Janwel Josh B. Sebastian
AI Tools Developer | Marketing Operations Specialist | E-Commerce Automation
E-Commerce Operations 2+ Years Experience Amazon Seller Central Claude AI | ChatGPT Python Scripting

About me

Results-driven AI Tools Developer and Marketing Operations Specialist with over two years of experience in e-commerce data management, workflow automation, and AI-assisted tool development. Proven ability to bridge the gap between non-technical teams and AI technology by designing practical, accurate, and impactful tools without a formal programming background.

Core Skills and Expertise

AI TOOLING

Prompt engineering and ChatGPT/Claude-assisted tool development

AUTOMATION

Python scripting and workflow automation, AI-assisted development

E-COMMERCE

Amazon Seller Central and e-commerce product listing operations

DATA VALIDATION

Fitment and compatibility data processing, validation, and format conversion

QUALITY CHECK

Product image QA — orientation, product validation, logo and reflection checks

TOOL BUILD

Internal browser-based and desktop tool development (HTML, Python)

CONTENT GENERATION

Content generation and product listing optimization

ENABLEMENT

Team consulting and knowledge transfer on AI-assisted workflows

Software

Amazon Seller Central Channel Advisor ChatGPT Claude AI Hermes Discord Bot MS Excel Python VS Code Shopify

Work History

Core AI Team Member Current Role

KarParts360 — Remote, Philippines | April 3, 2026 – Present

  • Develop Python scripts and AI-assisted tools using Claude to automate workflows previously handled by a much larger workforce.
  • Build accurate, reliable automation as an alternative to fully agentic AI approaches, prioritizing cost-efficiency, output quality, and consistency.
  • Consult with team members on effective AI prompting strategies and tool design for internal process automation.
Data Team Staff – Marketing Department Previous Role

KarParts360 — Remote, Philippines | August 12, 2024 – April 2, 2026

  • Performed QA of product listings, filtering out incorrect formats, improperly edited images, and fitment inaccuracies.
  • Researched correct product positioning and reported findings to the Graphics Team for image corrections.
  • Built and maintained internal tools widely used across teams, including fitment processors and image-related tools.
  • Served as internal consultant for AI tool creation; transitioned tooling from HTML-based interfaces into Python desktop apps and Discord bot automation.

Projects Worked On:

  • Managed product listings for a different store using Shopify. Developed an HTML tool that creates a CSV file that can easily be imported into Shopify to create product listings.
  • Helped develop a Python web scraping automation for fitment data collection from a supplier website.
EU Staff – Enhancement Unit Starting Role

KarParts360 — Remote, Philippines | May 31, 2024 – Aug 11, 2024

  • Collected product data and images for new listings across multiple supplier websites.
  • Validated fitment formats and counts, cross-referencing against supplier data for accuracy.
  • Identified manual copy-paste of fitment data as a major bottleneck, then independently built the first internal Fitment Processor using ChatGPT prompt engineering.

Sample Tools I Built

Custom AI-assisted HTML tools that I developed using Claude, aiming to improve team efficiency and listing accuracy.

*Brand identifiers are crossed out for confidentiality

Sample Tool No. 1
Fitment Processor

A custom browser-based tool built in HTML that lets the user copy fitment data from a supplier website to perform a cross-reference against an uploaded Excel file. This tool helped employees who struggled with opening large Excel files — it displays all related results found in the uploaded file, which the user can copy and re-process to get the final result.

Fitment Processor tool screenshot

Live tool screenshot shows the supplier website (left) and the tool (right). Two pieces of data are copied and pasted into the tool, then the results are displayed at the bottom. A separate copy button is also available for the header, in case only a specific header is needed.

** This is from a different supplier website

Supplier website to Fitment Format Generator Tool

Live tool screenshot shows the supplier website (left) and a Fitment Format Generator Tool (right). The sample fitment is copied and pasted into the tool, which then generates an acceptable format ready to be pasted into the main Fitment Processor.

Result pasted into Main Fitment Processor

Live tool screenshot shows the result from the Fitment Format Generator Tool (left) copied and pasted into the Main Fitment Processor (right), with the generated results found from the input data.

** This is from a different supplier website

Second supplier website to Fitment Format Generator Tool

Live tool screenshot shows another supplier website (left) and the Fitment Format Generator Tool (right). The sample fitment is copied and pasted into the tool, which then generates an acceptable format ready to be pasted into the main Fitment Processor.

Second result pasted into Main Fitment Processor

Live tool screenshot shows the result from the Fitment Format Generator Tool (left) copied and pasted into the Main Fitment Processor (right), with the generated results found from the input data.

Sample Tool No. 2
Image Renaming Tool

A custom browser-based tool built in HTML that lets the user input the desired file name and upload images in the correct order. Users can also independently set the image version needed. This tool is far more time-efficient than manually renaming each image, and generates an Excel tracking table at the bottom for easy copy-paste into Excel trackers, marked "YES" for completed renames.

Image Renaming Tool interface

Live tool screenshot shows the source images (left) uploaded into the Image Renaming Tool (right) along with the desired Unique ID that will be used as the new file name, plus the generated Excel tracking row at the bottom.

Final renamed image files

The final renamed image files after processing. The first image uses the "masterbo" naming format — the designated master image for the set.

Sample Tool No. 3
Export File Converter Tool

A custom browser-based tool built in HTML that lets the user input an exported file from a third-party website and converts it into the format the user actually needs.

Export File Converter Tool before upload

The tool's default display before any file is uploaded.

Export File Converter Tool after upload with results

After a file is uploaded, results are displayed. Valid SKUs are shown as ready to convert with no problems, while entries flagged under "Body Type" indicate that the make/model combination doesn't exist in the available fitment format.

Sample Tool No. 4
A+ Content Generator Tool

A custom browser-based tool built in HTML that lets the user upload the processed file from the Export File Converter Tool. This tool generates A+ Content ready to be uploaded to Amazon.

A+ Content Generator Tool screenshot

Live tool screenshot shows the tool generating A+ Content based on the Partslink number entered from the converted CA export file. Each Partslink follows a different format depending on its specs and details, and the compatibility table is pulled directly from the file and generated as its own card. Some cards may appear incomplete — that's intentional, since it's the graphics/design team's task to fill in the remaining visual elements for those cards.