AWS provides Nextdoor with a high-performance website platform so customers can connect with their neighbors reliably and effortlessly. “We use Amazon CloudWatch to monitor our load balancers to ensure they are serving the right kinds of requests to our users,” says Wise. The company has also improved website performance by transitioning to Amazon EC2 C3 instances. “When we upgraded to Amazon EC2 C3, we were able to drop user-perceived site latency by 50 percent by doing nothing but changing our instance types,” says Wise. “And that actually helped drop our server costs by 20 percent. Very rarely do you get the opportunity to click one button, save money, and immediately improve user performance without any engineering effort at all. That’s what we can do using AWS.”

The company now has the reliable back-end technology it needs. “We have launched 50,000 servers in AWS over the past four years, says Wise. “We can do that because AWS provides a very reliable, robust API, so we can easily scale our site and quickly launch new virtual machines as we continue to grow. Knowing we can request a new machine, and moments later that machine will launch, has enabled us to do things like full software deployments using complete server farms with new machines. For example, if we do a new software release today, we’re able to launch 65 machines. It’s just automatic.”

That flexibility also helps Nextdoor developers move more quickly when they need to create new site features. “We can launch a complete test environment for an engineer in less than two hours,” says Wise. “With the click of a button, that person can have a segregated test environment, knowing that other teams won’t be impacted.”

Additionally, Nextdoor is using AWS to speed up server rollbacks during code releases in cases when the code isn’t working properly. “We direct all user traffic through AWS Elastic Load Balancing, and when we see things aren’t working the way we thought, the old machines are still there, and we can click a button to redirect traffic from the newer machines back to the older ones we know are good,” says Wise. “The operation takes place across seven load balancers and dozens of server instances, but it’s asynchronous, which means it can be completed in less than a minute.”

Nextdoor has added a layer of security with its Amazon VPC deployments. “We run 18 VPCs across three regions. From a management viewpoint, they act as one, but each VPC is isolated from the other VPCs,” says Wise. “Being able to manage machines behind these private networks gives us a high level of security.”

The company is also using its data analytics capabilities to improve the Nextdoor site for customers. “With the data that we get through Amazon Redshift, we can better understand where our members are going on the site and how they’re using the service,” says Wise. “That enables us to better track data growth without our production data stores, so we can forecast user growth milestones and track customer engagement metrics. This is how we find out what is important to our members so we can ultimately improve their experience. At the end of the day, that’s what we’re all about.”