I once got a job for a company whose entire stack was aws lambda. Not like a normal 'hey we have this flask application which handles 100 endpoints and we just use lambda to handle a call' - more like 'every singe route or function is its own lambda function'. I left inside 2 weeks.
Saw this with an infamous 996 AI startup where the founders vibe coded their app.
Their app had like 3 or 4 pages, that was all, but every endpoint was a Lambda call. Every frontend log entry was a Lambda call. Every job execution was a Lambda call that called a dozen others. That was their idea of an architecture.
Even with <100 customers they were already paying >100k dollars a month on cloud, more than their entire dev team cost.
The constant firefighting, downtimes and billing issues were enough to keep the team busy instead of making new features.
I was freelancing but I didn't take the job after the "CTO" gave me a tour.
In principle, serverless should be very efficient and cheap if all code is running the same VM. The heterogeneous architecture must make it expensive. Maybe serverless using WASM will one day make it cheap.
