Understand How Cassini Thinks
eBay's Cassini search engine optimizes for a different goal than Amazon's A9. Where Amazon wants to maximize its own commission on high-converting sales, Cassini wants to maximize the value of every transaction for both buyer and seller — and to keep buyers returning to eBay. This means Cassini weighs seller reputation, shipping speed, and listing quality factors that Amazon largely ignores.
Cassini also personalizes results heavily. Two buyers searching the same query may see different listings based on their location, past purchases, and browsing behavior. This makes single-keyword ranking obsession less productive on eBay than on Amazon; your goal is to be the best match for the widest range of relevant buyer intents, not to win one specific query.
The implication is practical: optimize your whole listing ecosystem — titles, item specifics, images, shipping, returns, and seller metrics — rather than gaming one factor. Cassini rewards sellers who look like a safe, satisfying choice from every angle.
Item Specifics Are Your Secret Weapon
Item specifics are the structured attributes you fill in when creating a listing — brand, color, size, material, MPN, and dozens of category-specific fields. Cassini uses these aggressively for filtering and matching. If a buyer filters for a specific size or color and you haven't filled in that specific, you're invisible to them even if your title is perfect.
Fill in every single recommended item specific, and as many additional ones as apply. eBay shows you which specifics are required, recommended, and optional in the listing tool. Treat recommended and optional as required. Many sellers skip optional fields and lose filtering visibility without realizing it.
Accurate item specifics also improve your chances of appearing in Google Shopping results, which drives external traffic to your eBay listings. This is a double win — better Cassini ranking and free off-platform discovery.
Free and Fast Shipping Signals
Cassini gives a meaningful boost to listings with free shipping. Buyers filter for free shipping constantly, and even when they don't, the algorithm appears to prefer listings that remove shipping-cost friction. If your margins allow, build shipping into your price and offer free shipping — the ranking and conversion lift often outweighs the cost.
Fast handling time matters too. One-business-day handling signals to Cassini that you're a reliable seller, and eBay's Fast 'N Free badge (which combines free shipping with quick delivery estimates) is a conversion booster that indirectly improves ranking through higher click-through and sale rates.
If you can't offer free shipping on everything, offer it on your highest-volume items and at least match competitors' shipping costs on the rest. Shipping competitiveness is a relative factor — you don't need to be the cheapest, just not conspicuously expensive.
Title Structure Beats Keyword Stuffing
eBay titles are capped at 80 characters, far shorter than Amazon's 200. This forces discipline. The most effective structure is: Brand + Model/MPN + Key Descriptor + Size/Color/Variant + Primary Use. Put the most important words first, because Cassini gives slight extra weight to early title words and buyers scan the left side of titles.
Avoid keyword stuffing with irrelevant terms. Cassini penalizes listings that attract clicks but don't convert, and stuffed titles often disappoint buyers who click expecting one thing and find another. A clean, accurate title converts better and ranks better as a result.
Use synonyms strategically in your item specifics rather than cramming them into the title. If buyers search 'sneakers' and 'trainers,' put 'sneakers' in the title and capture 'trainers' through the style or subtype item specific. This keeps your title readable while maximizing query coverage.