In 2018, Yelp switched from using the MVP architecture to the MVI architecture for Android development. Since then, adoption of our new MVI architecture library has risen and we’ve seen some great performance and scalability wins. In this blog post, we’ll cover why we switched to MVI in the first place, how we managed to get performant screens by default, and our take on unit testing MVI. What is MVI? One of the main reasons to use an architecture is to make things easier to test by separating concerns. For Android, this means keeping the Android SDK out of our...

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Yelp aims to offer easily accessible high-quality content. We need to tag, organize and rank online content to attain this goal. For this purpose, Yelp engineers have started using general embeddings on different data. It improves usability and efficiency for all kinds of model development. Having embeddings that encapsulate semantic information readily available for the massive amounts of data Yelp owns makes implementing new deep learning models easier, since it can serve as an excellent baseline for any model input. This blog post discusses how the Content and Contributor Intelligence team generates low-dimensional representations of review text, business information and...

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The Yelp website serves millions of users and business owners each day, and engineers in our product teams are constantly adding and improving features across hundreds of pages. Webcore, Yelp’s frontend infrastructure team, is always looking to ensure that web developers can ship their changes quickly and safely, without the burden of maintaining complex team-specific infrastructure. To achieve this, we made some significant changes to our internal deployment model for React pages in late 2019. This blog post will explain why we made these changes, describe the new architecture we implemented, and share some of the lessons we learned along...

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Robots are frequently used in the manufacturing industry for numerous use-cases. Amongst many, one case is to eliminate defective products automatically from reaching the finished goods inventory. The same principles of these systems can be adopted to filter out malformed data from datastores. This blog post deep dives into how we rebuilt one of our Cassandra(C*) clusters by removing malformed data using Yelp’s Data Pipeline. Apache Cassandra is a distributed wide-column NoSQL datastore and is used at Yelp for storing both primary and derived data. Many different features on Yelp are powered by Cassandra. Yelp orchestrates Cassandra clusters on Kubernetes...

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Manually managing the lifecycle of Kubernetes nodes can become difficult as the cluster scales. Especially if your clusters are multi-tenant and self-managed. You may need to replace nodes for various reasons, such as OS upgrades and security patches. One of the biggest challenges is how to terminate nodes without disturbing tenants. In this post, I’ll describe the problems we encountered administering Yelp’s clusters and the solutions we implemented. Problems At Yelp we use PaaSTA for building, deploying and running services. Initially, PaaSTA just supported stateless services. This meant it was relatively easy to replace nodes since we only needed to...

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Abstract   Compared to full-scale ML, multi-armed bandit is a lighter weight solution that can help teams quickly optimize their product features without major commitments. However, bandits need to have a candidate selection step when they have too many items to choose from. Using A/B testing to optimize the candidate selection step causes new bandit bias and convergence selection bias. New bandit bias occurs when we try to compare new bandits with established ones in an experiment; convergence selection bias creeps in when we try to solve the new bandit bias by defining and selecting established bandits. We discuss our...

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In this blog post, we introduce Spark-Lineage, an in-house product to track and visualize how data at Yelp is processed, stored, and transferred among our services. What is Spark-Lineage? Spark and Spark-ETL: At Yelp, Spark is considered a first-class citizen, handling batch jobs in all corners, from crunching reviews to identify similar restaurants in the same area, to performing reporting analytics about optimizing local business search. Spark-ETL is our inhouse wrapper around Spark, providing high-level APIs to run Spark batch jobs and abstracting away the complexity of Spark. Spark-ETL is used extensively at Yelp, helping save time that our engineers...

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At Yelp, we have a reasonably large Android community for a company of Yelp’s size. These talented and skilled Android engineers work on Yelp’s client and business applications. We would like to share some of the unique challenges that we’ve experienced along with our various efforts to overcome those challenges. Analytics Infra is a team at Yelp that works on experimentation and logging platforms and supports them across the entire Yelp ecosystem. Within the Analytics Infra team, we have an Android working group. You may consider our team as an infrastructure team - a team that implements end-user functionality -...

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