"just make everything a protobuf" (or whichever system you prefer). The config file is essentially an API and APIs really benefit when they're typed. You can

"just make everything a protobuf" (or whichever system you prefer). The config file is essentially an API and APIs really benefit when they're typed. You can make a actual API to expose application configuration knobs too which is nice but you should tie this into your rollout/CICD system so you're just as careful pushing new configuration values as you are when pushing new binaries (multiple envs, slow rollouts, blue/green etc).