eBay SEO in 2026: How the Cassini Algorithm Ranks Your Listings
By Gulfam Haidar, Founder, GrowEventure. Last updated September 2026.
Ebay Cassini Algorithm: quick summary
In short, this guide covers ebay cassini algorithm in plain terms. Below you will find the key points on ebay cassini algorithm, a breakdown you can act on today, and clear answers to the most common questions about ebay cassini algorithm.
Cassini is eBay’s search engine, and it ranks listings in Best Match by relevance, listing quality, price, seller performance, and sell-through rate. To rank higher in 2026, fill every item specific, write keyword-rich but readable titles, price competitively, keep Top Rated Seller status, and use Promoted Listings to boost visibility while your organic rank builds. Item specifics and sell-through rate are the two levers that move rank most. (Source: eBay Seller Center; eBay Best Match documentation.)
If your eBay listings have gone quiet, the problem is almost always that Cassini does not see them as relevant, high-quality, or proven to sell. This guide explains what Cassini actually weighs, why item specifics matter so much, and gives you a repeatable checklist to lift existing listings.
What Cassini is and how it differs from Best Match
People use “Cassini” and “Best Match” as if they mean the same thing, but they do not. Cassini is the search engine, the system that reads a buyer’s query and decides which listings to show and in what order. Best Match is the default sort order that Cassini powers, the one nearly every buyer sees when they search.
So when you optimize for Best Match, you are really optimizing for Cassini. The engine looks at the buyer’s search, matches it against your listing’s content and data, and ranks the results by how relevant and how likely to sell each one is. Understanding that Cassini is trying to predict a sale, not just match words, is the key to ranking. It favors listings that convert, not just listings that mention the right keyword.
The core ranking factors
Cassini weighs several signals together. No single one wins alone, but these are the ones that matter most.
- Relevance. How well your title and item specifics match the buyer’s search. This is the foundation. If Cassini cannot tell your listing fits the query, nothing else helps.
- Price. How your price compares to similar listings. Competitive pricing lifts rank because it lifts the chance of a sale.
- Listing quality. Complete details, clear photos, and a structured description that gives buyers what they need to decide.
- Seller performance. Your track record on shipping speed, defect rate, and returns. Cassini trusts sellers who deliver.
- Sell-through rate. The ratio of units sold to units listed. A listing that sells often signals to Cassini that buyers want it, so it ranks higher.
Think of these as a stack. Relevance gets you into consideration. Price, quality, and performance improve your position. Sell-through rate proves you belong there.
The Cassini ranking factors shown as a weighted stack, from relevance at the base through price, listing quality, and seller performance, up to sell-through rate. Title: “What Cassini Weighs When Ranking Your Listing.”
Item specifics: the biggest lever
If you fix one thing on your eBay listings, fix item specifics. These are the structured attributes eBay asks you to fill in: brand, size, color, material, model, and the many fields specific to each category. They do more work than almost any other part of your listing.
Item specifics drive ranking two ways. First, relevance. Cassini reads these fields to understand exactly what your product is and matches them against buyer searches, including searches for specific attributes. A listing with brand, size, and material filled in matches far more queries than one with blank fields. Second, filtered discovery. When a buyer narrows results using the filters on the left of the search page, eBay uses your item specifics to decide whether your listing appears. Leave a field blank, and you vanish from every buyer who filters on it.
Most stagnant listings have gaps here. Fill every applicable item specific, not just the required ones. eBay tells you which fields buyers use most in a category, and completing those is among the fastest ranking wins available. It costs nothing but a few minutes per listing.
Titles and listing content
Your title is prime keyword space. Use all of it, but write for a human first. Lead with the words a buyer would actually search: brand, product type, model, and key attributes. Include synonyms a buyer might use, but do not stuff the title with repeated or irrelevant terms. Cassini and buyers both penalize a title that reads like a keyword list. A clear title that names the product well beats a crammed one.
Photos carry weight too. Clear, well-lit images from multiple angles raise listing quality and lift conversion, and conversion feeds sell-through, which feeds rank. Use eBay’s recommended image size and count, and show the product against a clean background.
Structure your description so a buyer can scan it. Lead with the essentials, use short paragraphs or bullet points, and answer the questions a buyer would ask before buying. A description that removes doubt drives the sale, and sales are what Cassini rewards.
Seller performance and Top Rated Seller
Cassini trusts sellers who deliver, and it shows that trust in rank. Your seller performance comes down to a few metrics: shipping on time, keeping your defect rate low, and handling returns well. Slip on these and Cassini pushes your listings down, regardless of how good the listing itself is.
Top Rated Seller status is eBay’s recognition of consistently strong performance. Earning it brings two benefits that compound. First, a ranking and visibility advantage, since eBay favors trusted sellers. Second, fee benefits, including discounts that improve your margin. The requirements center on meeting shipping, defect, and service standards over a set period. Hitting them is worth the discipline, because the status pays back in both rank and cost.
Fast, tracked shipping and a clear, fair returns policy are the practical core. They protect your metrics, which protects your rank.
