Carousell: Using Google Cloud to run regional classifieds marketplace with tens of millions of users

About Carousell

Carousell is a classifieds marketplace that makes selling as easy as taking a photo, buying as simple as chatting. Launched in August 2012, Carousell began in Singapore and is now one of the world's largest and fastest-growing marketplaces in eight markets across Southeast Asia, Taiwan and Hong Kong. Carousell is backed by leading investors, including Telenor Group, Rakuten Ventures, Naver, and Sequoia Capital. The Carousell marketplace has a diverse range of products across a variety of categories, including cars, lifestyle, gadgets and fashion accessories. Download the app for iOS or Android, and visit www.carousell.com for more information.

Industries: Other
Location: Singapore

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With Google Cloud, Carousell can scale an online classifieds marketplace used by tens of millions of people to buy, sell, and chat into new regional and global markets. The business can also deliver a common dataset to ensure consistent reporting and analysis.

Google Cloud results

  • Maintains systems engineering team at five people despite 200%+ growth in business
  • Enables engineering team members to spend 70% of their time on innovation and large projects rather than infrastructure tasks
  • Provides a single set of data to support decision-making across the business

Supports tens of millions of users across eight markets and achieves a valuation of US$900 million

Founded in 2012 and headquartered in Singapore, Carousell operates a mobile classifieds marketplace that enables users to list products and services in just 30 seconds. Users take photos, add descriptions, and conduct in-app conversations to obtain information and buy from other users.

The business evolved to a mobile classifieds from an initial focus on printed advertisements and online forums and gained sufficient traction in its home market that one in four of the population regularly uses the platform. “We’ve grown as a business from three founders who didn’t take any remuneration for 18 months to a workforce of 400+ people in the Carousell business alone, and have made several regional acquisitions,” says Victor Neo, Carousell’s Director of Engineering. “We are one of the fastest-growing marketplaces in eight markets across Southeast Asia, Taiwan, and Hong Kong.”

Individual holds mobile phone which at top displays "Recommended seller" and below that "Explore Carousell" with a serices of icons and "Your daily pics" with a series of photos

Carousell initially ran its classifieds marketplace on a variety of hosted services. However, as the marketplace exploded in popularity, this infrastructure became unable to meet the business's requirement for a stable, scalable, reliable, and cost-effective technology platform.

“We recruited some talented people into our infrastructure team, and they had a remit to improve the stability of our service,” says Victor. The team evaluated cloud providers' I/O, compute, and price offerings, and determined Google Cloud best met Carousell's needs.

“Google Cloud provided a fine degree of control over instance configurations at an attractive price point and delivered the freedom to adapt our cloud architecture easily to accommodate changes to the business,” says Victor. “We also saw using Kubernetes as a key piece of the puzzle in helping us reduce our maintenance requirements.”

Carousell could also work directly with Google Cloud product managers and engineers to apply services and resources to its use cases.

The business moved quickly to migrate its applications and workloads to the cloud platform. The engineering team completed the initial project in two weeks before fine-tuning the architecture to optimize performance, reliability, and cost-effectiveness.

“Google Kubernetes Engine enables our engineers to focus 90% of their time on a single code base and let the product handle application scaling for them.”

Victor Neo, Director of Engineering, Carousell

Integrating acquired businesses

In recent years, the business acquired similar and complementary organizations across the region, and now the Carousell Group comprises companies and platforms such as Carousell, Mudah in Malaysia, Chotot in Vietnam, and OneKyat in Myanmar.

“We have been moving Carousell team members to work more closely with our fellow teammates from Mudah and Chotot, and one of the areas we worked on together in early 2020 was to help accelerate Mudah and Chotot’s workload migration from on-premises servers to Google Cloud,” says Victor. The business aims to complete the migration of all its businesses to a standard technology stack by the end of 2021.

