Workflows SDK

Workflows SDK

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What is Vellum Workflows SDK?

The Vellum Workflows SDK is a framework for defining and executing agentic AI systems as graphs using a declarative, type-safe approach. Unlike other graph frameworks that are functional or event-driven, Vellum Workflows SDK:

  • Defines control flow statically and declaratively with strict typing
  • Provides type safety and intellisense benefits
  • Makes graph structure known ahead of time
  • Creates more predictable and robust AI systems

Additionally, Vellum Workflows SDK provides bidirectional syncing between code and Vellum’s visual editor, making it easier to:

  • Visualize and debug complex graphs (with loops, conditionals, and other control flow)
  • Edit graphs visually or in code
  • Execute graphs directly from the UI
  • Seamlessly sync changes between code and UI
  • Collaborate with non-technical users more directly

Open Source

The Vellum Workflows SDK is fully open source and publicly available on GitHub.

Core Features

FeatureDescription
UI IntegrationBidirectional syncing between code and Vellum’s visual editor
NodesThe basic building blocks of a graph that represent single tasks or functions
Graph SyntaxIntuitive, declarative syntax for defining graph control flow
Inputs/OutputsPass information between Nodes or Workflows using typed inputs and outputs
State ManagementShare information between Nodes through the graph’s global state
Advanced Control FlowSupport for loops, conditionals, parallelism, state forking, and more
StreamingReturn partial results from long-running tasks like chat completions
Human-in-the-loopPause Workflows for human or external system input

How It Works

  1. Define Nodes: Create reusable components that represent specific tasks

  2. Build Your Graph: Connect nodes to define your workflow’s execution path

  3. Configure I/O: Set up inputs, outputs, and state management for data flow

  4. Execute: Run your workflow either programmatically or through the UI

  5. Visualize & Debug: Use the UI to inspect execution paths and results

Getting Started

Code-first Quickstart

Define a Workflow entirely in code with full type safety, then push to UI

UI-first Quickstart

Build visually in the UI, then pull changes into code

Core Concepts

Learn about the core concepts of Vellum Workflows SDK