Checkly is a key part of a professional developer’s workflow, making it easy to know if your service is up or down, and measure performance. As we integrate with almost any development workflow, we also have Prometheus endpoints to let you use the popular Grafana stack to keep track of your site checks’ status. However, large enterprise users grew in usage, causing their check performance data to grow, resulting in occasional 429 status codes. To optimize this process, Checkly added compression at a surprising layer of its stack, specifically using the Brotli compression algorithm on Node.js. This was done after testing showed that Prometheus response metrics can be big and compressing them would significantly reduce storage space and improve performance. However, Heroku dynos struggled to run the compression, leading the team to find an optimal configuration by optimizing the compression parameters, finding a sweet spot between CPU usage and quality of compression. By doing so, they were able to deliver better performance to their users without increasing infrastructure costs.