Carousell uses a range of Google Cloud services, including Compute Engine to access compute resources to run PostgreSQL databases instances, Cloud Load Balancing to distribute cloud resources effectively, and App Engine to develop and host applications in the cloud. Cloud Storage hosts static assets such as images and videos for listings to provide fast write-access for Carousell’s services. Persistent Disk provides block storage for Compute Engine instances and Dataflow runs certain batch processing jobs.

“We want to make sure every worker can access the same set of data we use to make decisions and measure key metrics down to the metrics we have for each product and feature we have. Having a BigQuery data warehouse means we can handle large volumes of data and concurrent queries and focus on query optimization rather than scalability.”

Victor Neo, Director of Engineering, Carousell

Moving to Google Kubernetes Engine

The business subsequently used Docker to isolate applications and services from their environments and began running a Kubernetes cluster on Compute Engine. However, the time and resource savings available by automating the management and scaling of clusters through Google Kubernetes Engine proved compelling, and Carousell now uses the service to run all its in house-developed applications and code. The Carousell platform back end and messaging layer built in Apache Kafka now runs in Kubernetes.

With Google Kubernetes Engine, the business can scale seamlessly to support demand peaks and sustained growth. The service stops and restarts the preemptible virtual machine instances used to minimize costs as part of the 50–100 cluster size changes required during intensive customer usage. “Google Kubernetes Engine enables our engineers to focus 90% of their time on a single code base and let the product handle application scaling for them,” says Neo.

The business also uses BigQuery to provide a scalable analytics data warehouse, with Looker enabling Carousell team members to analyze and derive insights from datasets and Google Data Studio providing interactive dashboards and reports to support technology leaders’ decision-making. BigQuery hosts almost all the data Carousell uses for analysis and production.

“We want to make sure every worker can access the same set of data we use to make decisions and measure key metrics down to the metrics we have for each product and feature we have,” says Victor. “Having a BigQuery data warehouse means we can handle large volumes of data and concurrent queries and focus on query optimization rather than scalability.

“In addition, using Looker with BigQuery means we can deliver our critical daily and weekly business reports without incident.”

“Google Cloud will continue to be the foundation of all our engineering work and allow us to scale applications to users worldwide.”

Victor Neo, Director of Engineering, Carousell

Listings grow to 250 million+

When listing numbers had reached 80 million in 2017, Carousell estimated that, had it used an on-premises infrastructure rather than the cloud, it would have had to increase the engineering team, responsible for system maintenance and uptime, from five to 30 people. Victor points out that the team has remained the same size, despite the number of listings growing to over 250 million in 2019, bringing additional user interaction and activity.

Furthermore, rather than spend up to 70% of its time manually changing cluster sizes to accommodate fluctuations in demand, the engineering team can now participate in design discussions and work on major projects. “With Google Cloud, the team can spend up to 70% of its time working on major projects such as creating a configuration that allows us to reproduce the entire Carousell app and environment for testing, experimentation, and innovation,” says Victor.

For productivity and prompt, reliable communication within its business, customers, and stakeholders, Carousell continues to rely on Google Workspace. “The nice thing about Google Workspace is it’s an inexpensive set of tools that enables you to scale email and other productivity tools in a cost-effective way,” says Victor.

He believes Google Cloud will continue to underpin Carousell’s quest to become a world leader in classifieds marketplaces, delivering a strong foothold in ASEAN and a presence in the rest of the world. “Google Cloud will continue to be the foundation of all our engineering work and allow us to scale applications to users worldwide,” he concludes.

Two people stand holding mobile phones displaying the Carousell mobile app

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About Carousell

Carousell is a classifieds marketplace that makes selling as easy as taking a photo, buying as simple as chatting. Launched in August 2012, Carousell began in Singapore and is now one of the world's largest and fastest-growing marketplaces in eight markets across Southeast Asia, Taiwan and Hong Kong. Carousell is backed by leading investors, including Telenor Group, Rakuten Ventures, Naver, and Sequoia Capital. The Carousell marketplace has a diverse range of products across a variety of categories, including cars, lifestyle, gadgets and fashion accessories. Download the app for iOS or Android, and visit www.carousell.com for more information.

Industries: Other
Location: Singapore