Key Takeaways
The Highlights
Multi-CSS strategy delivered greater reach and campaign control
AI-powered optimisation drove targeting and bidding decisions
Incrementality testing validated that growth was net-new
Lower-priced product focus attracted first-time buyers and boosted lifetime value
The Challenge
As one of eBay’s longest-standing partners since the launch of CSS in 2017, Redbrain has contributed significantly to their CSS success. However, by 2024, the Shopping Ads landscape had become increasingly crowded and competitive. The challenge was how to efficiently attract new customers and re-engage dormant ones while maintaining sustainable growth and ROI. Rising auction pressure and aggressive bidding strategies made visibility more difficult. eBay needed a more agile and differentiated approach to drive incremental performance.
A core part of the evolving strategy focused on lower-priced products. These items serve as a natural entry point for new customers, who are more likely to make an initial purchase if the price is affordable. To support this approach, eBay offered enhanced incentives to partners like Redbrain to promote them more actively. This contributed to stronger visibility in lower-price categories and helped expand reach to price-conscious shoppers.
The Approach
- 01 / 03
Campaign Restructure
Focus on promoting lower-priced, high-conversion items
- 02 / 03
Dual-CSS Strategy
Redbrain deployed a dual-CSS strategy in the UK, setting up a second Comparison Shopping Service
- 03 / 03
Leveraged Google Tools
Redbrain leveraged advanced Google Tools to support efforts
eBay partnered with Redbrain to restructure campaigns and focus on promoting lower-priced, high-conversion items. Redbrain deployed a dual-CSS strategy in the UK, setting up a second Comparison Shopping Service to expand reach and segment campaign types more effectively. This allowed for greater coverage, more tailored bidding strategies, and access to untapped product categories.
To support these efforts, Redbrain leveraged several advanced Google tools:
- Google CSS for improved visibility in Shopping placements.
- tROAS (target Return on Ad Spend) bidding, applied selectively to optimise where automation aligned with campaign and performance goals.
- Multi-seller Merchant Center setup, allowing Redbrain to support multiple eBay sellers within a single structure.
Partnering with Redbrain:
Redbrain operates on a risk-free cost-per-sale model, meaning eBay only pays when a purchase occurs. Redbrain supported eBay’s efforts to scale Shopping Ads in the UK and Germany. The second CSS setup in the UK helped unlock new verticals and buyer segments, without duplicating existing internal efforts. These tests helped isolate the effect of Redbrain’s activity on new customer acquisition and sales, ensuring performance was additive and not duplicative.
The Results
The Results
This collaboration supported meaningful results. YOY GMV rose by +11% in 2024, with the UK and Germany leading growth through ASP boosting. Notably, Q1 2025 GMV surged +54% YoY, with the UK CSS growing +62% and Germany +84%. These results were supported by the expanded CSS infrastructure, improved campaign granularity, and refined targeting capabilities.
Incrementality testing confirmed that campaign growth was net new, rather than overlapping with other internal efforts.
Testimonials
Redbrain’s strategic campaign structure and focus on promoting entry-level products enabled us to unlock substantial new growth opportunities. Their second CSS launch gave us broader reach across more product categories, and their CPA model ensured efficiency at scale. Their commitment to incrementality testing gave us confidence that campaign performance was additive, not overlapping with existing activity. Redbrain continues to be an essential partner in our CSS success story.
Customer Testimonial
Rebecca Mangaroo
UK & AU Partnership Lead
Our long-standing partnership with eBay has always been about delivering sustainable, incremental growth. Through our CPA model and our focused strategy on promoting affordable, high-conversion products, we helped eBay reach new customers more efficiently. Launching a second CSS in the UK was a game-changer, unlocking new demand and reinforcing our commitment to innovative, results driven performance. With regular incrementality testing in place, we ensure our campaigns remain truly additive and aligned.
Partner Perspective
James Gibson
Director of Marketplaces
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