Guides
What Is HCL in Terraform?
HCL stands for HashiCorp Configuration Language, and it is the format Terraform uses for most human-written configuration. It is designed to be more readable than raw JSON while still being structured enough for infrastructure as code workflows.
Published March 22, 2026 · Updated March 22, 2026
Why Terraform Uses HCL
Terraform uses HCL because it gives teams a readable way to describe infrastructure, variables, and settings without forcing them into a more rigid machine-oriented format. It is practical for humans to edit while still being structured enough for tooling.
That is why many Terraform users think in HCL first, even when they still move data through JSON, YAML, or generated configuration values elsewhere in the workflow.
How HCL Relates To JSON And YAML
HCL, JSON, and YAML can represent similar configuration values, but they are used differently. JSON is common for APIs and machine data, YAML is common for general configuration and manifests, and HCL is more tightly associated with Terraform and HashiCorp-style workflows.
Converters become useful when you want to inspect Terraform-style input as JSON, or when you want to move JSON or YAML values into terraform.tfvars-style HCL assignments.
When HCL Conversion Tools Help
HCL conversion tools help when you need to inspect Terraform-style configuration more easily, review values in JSON, or turn structured JSON or YAML into readable HCL assignments.
They are especially useful when different parts of a workflow use different formats, but the underlying values still need to stay aligned.