eBay Cassini Algorithm Explained: How to Rank Your Listings Higher

Two sellers can list an almost identical product, at a similar price, with similar photos — and one will sit on page one of eBay search results while the other languishes on page eight. The difference almost always comes down to how well each listing is optimised for Cassini, eBay's search ranking algorithm. This guide explains exactly how Cassini works and what you can change today to start ranking higher.

What Is Cassini?

Cassini is the name of eBay's search engine, the system that decides which listings appear, in what order, when a buyer searches for a product. It replaced eBay's older "Best Match" algorithm and was specifically designed to reward listing quality and buyer experience over simple keyword stuffing — meaning many of the tactics that worked under the old system actively hurt rankings under Cassini.

Cassini evaluates two broad categories of signal: relevance (does this listing actually match what the buyer searched for) and performance (is this a listing buyers historically engage with and complete purchases from).

The Core Ranking Factors

Listing Title Relevance

Your title needs to contain the exact words buyers search for, in a natural order, without keyword stuffing. Cassini's relevance matching has become sophisticated enough to understand intent beyond exact keyword matches, but title clarity still matters enormously — a confusing or padded title performs worse than a clean, accurate one.

Item Specifics Completeness

This is one of the most underused ranking levers available to sellers. Every item specific you fill in (brand, size, colour, material, compatibility) gives Cassini more structured data to match your listing against filtered searches. A listing with all relevant item specifics completed will consistently outrank an otherwise identical listing that left half of them blank, because incomplete listings get filtered out of refined searches entirely.

Seller Performance Metrics

Your seller-level metrics — defect rate, late shipment rate, case resolution — feed into a trust score that affects every listing in your store, not just the problematic one. A handful of late shipments can quietly suppress the ranking of your entire catalogue, which is why operational reliability is as much an SEO factor on eBay as anything in the listing itself.

Listing Engagement Velocity

Cassini watches how buyers interact with your listing relative to how often it's shown: click-through rate, watch count, and conversion rate from view to purchase. A listing that gets clicked and bought at a higher rate than competitors for the same search term gets pushed upward, creating a compounding advantage — visibility drives engagement, which drives more visibility.

Price Competitiveness

Price alone doesn't determine ranking, but price relative to comparable listings for the same item does influence Cassini's relevance scoring, particularly for commodity products where buyers are highly price-sensitive. This doesn't mean racing to the bottom — it means understanding where your price sits relative to the realistic competitive set for that exact item.

Listing Format and Free Shipping

eBay has stated publicly that listings offering free shipping receive a ranking boost, since free shipping correlates strongly with buyer satisfaction and completed purchase rate. Where margins allow, building shipping cost into the item price rather than charging separately for it is usually worth the ranking benefit.

A Practical Cassini Optimisation Checklist

• Complete every available item specific field, even ones that seem optional
• Write titles using the exact terms buyers search for, front-loading the most important keywords
• Use all available photo slots with genuinely high-quality, well-lit images from multiple angles
• Offer free shipping where your margin allows it
• Respond to buyer messages within a few hours, not days — response time affects your seller metrics
• Price competitively against directly comparable listings, not against unrelated products in the same category
• Maintain a defect rate below eBay's "Top Rated" threshold to unlock the associated ranking and trust badge benefits

Common Mistakes That Hurt Cassini Rankings

The most damaging mistake is leaving item specifics incomplete to save time during bulk listing — this single shortcut quietly excludes your listings from filtered search results, which on many categories account for the majority of buyer searches.

The second is keyword stuffing titles with irrelevant terms in an attempt to capture more searches. Cassini's relevance algorithm penalises titles that don't match buyer intent cleanly, so a stuffed title often performs worse than a clean, accurate one.

The third is ignoring seller performance metrics until they become a problem. Because these metrics affect your entire store's ranking, not just individual listings, a slow drift in late shipment rate can suppress sales across your whole catalogue without an obvious single cause — regular monitoring of your Seller Dashboard catches this before it compounds.

How Long Does Cassini Re-Ranking Take?

