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

21 May 2026Jellyfish

HOKA turns Hackney Half into a live canvas celebrating the intersection of running and culture

HOKA partnered with Jellyfish to launch "Let's Fly Hackney," an experiential, multichannel campaign in celebration of its support of the HOKA Hackney Half Marathon. From an evolving mural and a Lime bike takeover to Citymapper activations and free recovery rides in branded black cabs, we embedded HOKA right into the fabric of Hackney culture.

Read News
11 May 2026Jellyfish

New leadership: Stephanie Parry moves into new role as UK&I Managing Director

We are thrilled to announce a significant leadership transition within our UK operations. Stephanie Parry has been appointed as our new UK&I Managing Director, succeeding Nick Fettiplace, who is departing Jellyfish after a remarkable fourteen-year journey. Since joining Jellyfish in 2023 as EVP Client Management, Stephanie has successfully led accounts for major clients including Boots, Deckers, Apple, and Workday.

Read News
22 Apr 2026Jellyfish

Jellyfish Named 2026 Google Cloud Partner of the Year for Training in North America

We’re thrilled to announce that Jellyfish has earned the prestigious 2026 Google Cloud Partner of the Year in the Training: North America category. This recognition from Google Cloud highlights Jellyfish’s continued leadership in enabling organizations to unlock the full value of Google Cloud through world-class training, upskilling, and certification programs.

Read News

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