Allan Farinas, Developer in Pasadena, CA, United States
Allan is currently unavailable

Allan Farinas

Software Engineer and Developer

Pasadena, CA, United States

Toptal member since February 27, 2026

Expertise
Full-stackRubyREST APIArtificial IntelligenceDatabaseRedisPostgreSQLReact.jsPythonAgile DevelopmentTypeScriptSQLAlgorithmsApache Kafka
Bio

Allan is a back-end and full-stack developer with over 10 years of experience building and designing performant APIs and scaling complex applications. He specializes in Ruby/Rails, Python, and React. Allan is passionate about performance, optimization, and building great user experiences.

Portfolio

CareRev
Ruby, Ruby on Rails 8, PostgreSQL 10, PostgreSQL, Redis, Sidekiq, Apache Kafka...
AMN Healthcare
Ruby, Ruby on Rails 6, PostgreSQL 10, PostgreSQL 9, Python 3, FastAPI, MongoDB...
Revolution Prep
Ruby, Ruby on Rails 5, AngularJS, Angular, PostgreSQL, PostgreSQL 9, JavaScript...

Experience

  • Ruby - 10 years
  • Ruby on Rails 8 - 10 years
  • Redis - 9 years
  • PostgreSQL 10 - 8 years
  • TypeScript 5 - 7 years
  • Sidekiq - 7 years
  • React - 7 years
  • Python 3 - 5 years

Preferred Environment

Ruby, Ruby on Rails 8, Python 3, React, TypeScript 5, PostgreSQL 10, Redis, Sidekiq, Apache Kafka, AWS Lambda

The most amazing...

...facility-level configuration system I've built at CareRev supported multi-tenant permissions for over 50,000 users.

Work Experience

Senior Back-end Software Engineer

2021 - 2025
CareRev
  • Designed, implemented, and led a project to support custom credential types, streamlining the onboarding and credentialing process by being back-end driven and reducing the need for client-side updates using Ruby on Rails.
  • Automated compliance checks by integrating the OIG exclusion database via Python and Selenium, saving 25 hours/month in manual audits.
  • Identified and resolved a critical bug related to Dropbox Sign, reducing signature request failures by 87% and improving quota management efficiency.
  • Built a facility-level configuration system to support multi-tiered permissions using Apache Kafka and Ruby on Rails, enabling flexible user role management for over 50,000+ users.
  • Eliminated operations' reliance on spreadsheets by building in-app workflows for background checks and credential tracking, saving 20+ hours/week.
Technologies: Ruby, Ruby on Rails 8, PostgreSQL 10, PostgreSQL, Redis, Sidekiq, Apache Kafka, Python 3, React, TypeScript 5, TypeScript 3, TypeScript, Unit Testing, Continuous Integration (CI), Continuous Delivery (CD), SQLAlchemy, Ruby on Rails (RoR), Ruby on Rails API, REST APIs, Python, Architecture, Full-stack, Technical Leadership, HIPAA, HIPAA Electronic Data Interchange (EDI), HIPAA Compliance, Artificial Intelligence (AI), Health, Healthtech

Software Engineer, Team Lead

2019 - 2021
AMN Healthcare
  • Created features for a secure, HIPAA-compliant health document logging system using Ruby on Rails and React, enabling secure, efficient, and auditable record-keeping for 500+ medical providers.
  • Built a scalable microservice for automatically generating pre-filled, custom medical documents for insurance payers using Python and FastAPI, reducing manual insurance paper workload by 70%.
  • Developed and maintained FlipperJS, an internal tool to access back-end feature flags via the global Redux store.
  • Led and mentored a team of 4 engineers, which resulted in a 25% improvement in sprint velocity.
Technologies: Ruby, Ruby on Rails 6, PostgreSQL 10, PostgreSQL 9, Python 3, FastAPI, MongoDB, React, TypeScript 4, TypeScript 3, TypeScript, Unit Testing, Continuous Integration (CI), Continuous Delivery (CD), SQLAlchemy, Ruby on Rails (RoR), Ruby on Rails API, REST APIs, PostgreSQL, Python, Architecture, Full-stack, Technical Leadership, HIPAA, HIPAA Electronic Data Interchange (EDI), HIPAA Compliance, Health, Healthtech

