---
alwaysopen: false
categories:
- docs
- operate
- rc
description: null
hideListLinks: true
linktitle: Create service
title: Create a LangCache service
weight: 5
---

Redis LangCache provides vector search capabilities and efficient caching for AI-powered applications. This guide walks you through creating and configuring a LangCache service in Redis Cloud.

## Prerequisites

To create a LangCache service, you will need:

- A Redis Cloud database. If you don't have one, see [Create a database]({{< relref "/operate/rc/databases/create-database" >}}).

    {{< note >}}
LangCache does not support the following databases during public preview:
- Databases with a [CIDR allow list]({{< relref "/operate/rc/security/cidr-whitelist" >}})
- [Active-Active]({{< relref "/operate/rc/databases/active-active" >}}) databases
- Databases with the [default user]({{< relref "/operate/rc/security/access-control/data-access-control/default-user" >}}) turned off
    {{< /note >}}

- An API key for your embedding provider, if not using the default Redis embedding provider. LangCache supports [OpenAI](https://platform.openai.com/api-keys) and the Redis embedding provider during public preview.

## Create a LangCache service

From the [Redis Cloud console](https://cloud.redis.io/), select **LangCache** from the left-hand menu. 

If you have not already created a LangCache service, you'll see a page with an introduction to LangCache. Otherwise, select **New service** to go to the LangCache introduction page.

{{<image filename="images/rc/langcache-new-service.png" alt="The New service button." width="150px" >}}

From here: 

- Select **Quick create** to create a LangCache service with default settings using your Free 30MB database. If you haven't created a Free database yet, Redis Cloud will create one and set up the LangCache service for you.

    {{<image filename="images/rc/langcache-quick-create.png" alt="The Quick create button." width="150px" >}}

    After Redis Cloud creates your LangCache service, a window containing your LangCache service key will appear. Select **Copy** to copy the key to your clipboard. 

    {{<image filename="images/rc/langcache-service-key.png" alt="The LangCache service key window. Use the Copy button to save the service key to the clipboard." >}}

    {{<warning>}}
This is the only time the value of the user key is available. Save it to a secure location before closing the dialog box.<br/><br/>

If you lose the service key value, you will need to [generate a new service key]({{< relref "/operate/rc/langcache/view-edit-cache#replace-service-api-key" >}}) to be able to use the LangCache API.
    {{</warning>}}

    After your cache is created, you can [use the LangCache API]({{< relref "/operate/rc/langcache/use-langcache" >}}) from your client app.

    You can also [view and edit the cache]({{< relref "/operate/rc/langcache/view-edit-cache" >}}) and [monitor the cache's performance]({{< relref "/operate/rc/langcache/monitor-cache" >}}).

- If you want to customize your LangCache service, select **Create custom service**.

    {{<image filename="images/rc/langcache-custom-service.png" alt="The Create custom service button." width="150px" >}}

    This takes you to the **Create LangCache service** page. The page is divided into the following sections:

    1. The [General settings](#general-settings) section defines basic properties of your service.
    1. The [Embedding settings](#embedding-settings) section defines the embedding model used by your service.
    1. The [Attributes settings](#attributes-settings) section allows you to define attributes for your service.

### General settings

The **General settings** section defines basic properties of your service.

{{<image filename="images/rc/langcache-general-settings.png" alt="The General settings section." >}}

| Setting name          |Description|
|:----------------------|:----------|
| **Service name** | Enter a name for your LangCache service. We recommend you use a name that describes your service's purpose. |
| **Select database** | Select the Redis Cloud database to use for this service from the list. |
| **TTL** | The time to live (TTL) for cache entries, in milliseconds. Default: `No expiration` - items in the cache will remain until manually removed. |
| **User for this service** | The [database access user]({{< relref "/operate/rc/security/access-control/data-access-control/role-based-access-control" >}}) to use for this service. LangCache only supports the [`default` user]({{< relref "/operate/rc/security/access-control/data-access-control/default-user" >}}) during public preview. |

### Embedding settings

The **Embedding settings** section defines the embedding model used by your service.

