The Terraform Drift Detection Helper compares the resource addresses in your pasted Terraform configuration against those in a pasted .tfstate JSON, and lists the differences. It surfaces resources that exist in your code but not yet in state, and resources that exist in state but are absent from your current configuration, which are often orphaned infrastructure.
This is a local, client-side comparison of addresses only; it does not connect to a cloud and it does not compute real drift, which requires running terraform plan against live infrastructure. What it does provide is a fast, private first pass: confirm that what you intend to manage matches what Terraform already tracks, before you run a plan. Everything runs in your browser, so nothing is uploaded and no credentials are needed. It is useful for cleaning up deleted resources, finding orphaned state entries, and building a report you can attach to a review.
A key thing to understand is the boundary of this tool. It compares addresses, not attribute values, and it never calls a provider, so it cannot tell you that an aws_instance size was changed out of band. For that deeper check you still need terraform plan. But the address comparison catches the most common housekeeping problems: code that was written but never applied, and state that references resources nobody maintains anymore. Those are exactly the issues that accumulate silently over months of day to day work.
Used as a pre-plan step, the helper keeps your state tidy. Run it after refactoring modules or deleting resources by hand, and the orphan list will show what terraform destroy still needs to clean up. That small habit prevents surprise charges and keeps the state file honest about what really exists.