How eBay's Cassini Search Algorithm Affects Your Listings

What Cassini Is and Why It Matters

Cassini is eBay's search engine. When a buyer types something into the eBay search bar, Cassini decides which listings show up first. If your listing is on page five of search results, it might as well not exist. Most buyers never scroll past the first two pages.

eBay does not publish the exact formula Cassini uses to rank listings. But over the years, sellers and eBay themselves have confirmed several factors that influence where your listing appears in search results. Understanding these factors is not about gaming the system. It is about making your listings as complete and buyer-friendly as possible, which is exactly what Cassini is designed to reward.

I am not going to pretend to have some secret inside knowledge of Cassini. What I can share is what has consistently worked for sellers I have talked to over 18 years of running eCommercePlayer, combined with what eBay has publicly stated about how their search works.

Item Specifics: The Biggest Factor You Control

Item specifics are structured data fields that eBay provides for each category: Brand, Color, Size, Material, Model Number, and dozens of others depending on what you are selling. When a buyer searches for 'blue Nike running shoes size 10,' Cassini matches those terms primarily against item specifics, not your title or description.

Fill in every single item specific that eBay offers for your category. Not just the required ones. All of them. Every optional field you complete gives Cassini another data point to match your listing against buyer searches. Leaving fields blank means your listing will not appear when buyers use those filters.

eBay has been increasingly aggressive about surfacing item specifics in search. They added aspect-based filtering several years ago, which lets buyers narrow results by clicking on specific attributes. If your listing does not have those attributes filled in, it gets filtered out entirely.

This is the single highest-return activity you can do per listing. It takes two extra minutes and directly affects whether buyers can find your product.

Listing Quality: Titles and Descriptions

Your listing title should be clear and descriptive, not stuffed with keywords. Cassini can tell the difference between a natural title and keyword spam, and keyword-stuffed titles also turn off buyers. Write a title that accurately describes your product using the terms a buyer would actually search for.

For example, 'Sony WH-1000XM5 Wireless Noise Canceling Headphones Black' is a good title. 'AMAZING Sony Headphones WH1000XM5 BEST DEAL Noise Cancel Wireless BLACK L@@K' is a bad title. Cassini may penalize the second one, and buyers definitely judge it.

Your description should be structured and informative. Use clear sections, bullet points, and put the most important information first. Cassini indexes your description text, so include relevant terms naturally. But do not repeat keywords artificially. Write for the buyer first, search engine second.

Photos matter for listing quality too. eBay recommends at least 5 photos per listing, and listings with more photos tend to rank better. Use clear, well-lit photos that show the product from multiple angles. The first photo is especially important because it appears in search results.

Seller Performance Signals

Cassini factors in your performance as a seller. This includes your defect rate, late shipment rate, cases closed without seller resolution, and overall feedback score. eBay wants to show buyers listings from sellers who will deliver a good experience.

This means the basics matter: ship on time, describe your items accurately, respond to buyer messages quickly, and handle returns professionally. A seller with a 99.5% positive feedback score and zero defects will rank better than a seller with 95% feedback and recent defects, all else being equal.

Shipping speed is increasingly important. eBay has been pushing fast and free shipping for years. Listings that offer free shipping and same-day or one-day handling time tend to get a ranking boost. If you cannot offer free shipping, at least keep your handling time to one business day.

These are not quick fixes. Building a strong seller performance record takes time and consistency. But the ranking benefit compounds. A strong track record gives every listing you create a baseline advantage in search.

Buyer Engagement: The Signal You Influence Indirectly

Cassini tracks how buyers interact with listings. Click-through rate from search results, time spent on the listing page, watch list additions, and conversion rate all send signals about listing quality. A listing that buyers click on, spend time reading, and frequently purchase ranks higher over time.

You cannot directly control whether a buyer adds your item to their watch list. But you can influence it by creating listings that are compelling enough to hold a buyer's attention. Good photos, clear descriptions, competitive pricing, and multimedia content all contribute to keeping buyers on your page longer.

This is where video and audio can make a meaningful difference. A buyer who watches a 45-second product video on your listing page is spending significantly more time engaged with your listing than a buyer who glances at photos and moves on. That time-on-page signal tells Cassini that your listing is providing value to buyers.

eCommercePlayer's play count analytics show that listings with embedded video players consistently get clicks from buyers. Each of those interactions is a potential engagement signal. I am not claiming that video is a magic ranking factor, but anything that keeps buyers engaged with your listing longer is working in your favor.

Watch list additions are another strong signal. Buyers add items to their watch list when they are seriously considering a purchase. Listings that generate more watch list adds tend to maintain or improve their search position over time.

What You Can Actually Do About All This

Here is a practical checklist based on everything above. You can go through your active listings today and start making improvements.

First, audit your item specifics. Open each listing and fill in every optional field. This is the fastest win available. Second, review your titles. Remove all-caps words, excessive punctuation, and keyword stuffing. Write a clear, accurate title using normal language. Third, restructure your descriptions. Add headers, bullet points, and put the most important details at the top. Remove any walls of unformatted text.

Fourth, check your photos. Make sure each listing has at least 5 clear, well-lit images. If any photos are dark or blurry, reshoot them. Fifth, add video or audio where it makes sense. This is especially important for used items, electronics, instruments, and anything where condition or functionality matters. Upload to eCommercePlayer and embed the player thumbnail using the image-link method.

Sixth, look at your seller metrics in Seller Hub. If your defect rate or late shipment rate is above zero, fix the underlying issues. Respond to messages within 24 hours. Ship within your stated handling time, every time.

None of these steps are complicated. But doing all of them consistently across your listings puts you ahead of the majority of sellers who skip one or more of them. Cassini rewards completeness and quality. Give it what it wants and your listings will be easier for buyers to find.