Cloud cost visibility with ClickHouse

At Capital One, we think of cost visibility as an innovation driver—not just a finance function.

In a world where cloud spend can scale as fast as your ideas, it’s not enough to just keep costs down. You need to know what you’re spending, why it matters and how it drives customer impact. That’s why cloud cost transparency is a core pillar of our technology approach.

To help enable innovation, we frequently seek out open source tools that can scale, evolve fast and invite us to contribute back. And when it comes to getting deep, real-time visibility into how our cloud infrastructure is used—and how that usage evolves—open source ClickHouse has become an important tool in our toolkit.

ClickHouse is an open source, high-performance database built for speed and scale. Its columnar architecture makes it a natural fit for analytical workloads—including the large, complex datasets we generate from cloud resource utilization, billing events and system telemetry.

Here’s what caught our attention:

• Speed: Delivers sub-second responses to complex queries, making it ideal for real-time dashboards, anomaly detection and more.

• Scale: Executes queries across billions of rows per server, easily handling environments with massive data ingestion and demanding query workloads.

• Efficiency by Design: Reduces compute and storage footprints through advanced techniques like columnar compression and vectorized execution. This directly supports our goal of keeping cloud costs low—even as we monitor cost data itself.

• MergeTree Engine: The MergeTree storage engine ensures efficient data insertion and querying through advanced data partitioning, replication and primary key indexing. ClickHouse uses this to maintain performance as data volumes grow.

• Rich SQL Support: Offers a comprehensive SQL dialect with support for arrays, nested data and advanced analytical functions, allowing for sophisticated analysis directly within the database.

We’re also drawn to technologies that are open, community-driven and evolving with the market. ClickHouse’s open source is actively developed and battle-tested by a broad ecosystem, which makes it easier for us to trust, extend and contribute back.

ClickHouse's technical advantages have led to strong adoption across industries, including:

• E-commerce – customer behavior analysis, inventory management and personalized recommendations.

• IoT – processing and analyzing vast amounts of sensor data in real time, enabling predictive maintenance and operational efficiency.

• Customer-facing analytics – customer dashboards, interactive applications and more.

• Observability – building backend for observability platforms to monitor system health and surface performance issues quickly.

At Capital One, we want to give teams the data they need—when they need it—to make informed FinOps decisions. With ClickHouse, we can:

• Spot trends early — surfacing anomalies before they hit the bottom line

• Foster shared accountability — making cloud usage visible across teams

• Plan smarter — using historical data to guide investment, not just react to it

To be clear, these outcomes require more than just a database. They require an intentional architecture, a shared data culture and the ability to move fast without losing sight of cost.

However, we believe that open source tools like ClickHouse—when used responsibly—can help unlock innovation, increase transparency and give us the freedom to build the systems that work best for our business.

Our use of ClickHouse is just one piece of a larger story. 

Capital One is building a culture of engineering excellence where we don’t just adopt open source technologies—we rally around them.  Open source tools help accelerate development cycles, increase transparency and enable us to be part of broader conversations happening in the tech community.

Leveraging those tools to help us solve real challenges—like making cloud costs visible in near real time—makes it a win for everyone.  For us, cost visibility isn’t just about controlling spend—it’s about enabling better decisions to better serve our customers.

As our infrastructure evolves, we’ll keep building with tools that help teams stay fast, focused and financially aware.