# Self-hosted Temporal Nexus

> Use Nexus in your self-hosted Temporal Service.

> **ℹ️ Info:**
> NEW TO NEXUS?
>
> This page explains how to self-host Nexus. To learn about Nexus, see the [how Nexus works page](/nexus). To evaluate whether Nexus fits your use case, see the [evaluation guide](/evaluate/nexus).
>

## Enable Nexus

Nexus can be configured by setting static configuration and dynamic configuration entries.

> **📝 Note:**
> Nexus is supported in single-cluster setups only. See [Nexus Architecture](https://github.com/temporalio/temporal/blob/main/docs/architecture/nexus.md) for operational details.

> **📝 Note:**
> Replace `$PUBLIC_URL` with a URL value that's accessible to external callers or internally within the cluster.
> Currently, external Nexus calls are considered experimental so it should be safe to use the address of an internal load balancer for the Frontend Service.

To enable Nexus in your deployment:

1. Enable the HTTP API in the server's static configuration.

   ```yaml
   services:
     frontend:
       rpc:
         # NOTE: keep other fields as they were
         httpPort: 7243

   clusterMetadata:
     # NOTE: keep other fields as they were
     clusterInformation:
       active:
         # NOTE: keep other fields as they were
         httpAddress: $PUBLIC_URL:7243
   ```

2. Set the required dynamic configuration
    1. **Prior to version 1.30.X**, you must set the public callback URL and the allowed callback addresses.

       **NOTE**: the callback endpoint template and allowed addresses should be set when using the experimental
       "external" endpoint targets.

       ```yaml
       component.nexusoperations.callback.endpoint.template:
         # The URL must be publicly accessible if the callback is meant to be called by external services.
         # When using Nexus for cross namespace calls, the URL's host is irrelevant as the address is resolved using
         # membership. The URL is a Go template that interpolates the `NamepaceName` and `NamespaceID` variables.
         - value: https://$PUBLIC_URL:7243/namespaces/{{.NamespaceName}}/nexus/callback
       component.callbacks.allowedAddresses:
         # Limits which callback URLs are accepted by the server.
         # Wildcard patterns (*) and insecure (HTTP) callbacks are intended for development only.
         # For production, restrict allowed hosts and set AllowInsecure to false
         # whenever HTTPS/TLS is supported. Allowing HTTP increases MITM and data exposure risk.
         - value:
             - Pattern: "*" # Update to restrict allowed callers, e.g. "*.example.com"
               AllowInsecure: true # In production, set to false and ensure traffic is HTTPS/TLS encrypted
       ```

    2. **Version 1.30.X+**: Nexus is enabled by default. Only the system callback URL is needed.
       ```yaml
       component.nexusoperations.useSystemCallbackURL:
         - value: true
       ```

## Build and use Nexus Services

See [how Nexus works](/nexus) for an architectural overview, then follow an SDK guide to build your first Nexus Service.

> **💡 Tip:**
> SDK GUIDES
>
> - [Go](/develop/go/nexus/feature-guide) |
>   [Java](/develop/java/nexus) |
>   [Python](/develop/python/nexus) |
>   [TypeScript](/develop/typescript/nexus) |
>   [.NET](/develop/dotnet/nexus)
>