Specifically, neither YAML nor JSON are configuration formats (despite everyone's desire to use them as such). TOML is a very good generalization of a simple,

Specifically, neither YAML nor JSON are configuration formats (despite everyone's desire to use them as such). TOML is a very good generalization of a simple, straightforward configuration file format which was the "best" until TOML came around. If a service you are using needs JSON/YAML, you can generate it. But, stick with a configuration file format that is suitable for humans for actual configuration. Also, PSA, neither JSON nor YAML files are good places to embed logic. Also, another PSA, the fact that Pipfile is just a TOML file is just silly. Another point in Ruby's favor.