> ## Documentation Index
> Fetch the complete documentation index at: https://firmngin.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# JavaScript Library

> Node.js integration notes for tools, gateways, and simulators

Use the JavaScript library for Node.js tools, simulators, gateways, and service integrations that need to interact with firmngin device or platform APIs.

## Use this library for

* Device simulators.
* Gateway processes that bridge non-MQTT devices.
* Internal tools that read device state.
* Automation helpers that need API access.

## Security note

Do not ship backend API tokens to browser code. Browser UI should call the firmngin backend through authenticated user sessions, not through service tokens embedded in JavaScript bundles.

## Basic client setup

\[code:create JavaScript client with base URL and token, then list devices]

## Standard errors

\[code:handle standard API error fields error and message]

Always prefer the standard `error` and `message` fields when displaying API errors.