CallApp is a global caller ID and call blocker app with more than 50 million active users worldwide. As the company expanded globally, its monetization team faced a growing challenge: how to monetize traffic in every market while maintaining a scalable setup.

By integrating BidMachine's bidding solution, CallApp brought more advertiser demand to underserved markets, increased auction competition and improved monetization performance.

The challenge: monetizing a global user base

While CallApp had strong advertiser demand in major markets, many countries suffered from limited ad coverage. Users were active and ad placements were available, but demand was often inconsistent or unavailable. As Jonathan Farber, Head of Monetization and User Acquisition at CallApp, explains:

“We have users around the world, and we needed to monetize all of them. We had a lot of ‘empty’ countries where there were placements and people to see ads, but not enough demand.”

At the same time, managing demand partners through individual integrations added operational complexity. The team wanted access to more advertisers without creating additional overhead.

Expanding demand and simplifying monetization

CallApp added BidMachine to its bidding-based monetization strategy. The team relies exclusively on in-app bidding and continuously looks for ways to increase competition within its auctions. With BidMachine, CallApp gained a single access point to additional demand sources and benefited from the platform's extensive network of partners and integrations.

“Now we have a lot of different contracts and partnerships without having to integrate with each network directly. That really makes our lives easier.”

The integration also helped solve CallApp's geographic coverage gaps by introducing advertiser demand in markets that were previously difficult to monetize. According to Farber:

“BidMachine helped us monetize users in more countries and reach markets where we previously had limited demand.”

More competition, higher bids

For CallApp, adding BidMachine meant increasing competition inside the auction. Because all demand sources compete in real time, every additional bidder creates more opportunities to maximize impression value.

“As many bidders as we add, we get a better price. Before we worked with BidMachine, our bids were good but relatively low. BidMachine gave us a lot of competition and increased our revenue directly.”

Results

Since implementing BidMachine, CallApp has seen improvements in its key monetization metrics:

• Fill rates and CPMs increased by 7%
• Revenue grew by 3%

Farber summarizes the impact:

“BidMachine made us much more competitive. It increased our revenue and helped us grow the business.”

Maintaining user experience while scaling monetization

For CallApp, monetization growth must be balanced against user experience. While the company continues to optimize placements and ad strategy, BidMachine delivered incremental revenue without negatively affecting users.

Early analysis indicates:

• User retention and engagement remained stable
• Ad quality was consistent with the team's existing monetization standards

What surprised CallApp most

Beyond performance, CallApp highlighted the consistency of both the partnership and results. In an industry often characterized by frequent account turnover and fluctuating performance, the company pointed to BidMachine's stability as a key differentiator.

“I'm surprised we've had the same account manager for so many years. Usually, you get a different person every six months.”

Farber also noted BidMachine's steady revenue contribution:

“BidMachine is constantly very good and even increasing from month to month.”

What's next

With monetization infrastructure largely in place and fill rates approaching full coverage across many markets, CallApp can now dedicate more resources toward growth initiatives. The team continues to invest heavily in user acquisition while optimizing placements, bidding performance and product experience.

Additionally, after seeing strong results on Android, CallApp recently began testing BidMachine on iOS as part of its next phase of monetization expansion.

Advice to other publishers

Farber's recommendation is straightforward:

“If you work with a bidding system, BidMachine is a must.”

For publishers looking to improve global fill rates, increase auction competition and simplify monetization operations, CallApp's experience demonstrates how additional demand and bidding competition can translate directly into revenue growth.