Topology

Queue Tools ▸ View Topology renders a read-only diagram of how the selected queue is wired into your messaging architecture:

• Producers — SNS topics with permission to publish to the queue, shown with "publishes via SNS subscription" edges.
• The queue itself — center node with its type (Standard/FIFO), depth, visibility timeout, retention, and encryption (KMS, SSE-SQS, or Unencrypted), plus a warning chip when the queue serves as a DLQ target.
• Dead-letter sources — queues whose redrive policy points at this queue (i.e., the queues this DLQ collects failures from).
• Redrive target — the DLQ this queue dead-letters to, with a Max receives N chip showing the receive-count threshold from the redrive policy.

The detail strip offers one-click copies of the queue ARN and URL, and the title bar links straight to the queue in the AWS Console.

How the Diagram Is Built

Topology is inferred from queue attributes, not from a separate discovery service:

• SNS producers are parsed from the queue's access policy — statements granting sns.amazonaws.com with a source-ARN condition. This is how SNS subscriptions manifest on the queue side, so it works with SQS permissions alone (no SNS API access required).
• DLQ relationships are parsed from redrive policies, cross-referenced against the queues loaded in your current region view.

That design has honest limits worth knowing:

• Lambda triggers and direct SDK producers don't appear. Event-source mappings live in Lambda's control plane, and plain SendMessage callers leave no trace on the queue. Absence of producers in the diagram doesn't mean nothing writes to the queue.
• Dead-letter sources are found among the queues in your loaded list, so a source queue in another region (or filtered out of your view) won't be drawn — the redrive target comes straight from the policy and is always shown.
• If some attribute lookups fail mid-render (e.g. missing GetQueueAttributes permission on a related queue), Tarmac shows a warning and falls back to what it already knows rather than failing the whole diagram.