Fluent flow builder for TypeScript

Zero-dependency. Composable. Plugin-driven. Built for LLM pipelines and beyond.

Fluent & Composable

Chain steps with .startWith(), .then(), .branch(), .loop(), .batch(), and .parallel() — all through one FlowBuilder class.

Plugin System

Extend any flow with hooks registered via FlowBuilder.extend(). The stable surface stays focused on a smaller set of core plugins, with helpers available when you need them.

LLM-Native

First-class support for structured output validation, tool calling, ReAct agent loops, human-in-the-loop interrupts, and streaming token output.

Zero Dependencies

The core is pure TypeScript with no runtime dependencies. Plugins are tree-shaken so you only ship what you use.

Shared-State Model

Every step receives a single mutable shared object. No message-passing boilerplate — just read and write the state you need.

Graph Composition

Declare flows as DAGs with addNode/addEdge and let Flowneer compile them into efficient sequential or conditional pipelines.