Working with gRPC for Penumbra

The Penumbra pd application exposes a gRPC service for integration with other tools, such as pcli or the web extension. A solid understanding of how the gRPC methods work is helpful when building software that interoperates with Penumbra.

Using gRPC UI

The Penumbra Labs team runs gRPC UI instances for testnet deployments:

You can use this interface to perform queries against the relevant chain. It’s also possible to run gRPC UI locally on your machine, to connect to a local devnet.

Using Buf Studio

The Buf Studio webapp provides a polished GUI and comprehensive documentation. However, a significant limitation for use with Penumbra is that it lacks support for streaming requests, such as penumbra.client.v1alpha1.CompactBlockRangeRequest.

To get started with Buf Studio, you can use the publicly available gRPC endpoint from the testnet deployments run by Penumbra Labs:

  • For the current testnet, use
  • For ephemeral devnets, use

Set the request type to gRPC-web at the bottom of the screen. You can then select a Method and explore the associated services. Click Send to submit the request and view response data in the right-hand pane.

Interacting with local devnets

Regardless of which interface you choose, you can connect to an instance of pd running on your machine, which can be useful while adding new features. First, make sure you’ve joined a testnet by setting up a node on your local machine. Once it’s running, you can connect directly to the pd port via http://localhost:8080.

Alternatively, you can use pclientd. First, make sure you’ve configured pclientd locally with your full viewing key. Once it’s running, you can connect directly to the pclient port via http://localhost:8081.