I want to start with - this is incredibly lean, and is super impressive to see such an extensive breakdown. I think that even the most savvy and frugal people would struggle to make large savings here.

A few thoughts/ideas still - have you asked Sentry [0] or Grafana (no link) for support? They might front you higher tiers of your current offerings for $0. AWS [1] also published a while back that they provide free credits for OSS projects, and in my experience they're generous and want to help. I don't know if they're still offering this though. My experience with AWS was that along with the credits came a healthy amount of Support and advice on ways to do things. These were often more expensive than the naive way of doing things in the name of redundancy. But given you're already all-in on AWS it seems like it might be no harm. If you were open to not being all-in on AWS, I've only got great things to say about pairing cloudfront offerings with AWS, but again yuo're talking minor savings for large amounts of work and complexity.

The obvious one is the EC2 instances for the actual compilation. Have you considered a hybrid model with always-on instances for even 30% of your linux capacity? A handwavy number we came up with at $PREV_PROJ was that it was cheaper to pre-allocate about 70% capacity on bare metal machines (with OVH and the likes), and burst for the last 30%.

[0] https://sentry.io/for/open-source/ [1] https://aws.amazon.com/blogs/opensource/aws-promotional-cred...