Turning data into results: How Meta Conversions API boosted campaign performance

Turning data into results: How Meta Conversions API boosted campaign performance

Global fashion eyewear brand Gentle Monster, faced the challenge of evolving privacy regulations and a reduced reliance on cookies, which were impacting the accuracy of their ad performance measurement.

Business challenge

As a trendsetter in the industry, Gentle Monster continuously seeks ways to refine its digital marketing strategies and better understand consumer behavior. To address the impact of changing privacy regulations and the diminishing role of cookies, the brand partnered with Jellyfish to find a data-driven solution that would deliver more precise performance insights and support their forward-thinking approach.

Jellyfish Solution

The Jellyfish Analytics team implemented a server-based Meta Conversions API (CAPI), reducing data loss from browser-transmitted pixel events and enabling high-quality data collection for improved targeting and measurement accuracy. To evaluate the impact of CAPI, the Jellyfish team carefully monitored Gentle Monster's always-on purchase campaigns, analyzing performance data before and after the CAPI implementation.

“With 3rd-party cookie restrictions limiting targeting, a solution was needed to minimize data loss and improve accuracy for high-engagement users. Implementing the server-based "Conversion API" enhanced data quality, significantly boosting ROAS.”

– Gentle Monster Marketing Manager

Impact

The adoption of Meta Conversions API helped Gentle Monster successfully navigate the challenges of a privacy-first digital landscape, driving measurable growth in advertising efficiency:

  • Improved Reporting Accuracy: The API captured a higher volume of purchase events, providing a more complete picture of campaign performance.
  • Enhanced ROAS: With better data accuracy, Gentle Monster achieved significant improvements in Return on Ad Spend (ROAS).
  • Smarter Campaign Optimization: The additional data allowed for more effective bidding strategies and sharper audience targeting.

Results

122%

Increase in Return on Ad spend

50%

Decrease in average CPA (Purchase)

52%

Additional Purchase conversion reported

Resources

2 Apr 2026John Dawson

You need to plan around Context Entry Points

Marketers use Category Entry Points to understand how their brand comes to mind when people enter an occasion. But with the growth of AI models, John Dawson, VP of BrandStrategy, explains why brands must move that thinking to encompass a new player, introducing Context Entry Points.

Read Article
25 Mar 2026Jellyfish

Jellyfish Honored on Fast Company's Most Innovative Companies List

Recognized for engineering a social campaign which blurred the lines between the severed world and our own, to promote Season 2 of Severance, and an unprecedented fourth listing in five years for The Brandtech Group.

Read News
24 Mar 2026Dillan Ramrattan

Data Strength: The New Foundation for Business Reliability

For years, marketing relied on a "gold standard" of tracking that felt bulletproof. But in 2026, that foundation is cracking. If your data feels "leaky," it’s because it is. Dillan Ramratten, Analytics Director explains why brands aren't just facing a glitch; they are facing a total shift in how measurement works.

Read Article

Up Next

The Deadly Billboard marks Final Destination Return

To mark the 25th anniversary of the cult horror franchise, Final Destination returned in 2025 with Final Destination: Bloodlines. Warner Bros partnered with Jellyfish to design a bold, eerie activation designed to reintroduce the saga and tap into Gen Z's taste for twisted thrills.

Read More