> For the complete documentation index, see [llms.txt](https://docs.xandtech.fr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xandtech.fr/home/xplayercurrencies/integrations/cross-server-redis.md).

# Cross-Server Sync (Redis)

Optional real-time balance sync across several servers sharing the same MySQL database (a network). Without it, another server only sees a balance change once the player quits and rejoins there - with it, a change on one server instantly updates the in-memory balance of any other server where that player happens to be online, via Redis pub/sub.

{% hint style="warning" %}
Only takes effect when `storage.type` is `MYSQL` (see [Installation](/home/xplayercurrencies/getting-started/installation.md#choosing-a-storage-backend)) - every server on the network must point at the **same** MySQL database. If `storage.type` isn't `MYSQL`, this section is safely ignored with a warning.
{% endhint %}

## Setup

In `config.yml`, on every server sharing the network:

```yaml
storage:
  type: MYSQL
  mysql:
    host: your-shared-mysql-host
    # ...

cross-server:
  enabled: true
  redis:
    host: localhost
    port: 6379
    password: ""
    database: 0
    channel: xplayercurrencies:balance-sync
```

| Key             | Description                                                                                                                                      |
| --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| `redis.channel` | The pub/sub channel name - only needs changing if multiple, unrelated XPlayerCurrencies networks happen to share the same Redis server/database. |

This is hot-swappable on `/currencies admin reload` (unlike `storage.type` itself, which needs a restart).

## What it does (and doesn't) do

* A balance change is still written to the shared MySQL database first (the source of truth) - Redis only pushes the **in-memory** update to other servers so they don't have to wait for the player to reconnect there to see it.
* Every read-modify-write against MySQL is still transactionally safe on its own even without Redis - this feature is purely about **visibility latency**, not correctness.
* No Redis connection needed for a single standalone server - leave `cross-server.enabled: false` (the default).

Next: [API & Events](/home/xplayercurrencies/developer/api.md).


---

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