App Inspector
Introduction
Section titled “Introduction”App Inspector allows users to view, collect, and inspect data exchanges, including payloads and metadata, between AWS services. It enhances system observability by displaying the data exchanged at every stage, facilitating clear understanding of operation flows. In addition, it serves as a single point of truth to understand potential errors, service configuration mismatches, and IAM permission issues.
With App Inspector, you can:
- Observe and understand the flow of operations through your system.
- Identify errors and obtain detailed information for corrections.
- Get immediate feedback on any misconfigurations in your services.
- Gain insights into IAM policies and detect missing permissions.
Requirements
Section titled “Requirements”App Inspector requires LocalStack 2026.03.0 or later.
Use Cases
Section titled “Use Cases”Understanding service-to-service information flow
When a service call doesn’t reach its intended target, App Inspector shows exactly where it stopped and why — tracing the flow of information between services at every hop. You get a precise answer without deploying to AWS or adding instrumentation.
Verifying service-to-service payloads
Inspect the exact data passed between services at every hop of your workflow. For example, confirming that a Lambda is passing the right payload to SNS, or that an SQS message body matches what the downstream consumer expects — before it becomes a production issue.
Catching IAM misconfigurations early
App Inspector runs against the real LocalStack emulator, which enforces IAM policies. Missing or overly restrictive permissions show up immediately — in your local environment, where they’re fast and cheap to fix, rather than at deployment time in the cloud.
LocalStack Toolkit for VS Code
Section titled “LocalStack Toolkit for VS Code”App Inspector is built into the LocalStack Toolkit for VS Code, so you can trace operation flows and inspect payloads without leaving your editor. Once LocalStack is running, open the App Inspector panel directly in the LocalStack Toolkit extension to view operations and drill into service interactions.
If you haven’t set up the toolkit yet, see LocalStack Toolkit for VS Code to get started.
Web Application
Section titled “Web Application”You can access App Inspector directly in the LocalStack Web Application. Navigate to App Inspector in your browser to view operations captured from your running LocalStack instance, inspect payloads, and trace service connections.
Features
Section titled “Features”List Operations
Section titled “List Operations”You can view a detailed list of operations in your application, including the Producer (the service that initiated the call), Consumer (the target service), Action (the specific API call made), and Timestamp. Operations that encountered errors are flagged inline, so you can identify failures at a glance. Click View Graph on any operation to switch to the graph view and see how services connect.
The interface enables you to trace the flow of operations, identify relationships between services, and analyze patterns for debugging or optimization.
Graph View and Operation Details
Section titled “Graph View and Operation Details”Click View Graph to visualize the relationships between AWS services in your application as an interactive graph. Each node represents a service, and each edge represents a call between them, making it easy to follow the path of a request across your architecture.
By clicking on an operation in the graph or list, you can drill down into the specifics of each interaction. App Inspector displays detailed payloads, metadata, and status for each operation, and highlights errors, warnings, and potential IAM permission issues, enabling precise debugging and troubleshooting.
Plans & Tiers
Section titled “Plans & Tiers”| Feature | Hobby | Base / Ultimate / Enterprise |
|---|---|---|
| Maximum operations stored | 10 | 1,000 |
| Error analysis | — | ✓ |
| Request payload | ✓ | ✓ |
| Response payload | — | ✓ |
Supported Services
Section titled “Supported Services”All service operations appear in App Inspector. The following services have been optimized for improved visual layout in the graph view: