How to fix Error: Extraneous JSON object property in Terraform

The error clearly states which property is extraneous and in which resource or block. Example:

`Error: Extraneous JSON object property
on main.tf.json line 5, in resource "aws_instance" "example":
5: "instance_label": "my-server"

No argument or block type is named 'instance_label'.`

Note the exact property name that's problematic.

Search the provider documentation (e.g., https://registry.terraform.io/providers/hashicorp/aws/) for the resource type mentioned in the error. Find the exact argument name in the documentation.

For example, for aws_instance, you might find the argument is actually instance_initiated_shutdown_behavior not instance_label.

Update your .tf.json file with the correct property name from the documentation:

Wrong:

{
  "resource": {
    "aws_instance": {
      "example": {
        "instance_label": "my-server"
      }
    }
  }
}

Correct:

{
  "resource": {
    "aws_instance": {
      "example": {
        "tags": {
          "Name": "my-server"
        }
      }
    }
  }
}

Check that the property is valid for the specific resource type. The same property name might exist for aws_instance but not aws_security_group. Use the provider's registry documentation specific to that resource.

For blocks like variable, valid arguments are only: type, default, and description. Any other property (like label, name, or required) will cause this error.

Terraform JSON uses snake_case for property names. Make sure you're not using camelCase or other conventions:

Wrong (camelCase):

{ "instanceType": "t2.micro" }

Correct (snake_case):

{ "instance_type": "t2.micro" }

After fixing the property name, validate your configuration:

terraform validate

If validation passes, your JSON configuration is now correct.

If you have many JSON configuration files, consider converting to HCL (.tf files) instead. HCL is more readable and is Terraform's native language:

terraform show -json yourstate.tfstate > state.json
terraform import -config=... # if needed

Alternatively, use jsonencode() in HCL when you need JSON: policy = jsonencode({...})