Inspired by this reddit post.
This website plots every team in the MLB's bullpen era against their rotation era. Teams closer to the origin have better pitching.
This project was made using the MERN stack - MongoDB, Express.js, React.js, Node.js. It also incorporates a Python script that scrapes baseball-reference.com for the necessary data to create the chart. The charting library used is recharts.
The initial script for scraping (back to 1970) is included, as well as a daily script that is run every 24h to keep the current season up-to-date. This script is only live between the months of March and November due to baseball's off-season.
Selecting an individual team will graph that team's pitchers and their respective ERAs, color coded based on whether they are a starter or a reliever. Starter/reliever data is based solely on the data from baseball-reference.com - oftentimes a starter who has just been moved to the reliever role will not be updated as such until his 4th or 5th appearance as a reliever.
Team logos are stored as a url as scraped from baseball-reference.