I think any single feature isn't too difficult to replace with go's stdlib stuff. e.g. to read a flag, or read in a config file. Viper has sophisticated functi

I think any single feature isn't too difficult to replace with go's stdlib stuff. e.g. to read a flag, or read in a config file. Viper has sophisticated functionality such that it might read a config file from one of several paths; the properties of which can be overridden with environment variables or command line flags. With an emphasis on productivity, I think those mechanisms are useful, and probably not worth spending time to NIH from stdlib.