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

# Storage Providers

> To maintain control over your data and ensure high performance, utilize different storage providers to store router artifacts on Amazon S3, while still using our Cosmo Managed offering.

The router is a stateless component, allowing it to be scaled horizontally without requiring persistence. However, it needs to fetch artifacts such as the execution configuration and persisted operations from a storage source. By default, the router fetches these from the Cosmo CDN. You can configure custom storage providers to use your own infrastructure instead.

For both mechanisms, different storage providers can be used:

* **CDN**: The default provider used by Cosmo Cloud.

* **Amazon S3**: An object storage protocol. We support any S3 compatible object-storage e.g. Minio and AWS.

When using a custom storage provider, you are responsible for manually pushing those artifacts as part of your CI process.

## Define a provider

Before you can use a storage provider, you have to define it in the `storage_providers` section of your `config.yaml` file. Each provider is given an `id` that you reference from other configuration sections.

<CodeGroup>
  ```yaml config.yaml theme={"system"}
  version: 1
  storage_providers:
    s3:
    - id: "s3"
      endpoint: "localhost:10000"
      bucket: "cosmo"
      access_key: "key"
      secret_key: "secret"
      region: "us-east-1"
      secure: false
  ```
</CodeGroup>

<Info>
  **secure** has to be set to `true` when you point to an S3 that uses **https\://**
</Info>

If you are using EC2 or EKS on AWS and have configured [`node IAM roles`](https://docs.aws.amazon.com/eks/latest/userguide/create-node-role.html) you don't need to provide an `access_key` or `secret_key` and the S3 client will handle this on your behalf.

<CodeGroup>
  ```yaml config.yaml theme={"system"}
  version: 1
  storage_providers:
    s3:
    - id: "s3"
      endpoint: "s3.amazonaws.com"
      bucket: "cosmo"
      region: "us-east-1"
      secure: true
  ```
</CodeGroup>

## Using storage providers

Once a provider is defined, you reference it by `provider_id` in the configuration of each feature. The following features support custom storage providers:

* [**Execution config**](/router/configuration#execution-config-options) — load the router execution configuration from S3 instead of the Cosmo CDN.
* [**Persisted operations**](/router/persisted-queries/persisted-operations#using-a-custom-storage-provider) — load individual persisted operations or the PQL manifest from S3.

## Configuration via environment variables

Storage providers can also be configured entirely through environment variables using indexed notation. This is useful in containerized deployments or when secrets should not live in config files. See the [configuration reference](/router/configuration#storage-providers) for the full list of environment variables for each provider type.

## Best Practices

* Create different S3 credentials for READ and WRITE to reduce the attack surface.