# Developer Tools - Overview

The developer tools page is split into two tabs:

  • Expert Features
  • Debugging Features: Test the SSE connection and test different implementations of an icon for different states.

# Expert Features

# Advanced Object Managment

  • Widgets
    Develop custom widgets, that can be then used on your pages. Community made widgets can be installed from the UI tab of the add-on store.
  • Block Libraries
    Even though Blockly comes with a large library of blocks out of the box, you can still extend it by developing your own Block libraries.
  • Add Items from textual definition
    Create or update Items and links in bulk by using the .items-file syntax.

# Maintenance Tools

  • Developer Sidebar
    The developer sidebar is accessible from anywhere in the UI and provides both an integrated help and developer tools, like the universal search or the widget expression tester. The integrated help even actually renders selected parts of the Main UI documentation. So if you read this from the website, you can also read this from inside the UI.
  • API Explorer
    Interactively discover and access the REST API, which is also used by Main UI to interact with the openHAB server.