What is the primary language used to write Terraform configurations?

The primary language used to write Terraform configurations is HashiCorp Configuration Language (HCL). HCL is designed specifically for configuring infrastructure as code and is optimized for readability and usability, making it easier for users to define resources and their properties.

HCL provides a concise syntax that allows users to express complex infrastructure requirements in a clear and understandable manner. For example, it includes features like simple block structures and variable interpolation, which are tailored to the needs of defining infrastructure. Additionally, HCL is inherently compatible with Terraform's workflow, providing seamless integration into the tooling and enabling users to leverage its full capabilities.

While JSON can also be used for Terraform configurations, it is less common due to its verbosity and complexity compared to HCL. JSON is often more difficult for users to read and maintain, especially as configurations become larger and more complex. Thus, while it is technically possible to use JSON, HCL is preferred for its clarity and ease of use.