> For the complete documentation index, see [llms.txt](https://docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verifone.com/adk-os-platform/readme/developing-applications.md).

# Developing Applications on VOS3

## Developing Applications on VOS3

VOS3 application development uses the VOS3 SDK, ADK APIs, toolchain, and `packman` to build, package, sign, load, and debug applications on Verifone devices.

Use this section to understand the full VOS3 developer workflow before you dive into setup, packaging, or debugging details.

### What you will do in this section

In this section, you will learn how to:

* set up a VOS3 development environment on your host PC
* prepare APP-DEV terminals for development and testing
* build applications against the VOS3 SDK and ADK APIs
* package, sign, load, and debug VOS3 applications

### Core VOS3 concepts

Before you start, keep these concepts in mind:

* **APP-DEV devices** are development terminals for testing, loading, and development signing.
* **VOS3 SDK and toolchain** provide the compiler, debugger, headers, libraries, and system files.
* **ADK APIs** provide the supported application interfaces and libraries for VOS3 development.
* **Packages, manifests, and DL files** define how applications are bundled and installed on devices.
* **Development signing and production signing** serve different stages of the release process.
* **Remote debugging** uses `gdb` on the host and `gdbserver` on the device.

### Recommended workflow

Follow this workflow for most VOS3 application projects:

{% stepper %}
{% step %}

### Set up your host environment

Install the VOS3 SDK, compiler toolchain, packaging tools, and your preferred IDE.

Start with Developer Setup.
{% endstep %}

{% step %}

### Prepare a development terminal

Use an APP-DEV device, connect the required cables, and enable console access when needed.

See [Preparing Development Devices](/adk-os-platform/readme/developing-applications/preparing-development-devices.md).
{% endstep %}

{% step %}

### Build your application

Compile against the VOS3 SDK and link only supported ADK and open source libraries.

See [Developing application](/adk-os-platform/readme/developing-applications/developing-application.md).
{% endstep %}

{% step %}

### Package and sign the application

Create a manifest, choose the right package types, and build a DL file with `packman`.

See [Packaging](/adk-os-platform/readme/developing-applications/packaging.md).
{% endstep %}

{% step %}

### Load, debug, and iterate

Run your application on device, start `gdbserver`, connect with `gdb`, and fix issues quickly.

See [Debugging applications](/adk-os-platform/readme/developing-applications/debugging-applications.md).
{% endstep %}
{% endstepper %}

### Pages in this section

Use these pages based on the task you are working on:

* [Developer Setup](/adk-os-platform/readme/developing-applications/developer-setup.md) — host PC requirements, Linux setup, tools, and IDE integration
* [Preparing Development Devices](/adk-os-platform/readme/developing-applications/preparing-development-devices.md) — APP-DEV devices, cabling, USB setup, and console access
* [Developing application](/adk-os-platform/readme/developing-applications/developing-application.md) — SDK contents, ADK libraries, compiler flags, linker flags, and build guidance
* [Packaging](/adk-os-platform/readme/developing-applications/packaging.md) — manifest structure, package types, signing, dependencies, and installation rules
* [Debugging applications](/adk-os-platform/readme/developing-applications/debugging-applications.md) — remote debugging with `gdb` and `gdbserver`
* [Windows development environment example](/adk-os-platform/readme/developing-applications/windows-development-environment-example.md) — example setup for Windows-based development

### Related guides

Use these guides when you need adjacent reference material:

* [Migration Guide from Previous Platforms](/adk-os-platform/readme/migration-guide.md) — migrate from earlier Verifone platforms to VOS3
* [Programmers Guides](broken://pages/hLb0K9HzU4f9GZkPgpvp) — choose the ADK version that matches your environment
* [ADK Release Notes](https://docs.verifone.com/adk-release-notes/) — version changes, fixes, and updates


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