eBay Cassini Search Engine Explained (2026): Ranking Decoded

Quick answer: Cassini is eBay's search engine, the system that sorts listings into Best Match, the default order buyers see when they search. eBay says Best Match weighs seven things: how closely a listing matches the search terms, how popular the item is, its price, the quality and completeness of the listing, the listing terms such as returns and handling time, and your track record as a seller. There is no secret trick. Complete, accurate listings at competitive prices from sellers who ship on time rank higher. For dropshippers who want those habits built into every listing, our pick is Ecomli, a non-API browser extension for eBay dropshippers. Ecomli makes that tool, so weigh our pick with that in mind.

• Relevance comes first. A clear title of up to 80 characters, the right category and full item specifics decide which searches and filters a listing can appear in.
• Popularity and price come next. Items that sell, at prices in line with the rest of the results page, get shown more.
• Your seller record counts. Late shipments, missing tracking and cancelled orders work against you. Top Rated Plus listings get a seal in search results.
• Policy breaches remove you from search. Duplicate fixed-price listings and restricted items don't rank lower. They don't show at all.

This guide explains what the eBay search engine Cassini is, what eBay itself says about Best Match, how each factor works in practice, what works against you, and a listing workflow that lines up with all of it. Where eBay hasn't published how something works, we say so rather than guess.

What Cassini actually is

Cassini is the name eBay uses internally for the search engine behind its results. According to a June 2013 report in Wired, eBay rolled Cassini out to US users that month to replace its old search engine, Voyager. The project was led by Hugh Williams, then eBay's vice president of experience and search. Wired described the goal plainly: at eBay, success means something bought and something sold, and Cassini was built to learn which data predicts that.

Cassini powers Best Match, the sort order buyers get unless they choose another. It works on a closed catalog. eBay Inc. puts its live listings at about 2.6 billion on its company page, and every one of them is built from the same parts: title, category, item specifics, photos, description, price, shipping and returns. That structure is the reason eBay search behaves differently from web search. Cassini can compare listings on hard, structured facts as well as on the words in a title.

eBay doesn't use the name Cassini in its seller help. It talks about Best Match. The two describe the same thing from different sides: Cassini is the engine, and Best Match is the order it produces.

What eBay says Best Match weighs

eBay's help page on optimizing listings for Best Match lists the factors its algorithm considers:

• How closely the listing matches the buyer's search terms
• How popular the item is
• The price of the item
• The quality of your listing, such as the description and photos
• How complete the listing is
• The listing terms, such as your return policy and handling time
• Your track record as a seller

The same page says there is no secret to improving your position, and that sellers who follow good listing and selling practices see their items appear higher. eBay doesn't publish weights for these factors. Anyone who tells you a factor is worth an exact percentage, or that a specific click-through rate guarantees a position, is guessing. The sections below group the factors into four areas you can act on.

Relevance: title, category and item specifics

Relevance decides whether your listing is a candidate for a search at all. eBay's guidance covers three parts.

The title

eBay asks for a clear, concise title with correct spelling and no more than 80 characters. Lead with the words buyers actually type: brand, model, the key spec, then size, color or variant. Filler such as "wow" or "L@@K" takes up space without matching any search, and eBay's own guide to finding a listing warns that misspellings, words run together and special characters such as ! and @ can keep a listing from showing. Our eBay listing title best practices and our guide to keywords for eBay listings cover how to research and order the words.

Item specifics

eBay asks sellers to add item specifics such as make, model, size, color and style, because the more it knows about an item, the better it can match it to buyer searches. Item specifics also power the filters buyers click to narrow results. A listing without a color value can't match a buyer who filters by color. On most listings this is the quickest improvement available, and our eBay item specifics guide goes field by field.

Category and catalog

List in the category that is most relevant to the item. eBay also suggests using product details from the eBay catalog in your description where you can, which gives search more structured facts to match.

Popularity and price

eBay lists how popular the item is and its price as separate factors. It doesn't publish exactly how it measures popularity, but sales are the clearest signal a marketplace has, and the Wired report describes success at eBay as something bought and sold. That has two practical effects.

Product choice matters more than polish. A well-written listing for something few people want won't hold a high position. Check demand before you list. Search sold listings, or use Product research in Seller Hub, which shows average sold price and sell-through rate. Our guides to what Terapeak is, the eBay product research method and eBay sell-through rate walk through the checks.

Price is judged in context. eBay's advice starts with competitive prices, reasonable shipping and good customer service. A listing priced far above the others on the same results page gives buyers a reason to skip it. Being the cheapest isn't required, and it isn't a strategy you can sustain once fees and supplier costs are counted. Our guide to repricing with a margin floor covers how to stay competitive without selling at a loss.

Listing quality and completeness

eBay treats the quality and the completeness of a listing as two factors. In practice they come down to photos, the description and whether every field is filled.

