# Delta Publish and Subscribe

Delta messaging in AMPS has two independent aspects:

* **Delta Subscribe** - Allows subscribers to receive just the fields that are updated within a message.
* **Delta Publish** - Allows publishers to update and add fields within a message by publishing only the updates into the SOW.

This chapter describes how to create delta publish and delta subscribe commands using the AMPS C++ client. For a discussion of this capability, how it works, and how message types support this capability see the [AMPS User Guide](https://docs.crankuptheamps.com/amps-user-guide).