Full-stack Software Engineer

2017 - 2019
Revolution Prep
  • Developed and created tests for features used by students and tutors using Ruby on Rails and Angular.
  • Added i18n support for international students, expanding platform access to 5 markets.
  • Leveraged Redis cache storage to decrease load times on consumer-facing pages by 40%.
Technologies: Ruby, Ruby on Rails 5, AngularJS, Angular, PostgreSQL, PostgreSQL 9, JavaScript, Internationalization, Redis, Sidekiq, WebSockets, Unit Testing, Continuous Integration (CI), Continuous Delivery (CD), Ruby on Rails (RoR), Ruby on Rails API, REST APIs, Architecture, Full-stack

Full-stack Software Engineer

2014 - 2017
Unbooked
  • Developed scheduling features using ASP.NET and DayPilot for client service management.
  • Created a production pricing algorithm that dynamically adjusted service prices based on peak hours, improving utilization and revenue efficiency.
  • Optimized database performance by replacing inefficient LINQ queries with SQL stored procedures, reducing load times by 30%.
Technologies: ASP.NET, MySQL, SQL, LINQ, LINQ to SQL, C#, C#.NET, Unit Testing, Continuous Integration (CI), Continuous Delivery (CD), REST APIs, Full-stack

Ground Systems Engineer Intern

2013 - 2013
NASA Jet Propulsion Laboratory
  • Developed scripts to export and extract metadata from systems models/diagrams using Python and MagicDrawOpenAPI.
  • Built a web app to navigate the ground systems engineering models and diagrams, increasing accessibility for mission-critical teams.
  • Worked directly with ground systems stakeholders to gather requirements.
Technologies: Python, Business Process Modeling Notation (BPMN), HTML, CSS3, JavaScript

Experience

MusicProg

https://www.musicprog.com/
A web app used to help teach music theory through chord progressions. This is primarily for music producers who don't have the fundamental music theory knowledge but want to create better chord progressions.

Restaurant Recommender AI Agent

https://github.com/alpha-san/restaurant_recommender_ai_agent
A web app that recommends restaurants based on the location and food preferences of its users. It has a stored memory that can automatically construct contexts and use different tools based on user input. It requires a Gemini API key.

KakugoSearch

https://github.com/alpha-san/kakugosearch
An open-source search engine that offers hybrid search using full-text search and natural language. It offers plug-and-play LLM support. It's built on Tantivy's full text searching via Rust for performance and a Python sidecar for AI implementation. Searching happens in a two-stage architecture/phases, where the first stage is full-text search via inverted indexes, and then the second stage is AI reranking. It only supports Rails integration at the moment, but I'm also working on a Python wrapper.

Education

2011 - 2014

Bachelor's Degree in Computer Science

California State Polytechnic University, Pomona - Pomona, CA, USA

Skills

Libraries/APIs

Ruby on Rails API, REST APIs, React, Sidekiq, SQLAlchemy, LINQ

Tools

LINQ to SQL

Languages

Ruby, Python 3, TypeScript 5, Python, TypeScript, TypeScript 4, JavaScript, SQL, C#, C#.NET, HTML, CSS3, TypeScript 3

Frameworks

Ruby on Rails (RoR), Ruby on Rails 6, Ruby on Rails 5, AngularJS, Angular, ASP.NET, Flask

Paradigms

Unit Testing, HIPAA Compliance, Continuous Delivery (CD), Continuous Integration (CI), Compiler Design, Business Process Modeling Notation (BPMN)

Storage

PostgreSQL 10, Redis, Databases, PostgreSQL, MongoDB, MySQL

Platforms

Apache Kafka, AWS Lambda

Other

Ruby on Rails 8, Architecture, Full-stack, Technical Leadership, HIPAA, HIPAA Electronic Data Interchange (EDI), Health, Healthtech, Data Structures, FastAPI, Artificial Intelligence (AI), Algorithms, Software Engineering, Numerical Analysis, Operations Research, Computer Architecture, Operating Systems, PostgreSQL 9, Internationalization, WebSockets, Search

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