eBay AI Listing Generator: 80 Character Titles and Item Specifics for Cassini SEO

eBay search runs on Cassini, an algorithm that ranks listings primarily on title keywords and item specifics. Description text barely affects ranking. This means two thirds of what most sellers spend time on (long descriptions) does almost nothing for visibility, while two fields most sellers under fill (title and item specifics) determine 90 percent of the search outcome. Title analysis of nearly a million eBay listings showed titles using 75 or more of the 80 available characters perform measurably better than shorter ones. This guide covers how Cassini actually works, what ranking listings look like, item specifics in detail, and the workflow that drops listing time from 12 minutes to under a minute.

How eBay’s Cassini search algorithm works

Cassini is the search engine eBay built to rank listings since 2013. It runs differently from every other secondhand marketplace algorithm.

Title keywords carry the most weight

When buyers type into eBay’s search bar, Cassini matches keywords against the title first. The title is the primary ranking signal. eBay allows 80 characters and Cassini parses every word that’s not a duplicate. Titles using 75 or more characters perform measurably better than shorter titles because more keywords means more buyer searches matched.

Item specifics drive filtered search

The second ranking signal is item specifics: structured fields like brand, MPN, model, color, size, condition, material, year. When buyers apply filters in search results, Cassini only returns listings with matching values in those item specific fields. A listing with empty item specifics is invisible to filtered search, no matter how good the title is.

Description barely affects ranking

The counterintuitive fact: Cassini does not parse description text for primary search ranking. Descriptions affect conversion (the click to buy decision after a buyer lands on the listing) but not search visibility. Sellers who spend 10 minutes writing detailed descriptions and skip item specifics are working backwards.

Conversion and engagement compound

Beyond title and item specifics, Cassini tracks listing performance signals: click through rate from search results, conversion rate from views, return rates, dispute rates, seller feedback score. Listings that convert well rise in rankings. Listings with high return rates fall.

The eBay listing format and constraints

Title: 80 characters, use 75+

eBay caps titles at 80 characters. Title research analyzing nearly a million eBay listings found 75+ character titles outperform shorter titles. Use the full space with unique keywords covering brand, MPN, model, color, size, condition, and key features. No keyword repetition (Cassini does not benefit from repeats).

Item specifics: 65 character values, 40 character custom names

Each item specific value caps at 65 characters. Custom item specific names cap at 40 characters. Standard item specifics (brand, MPN, color, size) have predefined eBay options to choose from. Custom item specifics let you add fields not in the default list.

Description: minimal SEO impact

Use descriptions for buyer conversion: condition disclosure, what’s included, return policy notes, reasons to buy. Description text doesn’t carry ranking weight in Cassini, so don’t pack it with keywords hoping for SEO benefit. That time is better spent on item specifics.

Photos: up to 24 free

eBay allows up to 24 photos free per listing on most categories. Use 8 to 12 covering: front, back, brand tag, MPN tag, condition close ups, any flaws, included accessories, and packaging. The first photo (gallery image) carries the most weight in search result thumbnails.

What a ranking eBay listing looks like

Here is a real eBay structure that performs across categories.

Three things to notice. First, the title uses 78 of 80 characters with zero keyword repetition (every word is unique and pulls from a different buyer search). Second, 13 item specifics are filled, far more than most sellers bother with. Third, the description is short and focused on conversion, not SEO. Buyers searching “iPhone 13 Pro 256GB Sierra Blue Unlocked” find this. Buyers filtering “Apple, 256 GB, Sierra Blue, Unlocked” find this. The item specifics do the heavy lifting.

Item specifics deep dive

Item specifics are the most under used ranking signal in eBay SEO. Here’s how to use them.

Fill every relevant standard specific

eBay suggests dozens of standard item specifics per category. Most sellers fill 4 to 6 (brand, MPN, color, size, condition, model). Power sellers fill 12 to 20. The difference shows up immediately in filtered search. Cassini surfaces listings with complete item specifics on every filter combination buyers might apply.