Changes to a listing (improved title, completed item specifics) typically begin influencing ranking within a few days, since Cassini re-indexes listings relatively frequently. Seller-level metric improvements (reducing defect rate, improving shipping speed) take longer to reflect in rankings, since these are calculated over rolling 30-90 day windows.

Photo Quality as a Ranking and Conversion Factor

While photo quality isn't an explicitly confirmed direct Cassini ranking input in the same way item specifics are, its effect on click-through rate and conversion rate means it influences ranking indirectly through the engagement signals Cassini does measure. A listing with genuinely sharp, well-lit, multi-angle photography consistently earns a higher click-through rate from search results than a listing with a single blurry stock photo — and that higher click-through rate, sustained over time, is exactly the kind of engagement signal that pushes a listing upward in Cassini's ranking.

Practical photography improvements that compound this effect: shoot against a clean, consistent background, use all available photo slots rather than just the minimum required, include a photo showing scale or the product in genuine use, and avoid heavy watermarking or promotional text overlaid on the image itself, which eBay's policies restrict and which buyers tend to find less trustworthy regardless of policy.

International Selling and Cassini

For UK sellers shipping internationally, Cassini's relevance matching also factors in the buyer's location relative to your stated shipping options and estimated delivery times. A listing offering clear, accurate international shipping with realistic delivery estimates tends to rank better for international buyer searches than one offering only domestic shipping or vague international shipping terms that create buyer uncertainty during the search and decision process.

If international sales are a meaningful part of your strategy, setting up eBay's Global Shipping Program or clearly defined international shipping rates — rather than leaving international buyers to message you asking whether you ship to their country — both improves buyer experience and removes friction that would otherwise suppress your engagement metrics.

Top Rated Seller Status and Its Ranking Benefit

eBay's Top Rated Seller badge isn't just a trust signal for buyers — it's tied to a confirmed ranking benefit within Cassini for sellers who maintain it. Qualifying requires meeting specific thresholds across defect rate, late shipment rate, and tracking upload consistency over a rolling evaluation period, and losing the status (even temporarily, due to a run of late shipments during a busy period) can produce a noticeable, if usually temporary, dip in listing visibility until the metrics recover.

For UK sellers, this makes operational consistency during high-volume periods (Christmas, January sales) particularly important, since exactly the periods where sales volume is highest are also the periods where shipping delays are most likely to occur — and most likely to damage the metrics underpinning Top Rated status if fulfilment processes aren't built to handle the increased load reliably.

Multi-Channel Sellers and Cross-Platform Considerations

Many UK sellers run eBay alongside Amazon, Etsy, or their own Shopify store, and a common question is whether listing identical products across multiple platforms hurts eBay-specific performance. It doesn't directly — Cassini evaluates your listing on its own merits within eBay's ecosystem, regardless of where else that product is also listed. What matters for multi-channel sellers is keeping inventory and pricing synchronised across platforms to avoid overselling, and ensuring eBay-specific listing optimisation (the item specifics and title structure covered above) isn't neglected simply because the same product description was copied wholesale from another platform's listing.

Frequently Asked Questions

Does running eBay Promoted Listings affect organic Cassini ranking?

No — Promoted Listings is a separate paid placement system that sits alongside organic Cassini results. It doesn't directly boost your organic ranking, though the additional visibility and resulting sales can indirectly improve your engagement metrics over time.

How important are reviews and feedback for Cassini ranking?

Seller feedback score and percentage feed into the overall trust signals Cassini considers, though item-specific factors (title relevance, item specifics, engagement) tend to have a more immediate and direct impact on a given listing's individual ranking.

Can a brand-new eBay store rank well immediately?

New stores start with limited performance history, so initial rankings rely more heavily on listing-level relevance factors (title, item specifics, photos) since there isn't yet engagement data to draw on. Building a track record of fast shipping and low defect rates over the first few months is what unlocks stronger rankings afterward.

Key Takeaways

Cassini rewards complete, accurate, well-performing listings over keyword-stuffed or incomplete ones — the algorithm has matured well past the tactics that worked years ago. The highest-leverage changes available to most sellers today are completing every item specific field, writing clean accurate titles, and protecting seller performance metrics through reliable shipping and responsive customer service.,