durable-viz

Visualize AWS Lambda Durable Functions workflows. Static analysis turns your handler code into a flowchart, no deployment or execution required.

Supports TypeScript/JavaScript, Python, and Java runtimes.

graph LR
  node_start([Start])
  step_1[validate]
  parallel_2{{prepare}}
  subgraph sub_parallel_2[" "]
    invoke_3[/check-inventory\]
    invoke_4[/reserve-payment\]
  end
  style sub_parallel_2 fill:transparent,stroke:#444,stroke-width:1px,stroke-dasharray:5 5
  step_5[fulfill]
  cond_6{approval?}
  callback_7((wait))
  node_end([End])
  node_start --> step_1
  step_1 --> parallel_2
  parallel_2 --> invoke_3
  parallel_2 --> invoke_4
  invoke_3 --> step_5
  invoke_4 --> step_5
  step_5 --> cond_6
  cond_6 -->|yes| callback_7
  cond_6 -->|no| node_end
  callback_7 --> node_end
  style node_start fill:#5b8ab4,stroke:#4a7293,color:#e8edf2
  style step_1 fill:#4a8c72,stroke:#3d7360,color:#e0efe8
  style parallel_2 fill:#7b6b9e,stroke:#655883,color:#e8e3f0
  style invoke_3 fill:#b8873a,stroke:#967032,color:#f5edd8
  style invoke_4 fill:#b8873a,stroke:#967032,color:#f5edd8
  style step_5 fill:#4a8c72,stroke:#3d7360,color:#e0efe8
  style cond_6 fill:#6b71a8,stroke:#575c8a,color:#e3e4f0
  style callback_7 fill:#b05a5a,stroke:#8f4a4a,color:#f2e0e0
  style node_end fill:#5b8ab4,stroke:#4a7293,color:#e8edf2

Quick Start

npx durable-viz handler.ts --open

This parses the handler, extracts the workflow structure, and opens an interactive diagram in your browser with scroll zoom, click-drag panning, direction toggle, source view, 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

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() |

VS Code Extension

Also available as a VS Code extension with an interactive side panel, click-to-navigate, and auto-refresh on save.

Install from VS Code Marketplace

Links

• GitHub Repository
• AWS Lambda Durable Functions Documentation

License

MIT