[armon]

We use HCL broadly across the HashiCorp portfolio. It was popularized by Terraform, but also used in Vault, Consul, Nomad, and Packer.

Important to note, that HCL is designed to be completely interoperable with JSON. In practice, we find that HCL tends to be more human readable and writable and is significantly less verbose.

However, if you are doing any sort of machine generation, it can be convenient to generate JSON and feed that in.