When you replace or significantly modify components of a larger system, too frequently we focus on whether the code we are building functions correctly. This is important, but it’s also short-sighted. It’s easy to introduce errors because we are changing interactions. Coding bugs are only one quality problem.

A feature flag is a configuration setting that lets you turn a given feature on or off. There is no need for a feature to be complete before you can start testing—as soon as the first piece of code is merged, you can turn the flag on in your test environment and begin. This also reduces risk. Do you use feature flags?

Hijacking accounts is one of the top online security threats, with billions of usernames and passwords from different platforms available on black markets. To understand how hijackers steal passwords and other sensitive data, Google partnered with UC Berkeley in a study of Google accounts.