Customer Stories / Engineering, Construction & Real Estate / Americas

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Achieving 30-Millisecond Search Results Using Amazon OpenSearch Service with CoStar Group

Learn how CoStar Group, a leading provider of online real estate marketplaces, information, and analytics, increased speed and scalability for using Amazon OpenSearch Service and other AWS services.

30-millisecond average time

to return search results

4-second average time

to update listings

50 million

monthly active users supported

4x less costly

than an on-premises solution

Modernized infrastructure

for ease of future growth


CoStar Group (CoStar), a real estate information and analytics provider, was planning the launch of to provide residential real estate data for more than 200 million properties. Recognizing the need to modernize its data strategy, CoStar embarked on a migration from on-premises infrastructure to the cloud with support from Amazon Web Services (AWS). CoStar built a data plane using AWS services to seamlessly integrate and unify the data driving its real estate products, while catering to the speed and scalability requirements of modern, interactive websites for customers.

Using AWS services, CoStar’s data plane keeps data for the company’s products current and updated in near real time, standardizes data access for developers, and facilitates rapid innovation and expedited product delivery.

Shriram-Housing Finance-Limited-case-study

Opportunity | Using AWS Services to Launch a Modernized Data Plane in 1 Year That Supports More Listings and Faster Load Times for CoStar

Founded in 1987, CoStar conducts expansive, ongoing research to produce and maintain a comprehensive database of real estate information. It provides commercial real estate information, analytics, and news to professionals around the world. In 2014, CoStar acquired as a complement to its commercial real estate offerings. The company further expanded into residential real estate in 2021 with the acquisition of

CoStar’s commercial real estate data systems were powered by an on-premises data center with 6,000 servers; however, needed to support more listings with increased data sources and faster load times than the on-premises solution could handle. For commercial real estate data, CoStar needed to support millions of properties and tens of thousands of users. Meanwhile, with residential data, CoStar needed to scale to support hundreds of millions of properties with millions of daily users. In August 2021, the company chose AWS because of the scalability, performance, and ease of use that CoStar found through comprehensive testing. CoStar launched with its modernized data plane 1 year later, in August 2022.


We plan to use the data plane, built on AWS, elsewhere to achieve the scalability and speed of getting data from the source system to applications in seconds rather than minutes or hours.”

Andy Ventura
Vice President of Software Development Engineering, CoStar Group

Solution | Increasing Scalability, Averaging 30-Millisecond Search Results, and Reducing Costs Using Amazon OpenSearch Service

CoStar uses the data plane, a system of AWS native services, to unify data and provide data as a service to its developers. CoStar uses Amazon Elastic Kubernetes Service (Amazon EKS)—a managed service to start, run, and scale Kubernetes on AWS and in on-premises data centers—for the company’s containerized applications to build a model topic and put data into a database type that is most relevant to the developers’ needs. To provide the most up-to-date data for developers, CoStar actively tracks and updates model topics that contain the data for the model using data replication chains. Developers query and consume domain data like listings, agents, and properties using representational state transfer (RESTful) interfaces. By using RESTful interfaces rather than manually checking multiple services for data updates, developers have faster access to data, which facilitates innovation and accelerates the company’s product delivery.

For, speed and scalability are important, given the volume of listings and concurrent customer queries. The data plane needs to stay current with updates from the residential multiple-listing service systems, data provided by users of, and CoStar’s own internal analysts’ data. When data enters the data plane and is in a model topic search, every millisecond counts because users expect to see the most up-to-date information.

In most use cases, CoStar stores model topic data using Amazon DynamoDB, a fully managed, serverless, key-value NoSQL database service for single-digit millisecond performance at virtually any scale. “Compute is expensive, but storage is not. By keeping objects cached in services like Amazon DynamoDB, we can avoid actively building the object and processing the data each time when new data requests come in,” says Andy Ventura, vice president of software development engineering at CoStar. CoStar stores model topic data that doesn’t change frequently or doesn’t need rapid access using Amazon Simple Storage Service (Amazon S3), an object storage service offering industry-leading scalability, data availability, security, and performance. With this infrastructure, the company updates listings in 4 seconds on average, which is important for price and availability changes. It’s significantly faster than the on-premises solution, which took 6–30 minutes to update real estate listings. “When our competitors advertised that they could update listings in minutes, we challenged ourselves to do it in seconds,” says Ventura. “We’ve achieved that using AWS.”

To provide search results across multiple fields—such as number of bedrooms and bathrooms, price, and location—CoStar uses Amazon OpenSearch Service to securely unlock near-real-time search, monitoring, and analysis of business and operational data. Even with up to 50 million monthly active users on, CoStar can return search results in an average of 30 milliseconds using Amazon OpenSearch Service. “In terms of search engine optimization, every millisecond counts,” says Ventura. Prior to using AWS, CoStar would have needed to build a system to handle peak traffic. Using the elastic nature of AWS services, the data plane can scale as needed, depending on the number of users accessing or the number of data elements being updated in model topics.

CoStar also saves on infrastructure and developer costs by using managed AWS services. Instead of maintaining additional staff or acquiring the necessary equipment, CoStar reduces the complexity of its systems and gets data to applications that need it in near real time. The company estimates that an on-premises solution to build the data plane would have started at four times the cost. “We can’t do the types of configurations that we need to do on premises, and we would have needed more employees to manage the servers and racks,” says Ventura. “It was a no-brainer for us to use AWS.”

Outcome | Facilitating New Business Models by Retrieving Data in Seconds Rather than Minutes or Hours Using AWS Services

CoStar’s data plane helped modernize the infrastructure with a solution that is simple to spin up in other regions and facilitates new business models. CoStar plans to fully migrate to the cloud and use the data plane across its business in the future. “We plan to use the data plane, built on AWS, elsewhere to achieve the scalability and speed of getting data from the source system to applications in seconds rather than minutes or hours,” says Ventura.

About CoStar Group

CoStar Group provides commercial real estate information, analytics, and news to entities like government agencies and real estate brokerages around the world. The company expanded to offer residential real estate data from websites like

AWS Services Used

Amazon EKS

Amazon Elastic Kubernetes Service (Amazon EKS) is a managed Kubernetes service to run Kubernetes in the AWS cloud and on-premises data centers.

Learn more »

Amazon DynamoDB

Amazon DynamoDB is a fully managed, serverless, key-value NoSQL database designed to run high-performance applications at any scale.

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Amazon S3

Amazon Simple Storage Service (Amazon S3) is an object storage service offering industry-leading scalability, data availability, security, and performance.

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Amazon OpenSearch Service

Amazon OpenSearch Service makes it easy for you to perform interactive log analytics, real-time application monitoring, website search, and more.

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