eBay Cassini Algorithm 2026: Ranking Guide for Sellers
Cassini is eBay's internal search engine. It ranks every listing based on relevance, seller trust, and listing quality. If your products do not appear on page one for buyer searches, Cassini is the reason, and the fix is in your control.
This guide breaks down what Cassini measures in 2026, where most sellers leak ranking, and the exact actions that move listings up. The three pillars are weighted roughly 40 to 50 percent relevance, 30 to 40 percent seller performance, and 20 to 30 percent listing quality.
What Cassini Actually Measures
Cassini does not see your photos the way buyers do. It sees structured data: your title tokens, item specifics, price, shipping promise, sell-through history, defect rate, and engagement signals. Every action a buyer takes (click, watch, ask a question, buy) feeds back into your future rank.
Three pillars decide where you land:
| Pillar | Weight | What it looks at |
|---|---|---|
| Relevance | 40 to 50% | Title match, item specifics match, category fit |
| Seller performance | 30 to 40% | Defect rate, late shipment rate, cancellations, feedback, return rate |
| Listing quality | 20 to 30% | Photos count and size, free shipping, price competitiveness, conversion rate |
Pillar 1: Title and Item Specifics Decide Relevance
Your title is the single biggest direct ranking lever. Cassini matches buyer queries against the title before it looks at anything else. If the searched word is not in your title, the listing does not enter the candidate pool.
Rules that survive in 2026:
- Use 70 to 80 of the 80 character limit. Empty space is wasted ranking capacity.
- Lead with the brand or model when possible. Cassini gives early tokens slightly more weight.
- Include one variation form (plural, color, size) so you also match modified queries.
- Drop filler words like "NEW," "L@@K," "WOW," and emoji. Per eBay's listing policy these flag manipulation and can demote the listing.
Item specifics matter just as much for the structured side of search. Buyers filter results by brand, color, material, size. If a specific is missing, your listing is excluded from that filter, no matter how good the title is. Fill every required and recommended field.
To move faster, our title builder tool generates 80-character titles using top-converting eBay tokens, and the title builder feature inside the dashboard repeats the same logic across an entire catalog.
Pillar 2: Seller Performance Is a Multiplier
A perfect title cannot save a Below Standard account. Cassini multiplies your relevance score by your seller health, so a single bad metric can quietly cut your visibility in half.
The four numbers eBay tracks per seller:
| Metric | Threshold (Top Rated) | What hurts it |
|---|---|---|
| Defect rate | Below 0.5% | Item not as described, INR claims |
| Late shipment rate | Below 3% | Missing handling-time window |
| Cases closed without resolution | Below 0.3% | eBay siding with buyer |
| Tracking uploaded on time | Above 95% | Missing tracking number on shipped orders |
Dropshippers fail Cassini most often on late shipment rate. The supplier ships in three days, you set a one-day handling time on eBay, and the gap shows up as a defect. Either match your handling time to the supplier's real cutoff, or use an automation layer that pulls live tracking the moment the supplier dispatches. Our order sync guide walks through that setup.
Pillar 3: Listing Quality Closes the Loop
Listing quality is where Cassini watches buyer behavior. Click-through rate and conversion rate are the two signals that compound. A listing that converts at 4 percent will outrank a listing in the same niche that converts at 1 percent, even if everything else looks identical.
What moves the quality score:
- Eight or more photos at 1600 pixels on the longest side. Listings with eight plus images convert about 30 percent better than those with three.
- Free shipping flag. Cassini factors total cost (price plus shipping) into rank, and free-shipping listings get a small dedicated boost on top.
- Price competitiveness inside the same category. Cassini reads the median sold-comp price and rewards listings priced within 10 percent of it.
- Mobile-fast page load. Heavy HTML descriptions, custom fonts, and embedded videos hurt mobile load times and Cassini measures this since 2024.
The Risks of Gaming Cassini
Three common shortcuts get accounts demoted or restricted in 2026:
- Keyword stuffing the title. eBay's search and browse manipulation policy bans this. Sellers caught lose visibility on the affected listings and sometimes the whole store.
- Duplicate listings. Posting the same item across ten near-identical listings to fight for shelf space dilutes your sales history. Cassini treats duplicates as low-quality and can suppress all copies. We covered the cleanup in how to avoid duplicate listings on eBay.
- Buying clicks or watchers. Click-farm services exist, but eBay's bot detection has improved every year. Detected fake engagement leads to selling restrictions.
How to Rank on Cassini Safely
The winning formula in 2026 is boring: write strong titles, fill every item specific, hold seller metrics in green, ship inside the promised handling window, and monitor pricing daily so you stay competitive without selling at a loss.
A few mechanical wins that stack quickly:
- Use the eBay fee calculator tool before each listing to confirm your margin survives Cassini's price-competitiveness range.
- Turn on the price and stock monitor so prices stay near supplier cost without manual edits.
- Use the bulk lister to roll out fully-specified listings instead of fixing them one by one.
Behavior Signals: The Hidden Half of Cassini
Relevance and seller metrics get most of the airtime, but Cassini's quiet workhorse is buyer behavior. Every search session feeds a feedback loop: impressions, clicks, watches, asks, and sales all weigh against the listings that earned them.
Four behavior signals to engineer for:
- Click-through rate. Higher is always better. The first photo and the first 35 characters of the title decide whether a buyer clicks. Test variations on slow listings and keep the version that wins.
- Watch count. Watchers are not the same as buyers, but Cassini reads sustained watching as buyer interest and gives those listings extra impressions. Best Offer enabled listings tend to attract more watchers.
- Conversion rate. A listing seen 200 times that converts to one sale ranks worse than a listing seen 50 times that converts to one sale. Tighter targeting beats spray-and-pray traffic.
- Question rate. When buyers ask a lot of questions, Cassini reads it as confusion in the listing. Add the answers to your description and your conversion rate climbs without changing the price.
How New Listings Get Their First Boost
Every new listing receives a temporary visibility window of seven to ten days. Cassini surfaces it to a small slice of the audience, watches the engagement, and then either sustains the position or drops it.
What happens during that window decides where you settle long-term. Sellers who score at least one sale in the first week typically see the listing hold a stable rank afterwards. Sellers who get clicks but no sales settle into a low position that is hard to escape without relisting.
Two tactics that maximize the new-listing boost:
- List during the buyer-active window. US prime time is roughly 6 to 10 PM Eastern. Cassini gives the new listing its earliest impressions while buyers are most active.
- Pre-build promoted listings at a low ad rate. Two to three percent ad rate during the boost window funnels paid impressions into the same engagement loop, which Cassini treats as organic-relevant data.
Quick Cassini Audit Checklist
Run this on any listing that is not ranking:
- Title uses 70 plus characters, no filler words, primary keyword first.
- Every required and recommended item specific is filled.
- Eight or more photos, 1600 pixels minimum on the long side, white background on photo one.
- Free shipping flagged, or shipping cost under 10 percent of the price.
- Handling time matches your supplier's real cutoff.
- Listing has at least one sale within the first week of going live.
- Defect rate below 0.5%, late shipment rate below 3% on the seller dashboard.
- Price within 10 percent of the median sold-comp price for the same model.
- Description answers the top three questions buyers usually ask.
- Best Offer enabled with a sensible auto-decline floor (typically 70 to 75 percent of list price).
Work the checklist top to bottom, fix one row per session, and Cassini will start moving you up.
Ready to apply this to a real catalog? Start a free SuperDS trial and run the title builder, item specifics audit, and price monitor on every listing in your store from the first day.