Wk5: “Crosslister” – Kickoff
November 1, 2026 Leave a Comment
November 1, 2026 – how is it November already?!
For Week 5 of One Project Every Week, I’m working on Crosslister. That’s the working name. We’ll worry about naming it once it earns one.
The idea: Sell everywhere from one “home” marketplace.
Two sellers; same-ish problem
I’ve always thrifted, mostly for myself. I enjoy finding something interesting, useful, or overlooked.
Sometimes a janky Jensen tape player to load software onto ancient computers…
Over the last few years, I started buying with resale in mind, with reasonable success. I sell on eBay: toys, games, vintage software, and whatever else seemed like a good idea at the moment I bought it. Some inventory is listed. Some lives only in a spreadsheet and a pile in my basement, patiently waiting for me to become a more organized person.
Finding things worth selling is the fun part, I truly enjoy the thrill of the hunt. Getting everything listed and keeping track of it, and actually selling it for a profit is where the work piles up.
Sherry has more than 400 active listings on Poshmark. She puts real work into the photographs, descriptions, and details. Getting those products onto another marketplace means doing much of that work again.

We both want more sales but less work required to get them.
There are existing tools for this. For our volume, they can feel expensive, cumbersome, or like another system that needs feeding. A side hustle should not require its own side hustle to operate.
One catalog, multiple selling channels
Crosslister will maintain one product record, then adapt it to the marketplaces where it belongs.
Sherry’s first path is Poshmark to eBay. Mine is eBay to Amazon.

Member since 1998. I’m old!
Poshmark has made poor product decisions over the years, and still does not provide programmatic access to their system like other marketplaces do. They value user engagement, but optimizing for engagement in a way that makes sellers spend all damn day sharing, liking, and following products doesn’t help you sell anymore.
Sherry’s original photographs and carefully written descriptions stay intact. Each marketplace gets the details it needs. Cost, fees, shipping, and expected profit should be available when we make pricing decisions.
And when something sells, the other listings need to come down. Selling the same one-of-a-kind item twice is a fairly efficient way to disappoint two people. Or even worse, get dinged on the strict seller performance metrics and lose your advantage.
That coordination is central to the product.
Less work, fewer decisions
I also want Crosslister to help answer a practical question: What should I do next?
An item has been sitting for months. Would a lower price still leave a reasonable profit? Is something ready to list on another channel? Is one missing detail blocking a whole group of products?
Show me the item, the reason, the economics, and a useful action. Let me decide, then handle the work.
I don’t need another dashboard to admire. I need a shorter to-do list.
Built with AI, but no AI inside (yet).
This project will be built through the same collaboration I’ve used for the first four weeks.
But Crosslister itself doesn’t need AI-generated descriptions or a chatbot. Sherry already wrote her listings. Preserving her work matters more than generating more words. Frankly the AI descriptions she gets from Poshmark are not very good. Plus I truly believe people will start to recognize AI content and become blind to it. Like “Banner Blindness” for ads, but “AI Blindness” for content.
The first recommendations can come from straightforward rules and actual inventory data. Sometimes the useful thing is knowing what not to add.
What counts as success?
A polished screen won’t prove this works. Neither will importing a few hundred records, or connecting to an API.
The test is can we get sales on new channels, or more sales on existing ones, by following system nudges a la Selling Coach in Seller Central – which I happen to know a lot about ;)
The system has to manage state, especially when something sells to ensure we don’t have cross-marketplace sales conflicts.
Marketplace connections, approvals, and different listing requirements make this a more ambitious week. The challenge is getting the whole process to work with real accounts and real inventory, without making me the permanent meat puppet between systems.
We’re starting with two sellers we know very well.
Let’s see whether thwe can help them sell something.











