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

# Protobuf

> Find the CoreWeave Sandbox Protobuf definitions, the host that serves each service, and the generated SDKs.

You can find the Protobuf definitions for the CoreWeave Sandbox API in the Buf module at [`buf.build/coreweave/sandbox`](https://buf.build/coreweave/sandbox). Use them when you integrate from a language that has no first-party CoreWeave client, or when you need an RPC that the [Python client](/products/sandboxes/client) or the TypeScript client (`@coreweave/cwsandbox`) doesn't expose.

The [module page](https://buf.build/coreweave/sandbox) is the reference for the API itself: every service and field, the JSON encoding rules, and the error contract. Use `coreweave.sandbox.v1` for new integrations. The earlier `coreweave.sandbox.v1beta2` package is still served for existing clients, and also carries profile templates and runner enrollment.

<Note>
  CoreWeave Serverless sandboxes are in public preview.
</Note>

## Endpoints

Every RPC is served over the [Connect protocol](https://connectrpc.com/), and the same endpoints accept gRPC and gRPC-Web clients. The `v1` services are split across two hosts, plus a per-sandbox endpoint for direct connections:

| Host                            | Serves                                                                                                                                                                                                                             |
| ------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `https://api.cwsandbox.com`     | `SandboxService`, `DiscoveryService`, `VolumeService`, `NetworkService`, and `SettingsService`.                                                                                                                                    |
| `https://api.coreweave.com`     | `RunnerManagementService` and `SandboxTemplateService`. `PlacementOrgConfigService` is also served here, for platform operators only. See the [API overview](/products/sandboxes/reference/control-plane-api).                     |
| Per-sandbox data-plane endpoint | `SandboxDataPlaneService`. `SandboxService.ConnectSandbox` returns the endpoint URI, a short-lived client certificate, and a trust bundle. See [Direct sandbox connections](/products/sandboxes/client/guides/direct-connections). |

`NetworkService` isn't available yet: every RPC returns `UNIMPLEMENTED`. More generally, not every RPC is enabled for every organization or [placement mode](/products/sandboxes/get-started#choose-a-placement-mode). A call that isn't available returns `UNIMPLEMENTED` with reason `CWSANDBOX_NOT_IMPLEMENTED`.

Requests authenticate with a CoreWeave API access token. For how to create one and grant the `SANDBOX_USER` or `SANDBOX_ADMIN` IAM action, see [Authentication](/products/sandboxes/reference/control-plane-api#authentication).

## Install a generated SDK

The Buf Schema Registry builds SDKs for the module on demand. The following commands install common language and plugin combinations:

```bash title="Install a generated SDK" theme={"system"}
# Go: Connect clients and message types
go get buf.build/gen/go/coreweave/sandbox/connectrpc/go@latest
go get buf.build/gen/go/coreweave/sandbox/protocolbuffers/go@latest

# Python: message types and gRPC stubs
pip install coreweave-sandbox-protocolbuffers-python coreweave-sandbox-grpc-python \
  --extra-index-url https://buf.build/gen/python

# TypeScript: message types, paired with @connectrpc/connect
npm config set @buf:registry https://buf.build/gen/npm/v1/
npm install @buf/coreweave_sandbox.bufbuild_es
```

For every other language and plugin combination, see the [SDKs tab](https://buf.build/coreweave/sandbox/sdks) on the module page. To generate code locally instead, point `buf generate` at the module: `buf generate buf.build/coreweave/sandbox`.

## See also

* [Sandboxes architecture](/products/sandboxes/architecture): how the gateway brokers runtime requests, and the control plane and data plane split.
* [API overview](/products/sandboxes/reference/control-plane-api): authentication, pagination, field masks, and error handling for the control plane.
* [Sandbox Python client](/products/sandboxes/client): the higher-level `cwsandbox` client built on this API.
* [Direct sandbox connections](/products/sandboxes/client/guides/direct-connections): how a client reaches `SandboxDataPlaneService` over mutual TLS.


## Related topics

- [API overview](/products/sandboxes/reference/control-plane-api.md)