eBay SEO in 2026: how Cassini ranks listings, a Cassini vs Google factor table, Item Specifics by category.
Written by
Nella Cheng
Published on
June 13, 2026
Key takeaways
Last updated 14 June 2026. Published by Sizely (size.ly); Sizely makes the size chart tool recommended near the end of this article.
eBay SEO involves optimizing your listings and store so eBay's search engine, Cassini, places them higher when buyers look. Cassini isn't Google. It favors listings that sell, not just those packed with keywords. Quick wins are best: put your top keywords in the first 80 characters of the title, complete every Item Specific eBay provides, add product identifiers (UPC, EAN, ISBN, or MPN), set competitive pricing, keep your service metrics strong, and craft a description that genuinely helps the buyer make a decision. Do this, and your items will rank higher in search and convert more of the traffic they attract.
Here’s how Cassini operates, what it considers, and the exact fields to fill out so your listings rank and sell in 2026.
Google ranks pages on relevance and authority, while Cassini ranks based on relevance and the chance a buyer will click and purchase. That second part is key. eBay's ranking system, Best Match, is powered by Cassini. It considers your listing's recent sales, click-through rate, conversion rate, price, shipping cost and speed, return policy, and seller performance. A keyword-perfect listing with no sales will lose to a simpler one that converts well.
The table below shows what each engine rewards. The eBay column is based on eBay's own seller guidance for Best Match results (eBay Seller Center, "How Best Match works"); the Google column reflects Google's relevance-and-authority model as documented in its public Search guidance.
| Ranking Factor | Ebay (Cassini / Best Match) | Google Search |
|---|---|---|
| Keyword relevance in title | High | High |
| Conversion rate (buys per view) | High | Not a direct factor |
| Recent sales velocity | High | Not applicable |
| Structured fields (Item Specifics) | High | Schema markup, lower weight |
| Price and shipping cost | High | Not a ranking factor |
| Return policy and seller metrics | Medium to high | Not applicable |
| Backlinks and domain authority | Not a factor | High |
| Page load speed | Low | Medium |
The practical takeaway: keywords help you get into search results, but buyer behavior determines your position. Write for both the search query and the buyer.
You have 80 characters for a listing title, as per eBay's guidelines. Cassini analyzes every word, so use terms a buyer would actually search for. A solid sequence is brand, product type, and then details that refine a search: size, color, material, model number, and condition.
Consider these examples:
The strong title lists the brand, the item, the size, the color, two attributes, and a style term buyers search for. Avoid filler like "wow", "rare", or "L@@K". Skip ALL CAPS and strings of special characters. Never include a brand name if the item isn't that brand. eBay's keyword spam policy clearly bans adding unrelated brand names or keywords, and doing so can result in removal of the listing.
eBay offers an optional subtitle for a small fee. It doesn't contribute to Cassini's keyword index like the title does, so avoid filling it with keywords. Use it to highlight something the title couldn't, like "Free 2-day shipping" or "New with tags, never worn." If it doesn’t provide a genuine reason to click, skip it and save the fee.
Item Specifics are structured fields shown under the title (Brand, Size, Color, Type, Style, Material, Department, and more depending on the category). These are some of the most valuable SEO spaces on the platform because eBay's search filters rely on them. When a buyer checks "Size: M" and "Color: Green" in the sidebar, only listings that filled those fields will appear. Leave them blank, and you disappear from filtered searches.
Which fields matter most depends on what you sell. The table below highlights the Item Specifics that carry the most filter traffic in three common categories, so you know where to focus your efforts first.
| Category | Required Fields Buyers Filter By | High-Value Optional Fields |
|---|---|---|
| Women's clothing | Brand, Size, Color, Department, Type | Style, Material, Sleeve length, Occasion, Pattern |
| Sneakers and shoes | Brand, US shoe size, Color, Department | Model, Upper material, Style code, Width |
| Electronics (phones) | Brand, Model, Storage capacity, Color | Network, Carrier, Condition, Connectivity |
eBay designates some Item Specifics as recommended and others as required. Fill them all, whether required or not. If a field has a dropdown, select the eBay-provided value instead of typing your own, so your listing aligns with the exact filter buyers use.
