Engineering

Insights from the Rainforest QA engineering team.

Surprise, your data warehouse can RAG
How to use your data warehouse's built-in features to simplify and potentially improve your RAG pipeline.
Building reliable systems out of unreliable agents
This is the process our engineering team uses to create reliable AI systems out of unreliable AI agents.
Three ways to draw pie charts without any JavaScript
In this post, we share three different approaches to drawing pie charts using only HTML and CSS.
The engineering hiring process at Rainforest QA
Here's the exact hiring process we use to evaluate candidates for the engineering team here at Rainforest QA.
Hunting a race condition in the Android 10 Emulator
How we found a race condition in the AOSP with the Android emulator that affected the amount of heap space available to apps. Rainforest supports testing native mobile applications on Android using the official android emulator from Google. Using emulators instead of real physical devices provides a bunch of benefits such as being able to […]
Discrete optimization for on-call scheduling
The engineering team of RainforestQA (YC S12) is remote and distributed around the globe, with developers in America, Europe, and Asia. We’re using PagerDuty to assign developers on-call and for contacting/escalating people in case of incidents. Our working hours cover almost all time-zones, about 22 hours from full time-zone coverage. Yet for distributing our on-call […]
A deep dive into macOS TCC.db
A deep dive into what the TCC database contains and the meaning of the various fields present in it. What is TCC? TCC (Transparency, Consent, and Control) is a mechanism in macOS to limit and control application access to certain features, usually from a privacy perspective. This can include things such as location services, contacts, […]
Selecting a finite state machine library for React
This article is going to look at different libraries providing finite state machine abstractions that can be used in React applications. I have used state machines on the backend in the past but I have never used one in a React application. I’m also going to share why I believe our codebase could benefit from […]
Upgrading our SaaS application to Rails 6
A sustainable Rails upgrade workflow that slowly but surely brought us to the point when all our apps run on latest Rails. Rainforest main application is a Rails monolith with 160k lines of code and tests. Bumping a major version of rails in a project this big has overwhelming results, in fact no rails command […]
Zero downtime database migrations
In this post we explain the basics of how to handle database migrations properly and show some real world examples. Learn how to achieve zero downtime database migrations.
How to remove Recompose and replace with Hooks
In our last post, we explored the pros and cons of Recompose and why we decided to remove it from our codebase. This post includes the strategy we used to approach the large task of implementing that refactor.
Why we decided to replace Recompose with React Hooks
We recently made the decision to remove Recompose entirely – which was a large endeavor. It touched over 200 files, and in some places was deeply coupled to core functionality of our app.This post covers why we decided to replace Recompose.
How and why we migrated from Heroku to Kubernetes
Here's how Rainforest QA made the decision to upgrade our DevOps teck stack and move from Heroku to Google Cloud Platform (GCP) and Google Kubernetes Engine (GKE).
How to Estimate a Software Project Timeline
In this post we explore how to develop a project timeline and some general best practices for smoother project management.