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

# Develop with client APIs

For application developers on the application processor. The Qualcomm® sensing hub (QSH) client APIs provide a C++ interface that enables Linux applications to access sensor data from the QSH framework running on the low-power processor. Before writing code, see [Data Model](./sensor_api_messages) to understand the request and event message format.

<CardGroup cols={2}>
  <Card title="QSH client API workflow" href="./qsh_client_apis">
    The session lifecycle for client applications: `getSession()`, `open()`, `close()`, `setCallback()`, and `sendRequest()`. Start here before building any sensor application.
  </Card>

  <Card title="Develop applications using the QSH client APIs" href="./develop_app">
    Walk through the `SessionClient` sample application. Covers SUID query, attribute query, and streaming call flow with annotated architecture diagrams.
  </Card>

  <Card title="Configure sensors" href="./calibrate">
    Configure sensors using registry files and calibration procedures for the QCS6490 platform.
  </Card>
</CardGroup>