Sell-through rate and pricing
Sell-through rate is the signal that separates listings that rank from listings that just exist. It is the ratio of units sold to units listed over a period. A high ratio tells Cassini that buyers want this product at this price, so the engine shows it more, which drives more sales, which lifts the ratio further. It is a flywheel.
Price is the lever you control that most affects sell-through. A competitive price relative to similar listings raises the chance of each sale, which raises velocity, which raises rank. This does not mean racing to the bottom. It means pricing with awareness of what comparable listings charge and where your value sits. Overpricing kills velocity and rank together.
If a listing has stalled, check its price against current comparable sales before you touch anything else. A price that was competitive a season ago may not be today. Small, informed price adjustments often restart velocity faster than any other change.
Listing format also feeds sell-through. A fixed-price listing that stays live builds a longer sales history than a series of short auctions, and that steady history gives Cassini more signal to work with. Offering the features buyers expect, such as free or fast shipping and a fair returns window, lifts conversion on the traffic you already get, which raises velocity without touching price. And running an eBay Store can unlock lower fees and more listing tools that support the whole effort. The point is that sell-through is not one setting. It is the combined result of price, format, shipping terms, and listing quality all pointing the same way.
Promoted Listings Standard vs Advanced
Promoted Listings is eBay’s paid tool to boost visibility. It comes in two forms, and they work differently.
Standard charges you a percentage of the sale, and only when a buyer clicks your promoted listing and then buys. It places your listing in organic-style slots with a “Sponsored” label. It is low effort and low risk, because you pay only on a sale. It suits a passive boost across many listings.
Advanced runs on cost-per-click, where you bid on keywords and pay for each click whether or not it converts. It can win priority and top-of-page slots and gives you keyword-level control and detailed reporting. It suits aggressive scaling on listings you know convert well, where the extra visibility justifies paying per click.
| Factor | Standard | Advanced |
|---|---|---|
| Pricing model | Percentage of sale (on sale) | Cost per click |
| Placement | Organic-style slots | Priority and top slots |
| Control | Lower | Higher (keyword bids) |
| Best for | Passive boost | Aggressive scaling |
| Reporting | Basic | Detailed |
Use promotion to support organic rank, not replace it. Paid placement buys visibility while your item specifics, price, and sell-through do the slower work of building organic position. A listing that promotes well and converts also earns the velocity that lifts its free ranking. (Source: eBay Promoted Listings help pages.)
An eBay SEO optimization checklist
Run this pass on any listing that has gone quiet, and on every new listing before you publish.
- Fill every item specific. Complete all applicable fields, not just the required ones. This is the single biggest lever.
- Write a clear, keyword-led title. Use the full character space, lead with the terms buyers search, and skip the stuffing.
- Check your price against comparable sales. Make sure it is competitive today, not last season.
- Upgrade your photos. Multiple clear angles on a clean background, at eBay’s recommended size.
- Structure the description. Short, scannable, answering buyer questions to remove doubt.
- Protect your seller metrics. Ship on time with tracking, keep defects low, and handle returns cleanly to hold or earn Top Rated Seller status.
- Add Promoted Listings where it pays. Use Standard for a passive boost, Advanced for listings you want to scale, while organic rank builds.
Work this list top to bottom. Item specifics and price usually deliver the fastest lift, so start there.
If you would rather have this done for you across a full store, our eBay account management team runs Cassini optimization, Promoted Listings, and performance day to day. eBay is one of several channels in our marketplace expansion strategy, and the same listing discipline carries over from Amazon account management and selling on Walmart Marketplace. For more on ranking across channels, see our ecommerce insights, or book a free audit.
Frequently asked questions
What is the Cassini algorithm?
Cassini is eBay’s search engine, the system behind the default Best Match sort. It ranks listings by relevance, price, listing quality, seller performance, and sell-through rate.
How do I rank higher on eBay?
Fill every item specific, write a clear keyword-led title, price competitively, keep strong seller metrics and Top Rated Seller status, and use Promoted Listings to build visibility while organic rank grows.
Do item specifics affect eBay ranking?
Yes, strongly. They drive relevance by telling Cassini what your product is, and they control whether your listing appears when buyers use search filters.
What is sell-through rate on eBay?
The ratio of units sold to units listed over a period. A higher rate signals buyer demand to Cassini, which lifts your ranking.
What is the difference between Standard and Advanced Promoted Listings?
Standard charges a percentage of the sale and only when a promoted click converts. Advanced runs on cost-per-click bidding with keyword control and priority placement.
Does Top Rated Seller improve ranking?
Yes. It brings a visibility advantage in search plus fee discounts, both earned by meeting eBay’s shipping, defect, and service standards.
Sources: eBay Seller Center and Best Match documentation (primary); eBay Promoted Listings help pages (primary); eBay-seller ranking-factor research (2026).
Want this done for you?
GrowEventure is a marketplace account-management agency that can manage your eBay store for your brand. Book a free store audit and we’ll point out the quickest wins.