• Photos. Use high-quality photos taken from every angle and show any flaws or scratches. eBay lets you include up to 24 pictures for free. Don't add borders or text to your photos, and don't use the catalog stock photo as your main picture if your item isn't brand new. Our guide to eBay photo resolution and image size covers the specs.
• Description. Describe the item clearly and accurately, including condition, what's in the box, sizing and materials. Many buyers read on a phone, so keep the layout simple and easy to read on a small screen.
• Selling terms. State shipping and handling costs, accepted payment methods and your return policy, and spell out any international limits.
• Format. eBay suggests fixed price when you know the value, have multiple items or want the listing to stay up for more than 10 days, and auction-style when you're unsure of the value or the item is unique. Our comparison of eBay auction vs Buy It Now goes deeper, and eBay variation listings covers grouping sizes and colors in one listing.

Listing terms and your track record as a seller

The last two factors are about what happens after the sale. eBay names return policy and handling time as listing terms it considers, and it asks sellers to keep a positive selling history: ship on time, use tracking where possible, describe items accurately and keep track of inventory so you don't have to cancel sales.

eBay's seller performance policy turns that history into a seller level, evaluated on the 20th of each month. These are the thresholds for Top Rated:

Every seller must stay within the minimums: no more than 2 cases closed without seller resolution (or 0.3%) and a transaction defect rate of no more than 2%. Below Standard sellers can face selling limits and higher final value fees. Top Rated sellers who offer same or 1-business-day handling and free returns of 30 days or longer can qualify listings for Top Rated Plus, which shows a seal prominently in search results and gives a 10% discount on final value fees. Our guide to eBay seller performance metrics explains each metric.

For dropshippers, handling time is the hard part. Set it to what your supplier can actually deliver. Promising faster handling than you can meet turns into late shipments, and late shipments count against the track record Best Match weighs. Our supplier vetting framework covers what to test before you list a supplier's products.

What works against you in eBay search

Some problems lower a listing's position. Others take it out of search entirely. eBay's help pages name these:

• Duplicate listings. Under the duplicate listings policy, eBay doesn't allow more than one fixed-price listing of an identical item at the same time from the same seller, including the same item in different categories or under different usernames. Posting copies to "cover more searches" works against you.
• Title errors. Misspellings, words run together and special characters can keep a listing from showing for the searches it should match.
• Policy problems. A listing for a prohibited item, or one that infringes intellectual property, can be removed.
• Cancellations. Selling something you can't supply forces a cancellation, and eBay asks sellers to track inventory to avoid exactly that.
• Late shipments and missing tracking. Both feed your seller level, which feeds the track record factor.

eBay also says a new listing should show up in search within 24 hours. If it doesn't, check that it is active rather than a draft, that the title has no errors, and that it isn't a duplicate, as eBay's page on finding your listing suggests.

A listing workflow that lines up with Best Match

Knowing the factors is half the job. The other half is a routine that feeds them on every listing:

1. Research before you list. Pick products with a sales history. A product few people buy can't be written into a high position.
2. Build the listing completely. A title in brand, model, spec, variant order. Every recommended item specific filled. Several clear photos with a clean main image and no borders or text. An accurate description and clear terms.
3. Set honest terms. Handling time your supplier can meet, a return policy you can honor, and tracking on every order.
4. Watch the first week. Check views and sales in Seller Hub. Plenty of views and no sales usually points to price or trust. Few views points to the title, category or item specifics. Change one thing at a time.
5. Keep prices and stock in line. When supplier costs or stock change, update the listing before a buyer finds the problem for you.
6. Protect your seller level. Review late shipments, tracking and cancellations every week, and fix the cause rather than the symptom.

How to do this in Ecomli

Ecomli is a non-API browser extension for eBay dropshippers. It works through the eBay seller account already signed in to your desktop Chrome browser, so there is no API connection to authorize, and it lists products from Amazon and AliExpress. No tool can promise a search position, but several parts of Ecomli map straight onto the Best Match factors:

