> ## Documentation Index
> Fetch the complete documentation index at: https://help.the-meridian.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Redis

Redis gives your hosted app a managed in-memory store for caching, sessions, rate limiting, and queues: a dedicated Memorystore instance per environment, wired into your runtime for you.

Redis is a paid runtime add-on. Enable it from **Hosting → Redis**; the price for your app is shown on the button.

## What you get

* A **dedicated 1 GiB Memorystore instance** in your environment's region, reachable privately from your app. It is not exposed to the internet.
* **Connection details injected at deploy time**, so there is nothing to copy into your code:

| Variable | What it holds |
| - | - |
| `REDIS_URL` | The full connection URL, including credentials. Use this one if your client accepts a URL |
| `REDIS_HOST` | The instance host |
| `REDIS_PORT` | The port (`6379` unless the instance says otherwise) |
| `REDIS_PASSWORD` | The auth string, injected from Secret Manager |

`REDIS_URL` and `REDIS_PASSWORD` come from [Secret Manager](/secrets). Their values are omitted from regular add-on and environment responses. If you set a variable of the same name yourself, yours wins and Meridian leaves it alone.

## Enabling it

Provisioning a Memorystore instance takes a few minutes; the page refreshes itself and shows *Provisioning* until the instance is ready. Once it is, the Redis screen shows the host and port, plus ready-made connection snippets for Node, PHP and Ruby. The password stays hidden until a collaborator with **Credentials: Manage** (`credentials.manage`) access to the app selects **Reveal password**. Each reveal is recorded in the organization audit log.

When the instance is ready, Meridian updates your live revision with the connection variables, so there is no need to redeploy. An environment that has not been deployed yet picks them up with its first deploy.

## Removing it

Deleting the add-on removes the instance and everything in it. The variables stop being injected from the next deploy, so remove the code that reads them first.

<Note>
  Redis can only be enabled once your production [environment](/deployment) exists. On a brand-new app, wait for the first environment to finish provisioning.
</Note>


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