DoorDash Engineering Blog

Backend

Speeding Up Redis with Compression

One of challenges we face almost everyday is to keep our API latency low. While the problem sounds simple on the surface, it gets interesting sometimes. One of our endpoints that serves restaurant menus to our consumers had high p99 latency numbers. Since it’s a high traffic endpoint we naturally use caching pretty intensively. We ...

Enforce Timeout: A DoorDash Reliability Methodology

“What would happen if we removed statement timeouts in our Postgresql databases?” That’s one of the questions asked in a management meeting. At the time I only responded that it would be bad — it would cause problems and make it harder to debug. However, I realize now that this is a topic that many people don’t ...

Contract Testing with Pact

Introduction As we migrate our systems to a microservices-oriented architecture at DoorDash, we have taken care to balance the excitement around anticipated benefits (development velocity, deployment independence, etc.) with a more measured assessment of our preparedness to work with the complexities introduced by more distributed systems. One of the most common pain points with microservices — or, ...

Reinforcement Learning for On-Demand Logistics

Overview Introduction What is the assignment problem at DoorDash? What is reinforcement learning? Reinforcement learned assignment Moving forward Conclusion Introduction DoorDash recently held our thirteenth hackathon. Hackathons are our opportunity to explore new technologies and moon-shot ideas; they help us stay up-to-date with the world and think 10x. At DoorDash, we’re constantly thinking of ways ...

My Engineering Internship Experience at DoorDash

Walking into the cafeteria on my first day, I could not help but notice five words written on big colorful boards: humble, thoughtful, bold, optimistic, and relentless. These represented the company’s values and I have to admit the first time I read them, I was confused. Of course, I knew what the words meant individually, but ...

Scaling StatsD

Overview Monitoring is hugely important, especially for a site like DoorDash that operates 24/7. In modern-day DevOps, monitoring allows us to be responsive to issues and helps us maintain reliable services. At DoorDash, we use StatsD heavily for custom metrics monitoring. In this blog post, we take a deeper look at how DoorDash uses StatsD ...

Avoiding Cache Stampede at DoorDash

One of the core mottoes on the engineering team at DoorDash is: We are only as good as our next delivery! With high traffic loads and orders flying in, every engineering decision has a critical impact on what our customers, merchants, and dashers will experience. We have to pay careful attention to the details and ...

How Artificial Intelligence Powers Logistics at DoorDash

In May, DoorDash participated at the O’Reilly Artificial Intelligence Conference in New York where I presented on “How DoorDash leverages AI in its logistics engine.” In this post, I walk you through the core logistics problem at DoorDash and describe how we use Artificial Intelligence (AI) in our logistics engine. LAST-MILE LOGISTICS IN A THREE-SIDED ...

Synchronizing Network Calls With RxJava

By Rohan Shanbhag and Wei Lin, Software Engineers Most Android apps rely on network calls to a set of backend services. As an app grows, so does the complexity of network calls and data operations. Networking libraries like Retrofit and Volley provide all the functionality needed for basic API calls. However, for threading and sequencing of events beyond a ...

Personalized Store Feed with Vector Embeddings

Customers come to DoorDash to discover and order from a vast selection of their favorite stores, so it is important to be able to surface what is most relevant to them. In a previous article, Powering Search & Recommendations at DoorDash, we discussed how we built our initial personalized search and discovery experience to surface the ...

Switchback Tests and Randomized Experimentation Under Network Effects at DoorDash

To A/B or not to A/B, that is the question Overview On the Dispatch team at DoorDash, we use simulation, empirical observation, and experimentation to make progress towards our goals; however, given the systemic nature of many of our products, simple A/B tests are often ineffective due to network effects. To be able to experiment ...

How we Designed Road Distances in DoorDash Search

By Richard Hwang and Aamir Manasawala, Software Engineers One of our goals at DoorDash is to surface to consumers a wide range of stores that are quickly deliverable to their given address. This process involves calculating accurate road distances for each store-consumer pair in our real-time search pipeline. Our earlier blog post about recommendations for search primarily ...