Marketplace SEO: Amazon, eBay & Beyond

Marketplace SEO is a different game from website SEO. The algorithms are different, the ranking factors are different, and the strategy is different. But the underlying principle is the same: understand what the platform rewards and optimise for it.

I work with ecommerce brands that sell across their own site, Amazon, eBay, and niche marketplaces. Here's what actually moves the needle on each.

Amazon SEO: The A10 Algorithm

Amazon's search algorithm (commonly called A10, though Amazon doesn't officially name it) prioritises one thing above all else: purchase likelihood. Unlike Google, which tries to match informational and navigational intent, Amazon assumes every search is transactional.

Amazon Ranking Factors

Sales velocity — The most important factor. Products that sell more rank higher. This creates a compounding effect that makes established products hard to displace.
Keyword relevance — Amazon matches your listing content against the search query. Exact match and phrase match in your title carry the most weight.
Conversion rate — Your listing's conversion rate relative to competitors for the same keyword. Higher CVR = higher ranking.
Reviews and ratings — Both quantity and quality. Products with more reviews and higher ratings rank better.
Fulfilment method — FBA (Fulfilled by Amazon) listings get a ranking boost over FBM (Fulfilled by Merchant) for Prime-eligible searches.
Price competitiveness — Amazon monitors your price relative to competitors and other channels.

Optimising Amazon Listings

Product Title

Amazon titles can be up to 200 characters (varies by category). Use the full allowance. Structure it as:

[Brand] + [Core Keyword] + [Key Feature 1] + [Key Feature 2] + [Size/Quantity/Variant]

Example: "TrailPro Ultra Running Shoes Men's Waterproof Trail Runners Lightweight Anti-Slip Outdoor Hiking Shoes Size 9-13"

Front-load the most important keyword. Amazon's algorithm gives more weight to words appearing earlier in the title.

Bullet Points (Key Features)

You get 5 bullet points. Each should:

Lead with a benefit, not a feature
Include relevant keywords naturally
Be 100-200 characters (Amazon truncates on mobile)
Address a specific buyer concern or use case

Backend Search Terms

Amazon gives you a hidden field (up to 249 bytes) for search terms that don't appear in your listing. Use this for:

Synonyms and spelling variations
Related terms you couldn't fit in the title
Common misspellings
Spanish or other language terms (if selling in multicultural markets)

Don't repeat keywords already in your title or bullets — it's wasted space.

A+ Content (Enhanced Brand Content)

If you're brand-registered, use A+ Content to add rich media and comparison charts to your listing. A+ Content doesn't directly impact Amazon search rankings, but it improves conversion rate — which does impact rankings.

eBay SEO: Cassini Algorithm

eBay's Cassini algorithm is less sophisticated than Amazon's but has its own quirks.

eBay Ranking Factors

Listing quality score — Complete item specifics, high-quality images, detailed description
Seller performance — Feedback rating, defect rate, late shipment rate
Price + shipping — Total cost competitiveness matters. Free shipping listings often rank higher.
Sell-through rate — How often your listing converts relative to views
Recency — Newer listings get a temporary ranking boost

eBay Optimisation Tactics

Complete every item specific — eBay provides category-specific fields (brand, colour, size, material). Fill every single one. Incomplete item specifics are the #1 reason eBay listings underperform.
Use eBay's keyword tool (Terapeak) — Included free with eBay stores. Shows search volume, sell-through rate, and pricing data for keywords in your category.
Offer free shipping — Build shipping cost into the item price. eBay's algorithm favours free shipping listings.
Use Fixed Price format — Auction-style listings rank lower for commercial searches. Use Buy It Now for SEO visibility.

Google Shopping and Marketplace Listings

Here's something many marketplace sellers miss: your Amazon and eBay listings can appear in Google search results and Google Shopping. Google increasingly indexes marketplace product pages.

This means your marketplace listing optimisation has dual benefits — it helps you rank within the marketplace AND can drive Google organic traffic to your marketplace listings.

