Principal Developer Business Intelligence
Resume:
Jonathan Karlen
Principal Developer
*** ***** **** *****, *******, United States, 63366
***@******.***
Principal Developer with over 20 years of extensive expertise in infrastructure as code, performance tuning, and agile methodologies. Demonstrates a strong technical leadership and system architecture background, with a proven track record in developing advanced AI and software solutions. Passionate about leveraging innovative technologies to enhance business intelligence and data security, while continuously seeking opportunities for growth and improvement in software development practices. Employment history
Principal Developer,
Golden Hippo, 2024 -
2025
Los Angeles, CA
• Led development and optimization of high-traffic Node.js and Angular applications hosted on Heroku, ensuring scalability and performance.
• Spearheaded build optimization initiatives across multiple brands, addressing dependency management, Redis performance, and Heroku stack migrations.
• Conducted in-depth technical assessments of legacy apps (including Ionic/3 and Angular/5) to mitigate security and performance risks.
• Refactored key features in loyalty and rewards platforms, improving point calculations, multipliers, and tracking mechanisms.
• Modernized charting and data visualization tools by transitioning from outdated libraries to D3.js, enhancing user experience and interactivity.
• Investigated and resolved complex PostgreSQL and MySQL performance bottlenecks, optimizing queries and indexing strategies.
• Led initiatives to streamline queuing systems, evaluating migration from PostgreSQL-based queues to Kafka for event-driven processing.
• Diagnosed and resolved infrastructure issues, including ALB timeouts, CORS errors, and deployment pipeline inefficiencies.
• Managed and mentored developers, improving team efficiency, knowledge-sharing, and best practices in CI/CD workflows.
Senior Developer,
South California Gas,
2023 - 2024
Los Angeles, CA
• Worked on the Applied AI Search team to develop a search application for Corporate Compliance to search hundreds of thousands of documents.
• Wrote C# endpoints to consume the Azure OpenAI API for generating document embeddings and returning cached document summaries.
• Developed Python interceptors and effects in the document ingestion pipeline to extract textual content from various file types (Outlook MSG, MS Word, Excel, Text, EML files).
• Created Python scripts to interact with Azure OpenAI’s Completion API for generating document summaries.
• Contributed to the Terraform repository to manage a complex array of Azure resources.
• Developed deployment pipelines for Azure and GitHub Actions.
• Trained an Azure Document Intelligence model to process information request documents and identify questions within them.
Worked closely with cross-functional teams to troubleshoot and enhance e-commerce and subscription-based platforms.Led architectural redesign of legacy systems at Golden Hippo, implementing microservices architecture that reduced deployment time by 37% and enhanced system resilience.
Spearheaded cross-functional development teams at Golden Hippo, delivering mission- critical applications with 99.9% uptime while reducing technical debt by 42%. Employment history
• Leveraged various Azure services, including Document Intelligence, Storage Accounts, Azure OpenAI, AI Search Services, Key Vault, Azure PostgreSQL, Azure Cosmos DB, Pipelines, and DevOps.
• Integrated Liquibase into the deployment pipeline.
• Used BAZEL for dependency management and Test-Driven Development (TDD). Senior Developer, HD
Supply (Division of
Home Depot), 2023
Atlanta, GA
• Supported the issuance of HD Supply cards, building out full-stack applications for credit applications, card requests, posting charges, and reporting.
• Utilized microservice architecture with Docker and Jenkins for single responsibility development.
• Created new endpoints in Java and C# (.NET Core).
• Developed UI using Angular and Tailwind.
• Built an ETL application in C# for retrieving and posting online and in-store sales to customer accounts.
• Worked with the large and complicated data model generated by in-store transactions to manipulate transactional data.
Senior Software
Developer, Technology
Partners, 2020 - 2023
Chesterfield, MO
• Led software development for various nonprofit and for-profit clients across multiple industries.
• Managed multiple development projects simultaneously for IT consulting firms, ensuring delivery on time, on budget, and aligned with client requirements. Client Highlights:
• Maritz: Developed the MS Teams app for their flagship CultureNext product using NodeJS, React, Tailwind CSS, and Maritz’s REST API.
• Navigate STL Schools: Built a PHP 8.1 application with Laravel and Vue, leveraging MySQL, Redis, and Elastic Search, deployed to Digital Ocean.
• Point Recognition: Developed an employee recognition platform using .NET Core, Entity Framework, Angular, and MS SQL Server, deployed to Azure serverless environment.
• Blueprint4: Created a searchable database of youth enrichment programs using Grails/Groovy, deployed to AWS.
• RxOutreach: Developed applications for a non-profit division of ExpressScripts using Java and Oracle.
• Washington University St. Louis: Built a Covid contact tracing app using Python and Angular, deployed in Google Cloud.
Senior Software
Architect & Principal
Developer, The Shade
Store, 2007 - 2022
New York, NY
• Played a critical role in designing and delivering technology that enabled growth from a startup to a $1B company.
• Designed and developed a scalable core CRM platform (PHP/mySQL), managing $1B in annual transactions.
• Facilitated transition to in-house production, building a manufacturing tracking system.
• Integrated systems with key partners (FedEx, UPS) and various tax platforms.
• Ensured business continuity through strategic engagement with senior leadership.
• Developed a mobile commerce experience using React.
• Led a team of 20 engineers and represented the company in funding audits.
• Created a flexible Docker-based microservice architecture to re-engineer a monolith to create a domain-driven methodology to integrate with inventory, invoicing, financial data (to drive pricing and availability) with PHP 8.1.
Employment history
• Architected an efficient and scalable data model consisting of over 700 tables with proper normalization and indexing leveraging primary/foreign keys, singular indices and compound indices.
• Developed a complex JSON model for receiving and processing orders which enabled retailers such as Crate & Barrel to submit orders. The e-commerce website also leveraged this model to submit internal orders as well.
• Integrated with numerous suppliers to give internal purchasing team real-time insight into available and pricing of materials.
• Created extensive reporting and KPI dashboards to aid stakeholders. Chief Executive Officer,
Karlen Group, 2007 -
2015
O’Fallon, MO
• Led strategic direction and IT operations for an independent consulting firm.
• Drove business development by delivering impactful customer experiences.
• Developed numerous applications for business customers using emerging technologies. Client Highlights:
• The Incentive Group: Built the client’s flagship product, inGauge, using Ruby on Rails, integrated with Salesforce and customer APIs, deployed at AWS.
• SpaceSculpt (defunct): Developed a SaaS product for interior designers using Ruby on Rails. Skills
Infrastructure as Code Performance Tuning Business Intelligence Agile Methodologies Technical Leadership System Architecture Data Security Code Review Software Testing User Authentication Deployment Pipelines ETL Development Data Extraction Software Architecture Cloud Services Cloud Migration Performance Monitoring Data Migration System Design Cloud Strategy Software Development API Development Microservices Test-Driven Development Containerization Node.js C# Angular
React PHP mySQL PostGres
Heroku Azure AWS GCP
Full Stack Java Gradle JavaScript
TypeScript
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