SellTheFlip.com

Overview

SellTheFlip is a SaaS platform built for online resellers who manage inventory across multiple marketplaces. It automates the tedious process of cross-listing items, managing pricing, and tracking sales across platforms like eBay, Poshmark, and Mercari.

Impact

• Designed and shipped a full-stack SaaS product from idea to paying customers
• Built cross-listing automation reducing listing time by 70% per item
• Grew to hundreds of active users through organic search and word of mouth
• Integrated with eBay, Poshmark, Mercari, and other major resale marketplaces

Technical Challenges

• Reverse-engineering marketplace APIs and handling inconsistent data formats across platforms with varying rate limits and authentication methods.
• Designing a unified product data model that could represent items across marketplaces with different category taxonomies and attribute requirements.
• Building a reliable background job system for bulk listing operations while providing real-time progress feedback to users.

Technologies