See it as a diagram
Everything below, as a diagram you can edit. Describe yours and see it in seconds.
No account needed · Editable canvas, not a picture
What Rover is good at
The plan is the point. Rover generates a plan file or takes a pre-generated plan JSON, then renders what a run will do alongside the structure it will act on. For reviewing a change before applying it, that is exactly the right frame, and the interactive UI beats reading plan output in a terminal.
The details are well judged: modules, count usage, outputs, and locals are all visible rather than flattened away, a Docker image saves the local setup, backend config and variable files can be passed in with flags, -standalone true packages the static assets into a rover.zip, and -genImage true writes an SVG when what you need is a file rather than a server on port 9000.
It is actively maintained and free, and for the job it was built for there is not much competition.
Three limits that matter for documentation
Generating a plan is not free. It means a Terraform binary, an initialized working directory, backend access, variable files, and often credentials in the environment, which is a heavier requirement than reading source and one many repositories cannot satisfy from a laptop or a shared runner. Passing a pre-generated plan with -planJSONPath does not remove the requirement, it moves it to whoever produced the plan, and a plan JSON is a sensitive artifact in its own right.
The output is local. A web app on localhost is for the person who ran it. Sharing means the standalone zip or an exported image, which puts you back in the business of regenerating and re-sending artifacts every time infrastructure changes.
And the shape is plan-shaped. A dependency graph answers what depends on what, which is a debugging question. The architecture question, what does this platform consist of and how does it fit together, wants module boundaries, curated importance, and provider icons rather than a complete edge set.
The source parse, hosted and scheduled
Datadef parses the .tf and .tfvars files of a connected repository directly. No init, no plan, no state, no cloud credentials, just a read-only token on GitHub, GitLab, or Azure DevOps and a branch or tag. That is what makes it usable against a production repository or a client repository you can only read.
The drawing is curated before it is rendered, and the curation is deterministic rather than a matter of taste. Modules become zones, no zone holds more than eight nodes, major resources keep their provider icons, and a repeated minor type inside a module rolls up into one node carrying the count and the member names, as in Storage credentials ×2: external, root. Anything left over folds into a single Supporting resources node with its count. The platform repository this was tuned against holds 123 declared resources and reads at around 36 nodes, with the full inventory kept in a generated module reference table.
What never becomes a box is as deliberate. Role assignments, IAM policies, grants, permissions, secrets, diagnostic settings, and every resource from the random, null, tls, and time providers are classified as wiring and counted in a note instead. Node ids come from the Terraform address rather than from the model, so azurerm_storage_account.lake inside module.data is the same node tomorrow that it was today, and a node someone dragged is put back where they left it: the sync records the layout it wrote, and anything more than 12 pixels away from that counts as hand-placed.
Then it stays current on its own: a daily sync, on-demand refresh, and MCP tools so a coding agent can trigger a re-sync after a change merges. The diagram embeds in a README or wiki as a live image, which is the part a localhost UI cannot do. More on the pipeline in visualize a Terraform repository.
Use both, for different questions
Keep Rover for plan review. Before an apply, seeing what will change and how it connects to what exists is a debugging need with a local answer, and Datadef does not do plan diffs.
Use a synced diagram for the questions that outlive the terminal session: onboarding, incident response, security review, and the architecture page someone opens six months from now expecting it to be true.
FAQ
Does Datadef run terraform plan?
Can it show what a change will do, like a plan visualization?
How is the result shared with people who do not run Terraform?
Are modules, counts, and for_each handled?
Does the diagram get reshuffled every time it regenerates?