# CLIENT CACHING This command controls the tracking of the keys in the next command executed by the connection, when tracking is enabled in `OPTIN` or `OPTOUT` mode. Please check the [client side caching documentation](https://redis.io/docs/latest/develop/clients/client-side-caching) for background information. When tracking is enabled Redis, using the [`CLIENT TRACKING`](https://redis.io/docs/latest/commands/client-tracking) command, it is possible to specify the `OPTIN` or `OPTOUT` options, so that keys in read only commands are not automatically remembered by the server to be invalidated later. When we are in `OPTIN` mode, we can enable the tracking of the keys in the next command by calling `CLIENT CACHING yes` immediately before it. Similarly when we are in `OPTOUT` mode, and keys are normally tracked, we can avoid the keys in the next command to be tracked using `CLIENT CACHING no`. Basically the command sets a state in the connection, that is valid only for the next command execution, that will modify the behavior of client tracking. ## Return information {{< multitabs id="client-caching-return-info" tab1="RESP2" tab2="RESP3" >}} [Simple string reply](../../develop/reference/protocol-spec#simple-strings): `OK` or an error if the argument is not "yes" or "no". -tab-sep- [Simple string reply](../../develop/reference/protocol-spec#simple-strings): `OK` or an error if the argument is not "yes" or "no".