Based on our record, Google Cloud Monitoring API seems to be more popular. It has been mentiond 1 time since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I don't think there is straightforward way of getting usage data from firebase apis, but you can get what you want via Google Cloud Monitoring API. Source: almost 2 years ago
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
BounceX - BounceX's Behavioral Marketing Cloud offers a full-service suite of behavioral marketing solutions.
Conversant - Conversant provides online advertising campaigns and programs for advertisers and advertising agency customers.
Better Uptime - We call you when your website goes down
Site24x7 - Site24x7 offers both free & paid website monitoring services. Monitor websites remotely and receive instant email/sms alerts if your website becomes unavailable. View uptime & performance graphs of your website monitors.