• Popularity: Product Hunting. Product Hunting researches an eBay seller's sold history or current listings and matches the products to Amazon or AliExpress, so you start from items with sales behind them. A match is a lead to check, not proof of profit.
• Relevance and quality: Create Listings. Create Listings reads the supplier product, prices it with your markup, writes optional AI titles and AI descriptions from supplier facts, applies your description template and fills eBay's listing form in your seller session, with duplicate checks before publishing. Review each AI title against the brand, model, spec pattern, and check the recommended item specifics on your best sellers by hand.
• Photos and descriptions: Templates. Ecomli's templates include 30+ mobile-friendly description designs on every plan. On Pro and Scale, image templates apply eBay-compliant layouts to the first gallery photo. Decorative badge and text presets are download-only, because eBay doesn't allow text or borders on listing photos.
• Policy risk: Safety Shield. Safety Shield screens products, AI copy and the eBay draft for flagged brands and restricted items before publishing. It is a checkpoint, not a guarantee.
• Price and inventory: Stock Monitoring. Stock Monitoring checks supplier stock and prices for your Ecomli listings and updates the eBay price and quantity, or ends out-of-stock items, using your rules. That is the inventory tracking eBay asks for to avoid cancellations. Positioning against competitor prices stays your call.
• Track record: Auto Ordering and Tracking Conversions. Starter orders manually. On Pro, you click Auto Order and Basic Auto Ordering places the supplier order in your own browser. On Scale, once you turn it on, Advanced Auto Ordering runs on Ecomli's servers and places the supplier order for new eBay orders without a click, as long as each order is within your buying limits (a maximum purchase price and a maximum loss). Tracking Conversions converts supported AliExpress tracking and Amazon TBA tracking numbers into eBay-compatible tracking and adds it to the eBay order after automatic checks.
• Dead listings: Auto Pruner. On Pro, Auto Pruner ends listings with zero views or zero sales over the period you choose, in one click, using fresh Seller Hub reports. Listings with recent sales or an unknown age stay protected. On Scale, Advanced Auto Pruner can relist removed products with fresh supplier data and a new AI title and description. Relisted items get new eBay item IDs.

Most of these tasks run in your desktop browser while it is open. You can compare which plan includes Auto Pruner and image templates before you choose.

Common Cassini misconceptions

"There's a hidden trick." eBay says there is no secret to Best Match. Complete, accurate listings, competitive prices, reasonable shipping and good service are the whole method.

"The lowest price wins." Price is one of seven factors. A cheap listing with a thin title, missing item specifics and slow handling still loses to a complete one priced in line with the page.

"More listings of the same item means more exposure." Identical fixed-price listings from one seller break the duplicate listings policy. Grow with more products, or group sizes and colors into one variation listing.

"Keywords in the description do the heavy lifting." eBay asks for an accurate description, and it helps buyers decide. The title, category and item specifics are what eBay's guidance puts first for matching searches, so spend your effort there.

"Promoted Listings replace good listings." An ad can put a listing in front of more buyers, but it doesn't fix a weak title, bad photos or slow shipping. Our Promoted Listings guide covers how to run campaigns that pay for themselves.

Frequently asked questions

What is Cassini on eBay?

Cassini is eBay's search engine, the system that ranks listings into Best Match, the default sort buyers see. eBay rolled it out to US users in June 2013 to replace its older engine, Voyager, according to Wired. eBay's seller help calls the result Best Match rather than Cassini.

How long does a new listing take to show up in eBay search?

eBay says a new listing should show up in searches within 24 hours. If it doesn't, check that it is active rather than a draft, that the title has no misspellings or special characters, and that it isn't a duplicate of another active listing.

Does revising a listing reset its ranking?

eBay doesn't publish how revisions affect position. Revisions that make a listing more accurate and complete, such as a clearer title or missing item specifics, line up with what Best Match rewards. Ending a listing and creating a new one is different: the new listing starts without the sales history the old one had, so don't end a selling listing just to start fresh.

Why can't buyers find my listing in search?

Start with eBay's own checklist: the listing may still be a draft, the title may contain misspellings or special characters, it may duplicate another of your active listings, or it may have been removed for a policy problem. Then check that it has full item specifics, because buyers who filter results won't see a listing missing the field they filtered on.

Do Promoted Listings hurt my organic ranking?

eBay doesn't say that promoting a listing lowers its organic position. Promoted Listings are ads: with a general campaign you pay an ad rate when the promoted item sells after a click, and with a priority campaign you pay per click. Sales from ads still add to the item's sales, and popularity is one of the Best Match factors.

How important is the description?

eBay lists listing quality, including the description, as a Best Match factor, and an accurate description reduces "not as described" returns that hurt your record. Keep it clear, mobile-friendly and honest about condition. The title and item specifics still do most of the work of matching searches.

Does Top Rated Plus help in search?

Top Rated Plus listings show a seal prominently in search results, which can help a listing stand out, and they get a 10% discount on final value fees. To qualify, you need Top Rated status plus same or 1-business-day handling and free returns of 30 days or longer.

What is the fastest change I can make to improve my eBay search ranking?

Fill every recommended item specific on your best-selling listings and fix any title errors. It needs no new tools, and it lets those listings appear in the filtered searches they were missing from.

Sources

• eBay: Optimizing your listings for Best Match
• eBay: Finding your listing
• eBay: Seller performance policy
• eBay: Duplicate listings policy
• eBay: Promoted Listings overview
• eBay Inc.: Company overview
• Wired (Marcus Wohlsen, 25 June 2013): In Search of Tech Cred, eBay Builds a New Engine for a New Identity

Find a product, let Ecomli draft the AI title and description, and publish it to eBay from your own browser — no API connection needed. Create your Ecomli account → Plans from $29/month · 7-day money-back guarantee.