# Inputs

Input nodes define how data enters your StackAI workflow — from user messages and uploaded files to scheduled triggers and external form submissions.

Every workflow starts with at least one input node. Choose the type that matches how your agent receives data.

### In this section

<table data-view="cards"><thead><tr><th>Topic</th><th data-card-target data-type="content-ref">Page</th></tr></thead><tbody><tr><td><strong>Input Node</strong><br>Accept text, structured data, or user messages from the interface or API.</td><td><a href="inputs/input-node">input-node</a></td></tr><tr><td><strong>Files Node</strong><br>Accept uploaded files — PDFs, spreadsheets, images — as workflow inputs.</td><td><a href="inputs/files-node">files-node</a></td></tr><tr><td><strong>URL Input Node</strong><br>Fetch and use web page content as a workflow input.</td><td><a href="inputs/url-input-node">url-input-node</a></td></tr><tr><td><strong>Audio Input Node</strong><br>Accept audio files for transcription or analysis.</td><td><a href="inputs/audio-input-node">audio-input-node</a></td></tr><tr><td><strong>Trigger Node</strong><br>Start a workflow automatically on a schedule or external event.</td><td><a href="inputs/trigger-node">trigger-node</a></td></tr></tbody></table>

### Pick the right input for your use case

* Chat or API interface? Use the [**Input Node**](https://docs.stackai.com/workflow-builder/inputs/input-node).
* Handling uploaded documents? Use the [**Files Node**](https://docs.stackai.com/workflow-builder/inputs/files-node).
* Scheduled or event-driven jobs? Use the [**Trigger Node**](https://docs.stackai.com/workflow-builder/inputs/trigger-node).
* Working with audio? Use the [**Audio Input Node**](https://docs.stackai.com/workflow-builder/inputs/audio-input-node)**.**