durable-viz

Static analysis for AWS Lambda Durable Functions workflows. Parses handler code and renders an interactive flowchart — no deployment or execution required.

Supports TypeScript/JavaScript, Python, Java, and C# (.NET) runtimes.

Quick Start

npx durable-viz handler.ts --open

Opens an interactive diagram in your browser with scroll zoom, click-drag panning, direction toggle, source view, PNG export, and a dark theme.

Usage

Usage: durable-viz [options] <file>

Arguments:
  file                   Path to a durable function handler file

Options:
  -d, --direction <dir>  Graph direction: TD (top-down) or LR (left-right) (default: "TD")
  -n, --name <name>      Override the workflow name
  --json                 Output the raw workflow graph as JSON
  -o, --open             Open the diagram in your browser
  -V, --version          Output the version number
  -h, --help             Display help

Output Formats

Mermaid (default) prints Mermaid flowchart syntax to stdout. Paste into GitHub Markdown, Notion, or any Mermaid-compatible renderer.

durable-viz handler.ts

Browser generates a self-contained HTML file and opens it.

durable-viz handler.ts --open

JSON outputs the raw workflow graph for custom tooling.

durable-viz handler.ts --json

Supported Primitives

| Primitive | TypeScript | Python | Java | C# (.NET) | | --- | --- | --- | --- | --- | | Step | context.step() | context.step() | ctx.step() | ctx.StepAsync() | | Invoke | context.invoke() | context.invoke() | ctx.invoke() | ctx.InvokeAsync() | | Parallel | context.parallel() | context.parallel() | ctx.parallel() | ctx.ParallelAsync() | | Map | context.map() | context.map() | ctx.map() | ctx.MapAsync() | | Wait | context.wait() | context.wait() | ctx.wait() | ctx.WaitAsync() | | Wait for Callback | context.waitForCallback() | context.wait_for_callback() | ctx.waitForCallback() | ctx.WaitForCallbackAsync() | | Create Callback | context.createCallback() | context.create_callback() | ctx.createCallback() | ctx.CreateCallbackAsync() | | Wait for Condition | context.waitForCondition() | context.wait_for_condition() | ctx.waitForCondition() | ctx.WaitForConditionAsync() | | Child Context | context.runInChildContext() | context.run_in_child_context() | ctx.runInChildContext() | ctx.RunInChildContextAsync() | | With Retry | withRetry(context, ...) | with_retry(context, ...) | ctx.withRetry(...) | via StepConfig |

TypeScript also supports context.promise.all(), context.promise.any(), context.promise.race(), and context.promise.allSettled().

Java also supports DurableFuture.allOf(futures...) and DurableFuture.anyOf(futures...).

Visual Encoding

| 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 / With Retry | Subroutine | Teal |

Build Mode

For visual workflow design with code generation, use the VS Code extension and run Durable Viz: Build Workflow Diagram.

Links

• GitHub Repository
• AWS Lambda Durable Functions Documentation

License

MIT