Use custom item specifics for unique attributes

If your item has an attribute not in eBay’s standard list, add it as a custom item specific (40 character name, 65 character value). Examples:

• Custom name: “Battery Health”, Value: “89 percent”
• Custom name: “Original Box Included”, Value: “Yes”
• Custom name: “Region of Manufacture”, Value: “Made in USA”

Buyers use these in search refinement. Sellers who add them gain visibility on long tail searches that competitors miss.

Match the buyer search vocabulary

Item specific values should match how buyers actually search. “256 GB” not “256GB” because eBay normalizes “256 GB” with the space. “Sierra Blue” not “Blue” because Sierra Blue is the iPhone 13 Pro’s specific color name buyers type. “MPN” matches the manufacturer’s part number, not your internal SKU.

7 eBay mistakes that kill Cassini ranking

1. Stopping titles at 50 characters

Sellers leaving 30 of 80 characters unused. Cassini rewards 75+ character titles measurably. Fill the space with unique keywords every time.

2. Repeating keywords

“iPhone 13 Pro Apple iPhone 256GB Apple Pro” wastes characters and Cassini does not benefit from repetition. Each keyword should appear once in the title. The repeated word is dead weight.

3. Empty or skipped item specifics

The biggest hidden visibility killer on eBay. Filled item specifics drive filtered search visibility. Empty item specifics make the listing invisible to buyers who filter (which is most of eBay’s serious buying traffic).

4. Generic condition language

“Good” or “used” tells Cassini and buyers nothing. Use eBay’s structured condition options (New, New other, Open box, Manufacturer refurbished, Seller refurbished, Used, For parts) and pair with specific notes in the description.

5. Pasting descriptions full of HTML and links

Descriptions full of decorative HTML, animated gifs, and links to external sites slow load times and can trigger eBay’s listing quality penalties. Modern eBay descriptions should be plain text with light formatting (paragraphs, bullets, bold for key facts).

6. Wrong category

Listing an iPhone in “Cell Phones and Smartphones” instead of “Cell Phones and Smartphones > Apple.” Wrong category means missing buyers who browse by category tree. Cassini also weighs category accuracy.

7. Promotional language in titles

“FAST SHIPPING,” “L@@K,” “WOW,” “RARE!!!” These waste character space and Cassini may flag them as low quality signals. Use the title for keywords. Use the description (or eBay’s seller hub features) for promotional messaging.

How to write eBay listings with AI

Manually writing an optimized eBay listing takes 10 to 15 minutes per item: title research with 80 character optimization, item specifics filling field by field, description writing for conversion. Multiply across 30 items a week and that’s 5 to 7 hours of typing.

The QuickListAI eBay workflow drops that to roughly 60 to 90 seconds per item.

1. Open the eBay listing form in your browser. Open the QuickListAI Chrome extension side panel.
2. Describe the item (“iPhone 13 Pro 256GB Sierra Blue unlocked battery 89 percent excellent condition”) or upload a product photo.
3. Generate the listing. The AI builds an eBay tuned package: 78 to 80 character title with zero keyword repetition, full set of relevant item specifics suggested, and a buyer focused description.
4. Click Fill Listing. The extension fills the title, item specifics, and description directly on the eBay form.
5. Review and publish. Confirm the item specifics match your actual item, upload your photos, set price, hit publish.

For the full feature breakdown of the eBay tool, see the eBay AI Listing Generator page. For broader title strategy, see listing titles that rank. For the full picture across all 8 marketplaces, see the complete AI listing generator guide.

Crosslisting eBay with other marketplaces

eBay sellers most commonly crosslist to Mercari (similar US audience, faster shipping focus), Poshmark (for fashion specifically), Grailed (for menswear and streetwear), and Whatnot (for collectibles like cards and Funko Pops). Each platform has its own format rules, and eBay’s title and item specifics structure doesn’t translate directly.

The crosslisting workflow is covered in The Reseller’s Crosslisting Guide. For platform specific format quirks, see the guides for Mercari, Poshmark, and Grailed.

FAQ