Building for reliability at HelloSign
Filling out forms is stressful and boring, so people avoid it. If getting people to fill out forms is critical to your job or your business, you know what a big problem this is. HelloWorks is a HelloSign product that’s solving this problem through automating the process of converting PDF forms into an intelligent, mobile-friendly format that boosts accuracy and completion rates. Data collection is critically important both to the organization requesting the information as well as the person filling out the form. The end-to-end reliability of this process is one of its most important requirements, and one we’ve spent an incredible amount of time and effort on.
It’s the end of another chilly day as the setting sun turns the inhabitants of San Francisco into blind mice running through a maze. Meanwhile, another late night is slowly shifting to early morning, stuffed inside of a closet sized meeting room as we solve yet another gnarly technical challenge. Favoring speed over stability has led to increasing technical debt. After a couple months of dealing with the fallout, our engineering team took a step back to look holistically at why some unexpected behaviors were happening. We traced the overwhelming majority back to the application’s core. To fix this, we decided to bucket code into three tiers dubbed the error kernel, core features, and extended features.
An error kernel is the part of an application or system that should never fail. This is ideally as small as possible since the less surface area that it has, the less likely catastrophic failures will happen. When they do happen, the core system is small enough to reason about which greatly helps with triage and cauterizing of wounds.
