authentication, Open Source, SAML, GitHub, Single Sign-on (SSO), Web Applications, JSON, Mobile App Development, Software Design, PHP, REST, System Architecture
Experience
CityEats
CityEats was a platform for customers to make reservations at popular restaurants, and also for restaurants to manage availability and offer special reservations for promotional events. With Burnside Digital, I assisted in maintenance and the development of new features. I also led a team that re-implemented the integration between the customer-facing site and the reservation management back-end utilized by restaurants using a service-oriented architecture.
ControlTower
https://github.com/MacRuby/ControlTowerControlTower is an HTTP application server for MacRuby. As a member of the OS X Server team at Apple, I developed ControlTower to meet the needs of a larger project, as there were no existing application servers at the time that worked with MacRuby and met all of the project requirements.
Evolver
https://github.com/jballanc/EvolverEvolver is a "toy simulation" of an evolutionary system that I implemented as part of my doctoral thesis research in the field of evolutionary biology. Utilizing Ruby, it allows for all of the important parameters of the simulation to be specified via configuration file, while still running fast enough to complete simulations in a reasonable amount of time.
Y Combinator for Objective-C
https://github.com/jballanc/objc-ycombWhile studying both Objective-C and the various fixed-point combinators from the lambda calculus, I conceived of a way to utilize Objective-C's blocks to implement Y Combinator. This is more of a fun, exploratory project than something intended for production use (though there's no reason it shouldn't work in a production system).
Education
2008 - 2011
Doctorate in Computational Evolutionary Biology
Stevens Institute of Technology - New Jersey, USA
2005 - 2008
Master's Degree in Chemical Biology
Stevens Institute of Technology - New Jersey, USA
1998 - 2002
Bachelor's Degree in Chemistry
Stevens Institute of Technology - New Jersey, USA
Skills
Libraries/APIs
Node.js, React, Compojure, Rack, Sidekiq, REST APIs, Slack API, jQuery, Nokogiri, Stripe, Twilio API, Backbone.js, Shopify API, Xcode Server, X (formerly Twitter) API
Tools
Git, Vim Text Editor, Jira, GitHub, GitHub Pages, Amazon CloudWatch, Amazon Cognito, NPM, TestFlight, Auth0, ChatGPT, Terraform, Observability Tools, Notion, Bitbucket, Emacs, TextMate, GitLab, Amazon EKS, MongoDB Atlas, Expo, BigQuery, Claude, Chef, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Quartz Composer, Xcode, Mercurial, Reagent, Apache Airflow, Figma
Languages
HTML, HTML5, Java, Python, Ruby, JavaScript, C, Julia, C#, TypeScript, XML, SAML, Python 3, Swift, CSS, Objective-C, Clojure, C#.NET, GraphQL, Lua, C++, SQL, CoffeeScript, Snowflake, PHP
Frameworks
Sinatra, RubyMotion, Ruby on Rails (RoR), Django, Cocoa, WebObjects, Merb, Padrino, Tailwind CSS, Vanilla JS, React Native, .NET, Electron, Flask, NestJS, Swagger, Redux, Next.js, UIKit, Angular, Express.js, Stimulus, SwiftUI, Material UI, Jest, Spring, Hibernate, AngularJS, ClojureScript
Paradigms
API Architecture, DevOps, Gang of Four (GOF) Design Patterns, Object-oriented Programming (OOP), Agile Software Development, Agile, Mobile Development, Microservices, Test-driven Development (TDD), Automation, Desktop App Development, Model Context Protocol (MCP), Continuous Delivery (CD), REST, Functional Programming, Kanban, Scrum, Distributed Programming, Automated Testing, HIPAA Compliance, Logic Programming
Platforms
Docker, Amazon Web Services (AWS), MacOS, iOS, AWS Lambda, Firebase, Google Cloud Platform (GCP), AWS Elastic Beanstalk, Azure, Android, Linux, FreeBSD, Mobile, Vercel, OS X, Heroku, JBoss, Visual Studio Code (VS Code), Arduino
Storage
SQLite, PostgreSQL, MongoDB, Amazon DynamoDB, Cloud Firestore, NoSQL, Amazon S3 (AWS S3), JSON, Amazon Aurora, Database Structure, MySQL, Redis, Memcached
Industry Expertise
Healthcare
Other
API Design, Architecture, API Integration, APIs, Software, Back-end, Mobile App Development, Software Development, CTO, Team Leadership, Startups, Code Review, Full-stack, Full-stack Development, Software Architecture, Third-party APIs, Technical Leadership, Performance, Scalability, Amazon RDS, Serverless, Front-end, Video Streaming, API Gateways, SDKs, General Data Protection Regulation (GDPR), Authentication, OAuth, WebSockets, Open Source, Single-page Applications (SPAs), Web Scraping, Data Scraping, Single Sign-on (SSO), PDF, API Testing, Cloud Architecture, Web Applications, Cloud Storage, Application Performance Monitoring, Software Development Lifecycle (SDLC), Software Design, Integration, Cloud Infrastructure, Large Language Models (LLMs), Agentic AI, CI/CD Pipelines, Containerization, Distributed Systems, Infrastructure as Code (IaC), Monitoring, Operational Excellence, System Architecture, RESTFul APIs, Data Modeling, SaaS, Scalable Architecture, Accounting Software, Recommendation Systems, Artificial Intelligence (AI), Machine Learning, Mobile UX, Apollo, Prompt Engineering, Generative Pre-trained Transformers (GPT), Content Delivery Networks (CDN), FastAPI, Education, Leadership, Communication, OpenAI, Data Visualization, Supabase, Inventory, Inventory Management, POS, SVG, Google BigQuery, Voice, Anthropic, Fractional CTO, AI Voice Agents, Conversational AI, Natural Language Processing (NLP), VoiceBot, Generative Artificial Intelligence (GenAI), SANs, Code Architecture, Datomic, API Hooking, A/B Testing, Product Management, SOAP, Chemistry, Pinecone, Poetry, Animation, Open-source LLMs, Speech-to-Text (STT), Text-to-Speech (TTS)
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