Python Developer Senior

Daniel Llerena

New Jersey 973-***-**** *****************@*****.*** linkedin.com/in/daniel-llerena-bb6611149 SENIOR PYTHON DEVELOPER

PROFESSIONAL EXPERIENCE

Common Cents Distributors Lead Python Developer Fairfield, NJ 03/2018 - 05/2025

● Led the end-to-end development of a custom internal UI to streamline supplier catalog analysis, order creation, product scanning, picking, production, and shipping processes for employees.

● Created an entire MySQL DB with AWS RDS which acted as the backbone to the UI that the buyers and warehouse managers/users used to purchase products, scan in products, package products into listings that can be sold on amazon, and ship truckloads of pallets of products.

● Led team to create a fully-fledged warehouse system that handles breaking down pallets, scanning in pallets with pack ID's and scanning in products on those pallets while using various units of measure such as individual units, ounces, pounds, sleeves and cases. The backend web integrations worked with the internal android app API to update the DB through internal API connections.

● Handled large datasets of uploaded catalog sheets from Vendors and Suppliers, retrieving the UPC's (Universal Product Codes), cost, discounts, case size information and more. Then integrated this software with SPAPI (Selling Partner API), to pull the current listing price information from amazon and calculate the profits and profit margin based on the supplier cost and output to the internal UI this information so the buyers could use this information to purchase products that could be packaged into listings that sell well on amazon. Used Pandas and NumPy to optimize iterating through this data to optimally break down the data and use it for market analysis.

● Created AWS EC2 Servers for Development, Staging and Production Environments.

● Developed a Database Interface system to work with PYODBC to work with a 3rd party database warehouse system using old 2003 DB technology. This system allowed daily tasks in the form of cronjobs to seamlessly interact with a Windows RDS server and update the data in the 3rd party integration, meeting the demands for internal warehouse operations.

● Worked with countless API's such as Amazon, Walmart, Keepa and Feedvisor, and handled migration between deprecated version to current of Amazon MWS to SPAPI.

● Handled setup and deployment for development, staging and production servers to work with AWS Code Pipelines allowing for automatic and seamless deployment. This was a transition from Jenkins which was originally used.

● Handled day-to-day issues brought up by buyers and warehouse managers and deployed hotfixes / data corrections for user-issues and system-issues. SKILLS

Languages, Frameworks, & Tech:

Python, Pandas, Numpy, mySQL, PostgreSQL, Redis, RESTful APIs, API Integration DevOps/Cloud:

AWS (EC2, S3, RDS, Lambda), Docker, Jenkins, AWS CodePipeline, AWS Codebuild, SSH Tools & Platforms:

Git, Github, Bash, Linux, Jira, Monday

EDUCATION

University of William Paterson B.S. Computer Science Wayne, NJ 05/2016