Terraform Variable Validator

It parses your variables.tf file and checks for missing descriptions, missing type constraints, secrets that should be marked sensitive, type/default value mismatches (e.g. a number type with a string default), required variables without defaults, and tab characters that aren't valid HCL.

Type constraints tell Terraform what kind of value a variable expects: string, number, bool, list(string), map(string), set(string), object({...}), or tuple([...]). Without a type, Terraform infers any type, which can lead to unexpected behavior when a caller passes the wrong value type.

Marking a variable sensitive = true tells Terraform to redact its value from plan output, apply output, and state display. Without it, passwords, tokens, and API keys may appear in CI/CD logs or terraform show output in plain text.

A Terraform variable without a default value is required — callers must supply it via tfvars, environment variables (TF_VAR_name), or -var flags. A variable with a default is optional. Required variables are not necessarily secrets; they're just configuration that must be explicitly set per environment.

Not necessarily. Validation blocks are most useful for variables with a constrained set of valid values (e.g. environment = 'prod' | 'staging' | 'dev') or numeric ranges (e.g. instance_count between 1 and 10). For simple strings or flags, type constraints are usually sufficient.

No. All validation runs entirely in your browser using JavaScript. Your variables.tf content never leaves your machine.