Durable Viz

Visualize AWS Lambda Durable Functions workflows directly in VS Code. Static analysis turns your handler code into an interactive flowchart, no deployment or execution required.

Supports TypeScript/JavaScript, Python, and Java runtimes.

Features

Interactive diagram. See your durable function as a flowchart in a side panel.
Scroll zoom. Scroll wheel to zoom in/out, zooms toward cursor.
Click-drag pan. Click and drag to move around the diagram.
Click-to-navigate. Click any node to jump to that line in the source file.
Auto-refresh. Diagram updates when you save the file.
Direction toggle. Switch between top-down (TD) and left-right (LR) layout.
Save PNG. Export the diagram as a high-resolution transparent PNG.
Source view. View the raw Mermaid syntax or JSON graph.
All primitives. Step, invoke, parallel, map, wait, callbacks, conditions, child contexts.

Usage

Open a file containing a durable function handler.
Open the command palette (Ctrl+Shift+P / Cmd+Shift+P).
Run Durable Viz: Open Lambda Durable Function Workflow.

The diagram appears in a side panel next to your code. A toolbar button also appears in the editor title bar for supported file types.

Supported Languages

Language	Handler detection	SDK
TypeScript / JavaScript	`withDurableExecution()`	`@aws/durable-execution-sdk-js`
Python	`@durable_execution` decorator	`aws-durable-execution-sdk-python`
Java	`extends DurableHandler`	`aws-durable-execution-sdk-java`

Detected Primitives

Java SDK support is in preview with some primitives still in development.

Primitive	TypeScript	Python	Java (preview)
Step	`context.step()`	`context.step()`	`ctx.step()`
Invoke	`context.invoke()`	`context.invoke()`	`ctx.invoke()`
Parallel	`context.parallel()`	`context.parallel()`	in development
Map	`context.map()`	`context.map()`	in development
Wait	`context.wait()`	`context.wait()`	`ctx.wait()`
Wait for Callback	`context.waitForCallback()`	`context.wait_for_callback()`	in development
Create Callback	`context.createCallback()`	`context.create_callback()`	`ctx.createCallback()`
Wait for Condition	`context.waitForCondition()`	`context.wait_for_condition()`	in development
Child Context	`context.runInChildContext()`	`context.run_in_child_context()`	`ctx.runInChildContext()`

Visual Encoding

Each primitive type has a distinct shape and color:

Node	Shape	Color
Start / End	Stadium	Blue
Step	Rectangle	Green
Invoke	Trapezoid	Amber
Parallel / Map	Hexagon	Purple
Wait / Callback	Circle	Red
Condition	Diamond	Indigo
Child Context	Subroutine	Teal

Parallel branches are grouped inside a dashed border. Conditional branches show "yes" and "no" edges.

CLI

This extension is part of durable-viz, which also includes a CLI:

npx durable-viz handler.ts --open

License

MIT

Durable Viz

Gunnar Grosch

Durable Viz

Features

Usage

Supported Languages

Detected Primitives

Visual Encoding

CLI

Links

License