{{<image filename="images/rc/langcache-embedding-settings.png" alt="The Embedding settings section." >}}

Required settings depend on the embedding provider you select. 

| Setting name          |Description|
|:----------------------|:----------|
| **Embedding Provider** | The embedding provider to use for your service. Select between `Redis`, `OpenAI`, and `Bring your own`. <br/>Any embedding provider you use must support the [OpenAI embeddings API](https://platform.openai.com/docs/api-reference/embeddings). |
| **Embedding provider API key** | Enter your embedding provider's API key *(`OpenAI` and `Bring your own` embedding providers only)* |
| **Embedding provider URL** | Enter your embedding provider's API URL *(`Bring your own` embedding provider only)* |
| **Model** | Select or enter the embedding model to use for your service. |
| **Similarity threshold** | Set the minimum similarity score required to consider a cached response a match. Range: `0.5` to `1.0`. Default: `0.85`<br/><br/>A higher value means more precise matches, but if it's too high, you will compromise on the number of matches and may lose relevant matches. A lower value means more matches, but may include less relevant matches. We recommend starting between `0.8` and `0.9` and then fine-tuning based on your results. |

### Attributes settings

Attributes provide powerful scoping capabilities for your LangCache operations. Think of them as tags or labels that help you organize and manage your cached data with precision.

The **Attributes settings** section allows you to define attributes for your service. It is collapsed by default.

{{<image filename="images/rc/langcache-attribute-settings.png" alt="The Attributes settings section." >}}

LangCache allows you to define up to 5 custom attributes that align with your specific use case. To add a new attribute:

1. Select **Add attribute**.

    {{<image filename="images/rc/langcache-add-attribute.png" alt="The Add attribute button." width="150px" >}}

1. Give your custom attribute a descriptive name and select the check mark button to save it.

    {{<image filename="images/rc/langcache-custom-attributes.png" alt="The custom attributes section. Select the Confirm add attribute button to save your attribute." >}}

After you save your custom attribute, it will appear in the list of custom attributes. Use the **Delete** button to remove it.

{{<image filename="images/rc/icon-delete-lb.png" width="36px" alt="Select the Delete button to delete the selected attribute." >}}

You can also select **Add attribute** again to add an additional attribute.

{{<image filename="images/rc/langcache-add-attribute.png" alt="The Add attribute button." width="150px" >}}

### Create service

When you are done setting the details of your LangCache service, select **Create** to create it.

{{<image filename="images/rc/button-access-management-user-key-create.png" alt="Use the Create button to create a LangCache service." >}}

A window containing your LangCache service key will appear. Select **Copy** to copy the key to your clipboard. 

{{<image filename="images/rc/langcache-service-key.png" alt="The LangCache service key window. Use the Copy button to save the service key to the clipboard." >}}

{{<warning>}}
This is the only time the value of the user key is available. Save it to a secure location before closing the dialog box.<br/><br/>

If you lose the service key value, you will need to [generate a new service key]({{< relref "/operate/rc/langcache/view-edit-cache#replace-service-api-key" >}}) to be able to use the LangCache API.
{{</warning>}}

You'll be taken to your LangCache service's **Configuration** page. You'll also be able to see your LangCache service in the LangCache service list.

{{<image filename="images/rc/langcache-service-list.png" alt="The LangCache service in the LangCache service list." >}}

If an error occurs, verify that:
- Your database is active.
- You have provided a valid OpenAI API key.
- You have provided valid values for all the required fields.

For help, [contact support](https://redis.io/support/).

## Next steps

After your cache is created, you can [use the LangCache API]({{< relref "/operate/rc/langcache/use-langcache" >}}) from your client app.

You can also [view and edit the cache]({{< relref "/operate/rc/langcache/view-edit-cache" >}}) and [monitor the cache's performance]({{< relref "/operate/rc/langcache/monitor-cache" >}}).