SEO for eBay isn’t just about words. Product identifiers link your listing to eBay's catalog and outside shopping engines. A UPC or EAN barcode, an ISBN for books, or a manufacturer part number (MPN) connects your item to a known product, which can draw in a stock photo, a product page, and reviews. It also makes your listing eligible to appear in Google Shopping and other comparison feeds eBay syndicates to.
If the item is handmade, vintage, or truly lacks an identifier, mark the field as "Does not apply" instead of leaving it empty. eBay advises sellers to use the correct value or "Does not apply," not a placeholder. Falsifying a UPC is worse than honestly stating "Does not apply."
eBay recommends at least 200 words in the description, with the most important keywords closer to the start and end. Begin with what the item is and who it’s for. Then, detail the specifics a buyer needs before committing: exact measurements, condition with any flaws listed candidly, materials, fit notes, and what's included.
Two aspects matter more than keyword density here. First, accuracy. Cassini monitors your return rate and "item not as described" cases, and both can lower your ranking. A description that overpromises leads to returns, which quietly push you down the ranks. Second, completeness. Answering every likely question a buyer could have removes reasons to switch to a competitor.
Repeating a keyword excessively doesn't boost your rank, and listing unrelated brand names to hijack their searches breaks eBay's keyword spam rules. eBay's "Avoiding search manipulation" policy cites both repeated keywords and irrelevant brand mentions as reasons a listing might be demoted or removed. Write naturally. Cassini measures if people buy, and overly stuffed listings read like spam and convert poorly.
The majority of clothing returns are due to incorrect fit. The buyer guesses the size, it doesn’t fit, it gets returned, and your seller metrics take a hit that Cassini notes. A straightforward size chart with garment measurements (chest, waist, length in inches and centimeters) helps buyers pick the correct size before purchasing. This reduces wrong-size orders, leading to fewer returns and a higher Best Match score over time.
Sizely offers a web tool that lets online sellers craft a size chart from over 300 garment templates and embed it directly in an eBay listing. It is trusted by 85,000+ sellers to cut returns and boost sales. If fit-related returns are impacting your profits, this is where to start: size.ly. It is used by more than 85,000 sellers.10835
Over half of eBay's buyers shop via mobile, primarily through the eBay app. Cassini doesn’t rank mobile and desktop separately, but a listing that doesn’t read well on a small screen converts less effectively, and conversion is what Cassini rewards. Keep titles front-loaded so important terms appear before the truncation. Break descriptions into short paragraphs and bullet points instead of one large block of text. Ensure your photos are clear thumbnails, as this is the first thing mobile buyers see in results.
Cassini is eBay's search engine, the force behind Best Match results. It ranks listings based on relevance to the search and the likelihood a buyer will click and purchase, taking into account sales history, conversion rate, price, shipping, return policy, and your seller performance.
Use the full 80 characters with genuine search terms, not a fixed count of keywords. Arrange them as brand, product type, then narrowing details like size, color, and material. Avoid word repetition and filler like "L@@K" or "rare."
Yes. eBay's search filters are built from Item Specifics, so a listing with blank fields vanishes when a buyer filters by size, color, or brand. Filling them out is one of the highest-impact SEO strategies on the platform.
Indirectly, but significantly. Cassini accounts for conversion and seller performance, and a clear, generous return policy boosts conversion while a high return rate harms your metrics. Reducing wrong-size returns with accurate descriptions and a size chart enhances both.
New and updated listings can shift within days because Cassini reacts to recent click and sales data. Sustained ranking improvements develop over weeks as your listings gather views, sales, and maintain clean service metrics.
Written by
Nella's strategic approach to content creation, combined with her extensive experience as an online seller, provides Sizely's audience with actionable insights into the world of sizing and fit. Her expertly crafted content helps demystify complex sizing challenges for both businesses and consumers.
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