I'll answer my own question (after doing some research).
Besides the other answers, I found Cloudfare Workers[1] seem to nearly fit the bill (the only problem is that workers are written in JS - though you can also write them in Rust, C or C++, with the caveat that they compile to WASM, then are executed via the JS API).
Pricing start free! With $5/month you get access to KV (Key-Value Storage) and a generous amount of requests (10 million/month) which seems appropriate for my needs... and it's still in beta, but they also have consistent storage now with Durable Objects[2].
Besides the other answers, I found Cloudfare Workers[1] seem to nearly fit the bill (the only problem is that workers are written in JS - though you can also write them in Rust, C or C++, with the caveat that they compile to WASM, then are executed via the JS API).
Pricing start free! With $5/month you get access to KV (Key-Value Storage) and a generous amount of requests (10 million/month) which seems appropriate for my needs... and it's still in beta, but they also have consistent storage now with Durable Objects[2].
[1] https://developers.cloudflare.com/workers/tutorials
[2] https://developers.cloudflare.com/workers/learning/using-dur...