---
title: "Concepts"
description: "What a workflow is, how a graph is wired, and the JSON the editor and your backend exchange."
source: https://flowdrop.io/docs/concepts
site: FlowDrop documentation
---
# Concepts
The vocabulary the rest of this documentation assumes, and the data model both
halves of FlowDrop agree on. None of it is specific to a backend.

<CardGroup cols={2}>
  <Card title="What is a workflow?" icon="diagram-project" href="/concepts/what-is-a-workflow">
    The mental model, and the contract between the editor and your backend.
  </Card>
  <Card title="Thinking in graphs" icon="boxes-stacked" href="/concepts/thinking-in-graphs">
    Grow a familiar shell command into a workflow graph.
  </Card>
  <Card title="Architecture overview" icon="layer-group" href="/concepts/architecture-overview">
    How the modules, components, stores and services fit together.
  </Card>
  <Card title="Port system" icon="plug" href="/concepts/port-system">
    Ports, data types, compatibility rules and gateway branches.
  </Card>
</CardGroup>

## The data model

A workflow is JSON. These pages are the format, field by field.

- [Workflow structure](/concepts/workflow-json) — the top-level document
- [Node structure](/concepts/node-json) — nodes, metadata and config values
- [Edge structure](/concepts/edge-json) — connections and handle IDs
- [Workflow interface](/concepts/workflow-interface) — a workflow's public inputs and outputs
- [Glossary](/concepts/glossary) — every term, defined once

The normative rules live in the
[FlowDrop Workflow Specification](https://flowdrop.io/spec/), which is a sibling of this site rather
than a section of it.