To maximise this:

Ensure your product titles are keyword-rich (they become the Google listing title)
Use high-quality primary images (they appear in Google Shopping)
Keep pricing competitive (Google Shopping shows prices prominently)
Submit a Google Merchant Center feed even if you primarily sell on marketplaces

Multi-Channel Strategy: Marketplace vs Own Site

The biggest strategic question for ecommerce brands: should you invest in marketplace SEO, own-site SEO, or both?

When to Prioritise Marketplace SEO

You're in a product category where Amazon/eBay dominate the Google SERPs
You're a new brand without domain authority
Your product category has high marketplace search volume
You need revenue quickly (marketplace organic can ramp faster than website organic)

When to Prioritise Own-Site SEO

You want to own the customer relationship and data
Your margins can't absorb marketplace fees (typically 15-30%)
You're building a brand, not just selling products
You want to build content and topical authority that compounds over time
Your competitors' own sites rank well (proving it's possible in your category)

The Hybrid Approach

Most successful ecommerce brands do both. The strategy I recommend as an ecommerce SEO consultant:

Use marketplaces for product discovery — Marketplace SEO captures high-intent buyers searching within the platform.
Use your own site for content and authority — Blog content, buying guides, and category pages build organic authority that marketplaces can't replicate.
Drive marketplace customers to your ecosystem — Package inserts, email follow-ups (within marketplace rules), and brand building encourage repeat purchases on your own site.

Niche Marketplaces Worth Optimising For

Beyond Amazon and eBay, consider these platforms depending on your category:

Etsy — Handmade, vintage, and unique items. Etsy SEO heavily weights tags (13 per listing), title keywords, and listing freshness.
Catch (Australia) — Major Australian marketplace. Less sophisticated algorithm — focus on pricing, images, and complete product data.
The Iconic/Kogan — Australian fashion and general merchandise. Category-specific optimisation with emphasis on brand authority.
Google Shopping (free listings) — Not technically a marketplace, but free product listings in Google Shopping are an under-utilised channel for many brands.

AI Search and Marketplace Visibility

AI search tools like ChatGPT, Perplexity, and Google's SGE are increasingly recommending specific products. These recommendations often pull from marketplace data because it's structured, comprehensive, and includes pricing.

Your marketplace listings are essentially training data for AI product recommendations. Ensure your listings have:

Complete and accurate product specifications
Clear differentiation from competitors in the description
Strong review profiles (AI tools often reference review sentiment)
Competitive pricing (AI tools frequently surface price comparisons)

For more on how AI search is changing ecommerce, see my guide on AI SEO for ecommerce.

Managing SEO Across Multiple Channels

The operational challenge of multi-channel marketplace SEO is real. Here's how to stay efficient:

Centralise product data — Use a PIM (Product Information Management) system or structured spreadsheet as the source of truth for all product content.
Adapt, don't duplicate — Each platform has different title length limits, description formats, and keyword fields. Write platform-specific variations from your centralised data.
Monitor cannibalisation — If your Amazon listing and own-site page compete for the same Google keyword, check which one performs better and consider consolidating your strategy for that term.
Track performance per channel — Know your organic conversion rate, revenue per session, and keyword rankings on each platform independently.

Frequently Asked Questions

Can I use the same product descriptions on my site and Amazon?

Technically yes, but it's not ideal. Amazon listings and website product pages serve different contexts. Amazon descriptions should be dense with features and keywords. Website descriptions can be more narrative and brand-focused. If you must choose one to make unique, prioritise your own site — that's the one Google will index for organic search.

Does Amazon SEO affect Google rankings?

Indirectly, yes. Amazon product pages frequently rank in Google search results. A well-optimised Amazon listing can appear in Google organic results and Google Shopping, giving you visibility even when your own site doesn't rank for that keyword.

How long does it take to rank on Amazon?

New product listings typically need 2-4 weeks to stabilise in Amazon's algorithm. Significant ranking improvements for competitive keywords usually require 3-6 months of consistent sales velocity and review accumulation.

Should I run Amazon PPC to support organic ranking?

Yes. Amazon PPC drives sales, which directly impacts organic ranking. Most successful Amazon sellers use PPC strategically on launch and for competitive keywords, then reduce spend as organic rankings improve. The keyword data from PPC campaigns also informs your organic listing optimisation.