Application Services 3 Extension Documentation

Welcome to the F5 Application Services 3 Extension User Guide. This the documentation for the latest version of AS3, if you want to see the documentation for a long term support (LTS) version, use the version selector on the top left (for details, see Support information on GitHub).

To provide feedback on this documentation, you can file a GitHub Issue, or email us at


To see what’s new in AS3, see the the Document Revision History or the Release Notes on GitHub.


Application Services 3 Extension (referred to as AS3 Extension or more often simply AS3) is a flexible, low-overhead mechanism for managing application-specific configurations on a BIG-IP system. AS3 uses a declarative model, meaning you provide a JSON declaration rather than a set of imperative commands. The declaration represents the configuration which AS3 is responsible for creating on a BIG-IP system. AS3 is well-defined according to the rules of JSON Schema, and declarations validate according to JSON Schema. AS3 accepts declaration updates via REST (push), reference (pull), or CLI (flat file editing).

You can use Microsoft Visual Studio Code to validate your declarations, see Validating a Declaration for information.

This guide contains information on downloading, installing, and using the Application Services 3 Extension.

You can also see our AS3 overview video:

And the Using AS3 video:

Use the following links, the navigation on the left, and/or the Next and Previous buttons to explore the documentation.