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Identifying Non-Heap Class Leaks

April 18, 2016

At Wealthfront, a significant portion of our backend applications are written in Java. The Java Virtual Machine (JVM) uses Garbage Collection (GC) for memory management, this forces us to pay close attention to its characteristics and behavior. Every JVM service we run accumulates JVM and application-level statistics, spools these metrics into a statsd server, and… Read more

Building Mobile A/B Testing Infrastructure

April 11, 2016

Twenty years ago, one would have hardly heard the phrase “A/B testing”. In 2000, Google served its first A/B test to determine the optimal number of search results to display. In 2011 alone, they ran 7000 A/B tests across their platforms. A/B testing has become the bread and butter of product decision-making for Silicon Valley… Read more

Build System Integration Testing with Chef

April 05, 2016

At Wealthfront, we’re constantly pushing to use cutting edge technologies to take advantage of new language features, improved compilers, new libraries, and the like. Downtime in our build system would be a big problem with how often we like pushing new code to production, so we want a process that would allow us to upgrade parts… Read more

3 Ways to Integrate Third-Party Metrics into Your Data Platform

November 24, 2015

From both a company and engineering standpoint, Wealthfront values making decisions backed by quantitative methods. As noted in our previous blog post, Statistics is Eating the World, the key to enabling decisions backed by data is to build a platform that is automated and can scale across all aspects of our business. One of the… Read more

How We Avoid A/B Testing Errors with Shrinkage

October 29, 2015

At Wealthfront, we use A/B tests to make our services more effective, informative, and convenient. Each A/B test consists of two or more variants of a feature or design, which we expose to visitors at random until we have have enough data to infer which is better. In a previous post, we explained why we… Read more

Testing JavaScript Modules

October 13, 2015

In our previous post we outlined benefits of writing JavaScript in modules. One benefit we didn’t mention was how much more testable JavaScript modules are. In your test file you can require the module under test and let the require system import any dependencies. The goal of this post is to outline some of the… Read more