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Viewkit

Viewkit is the local CLI tool for creating, testing, and deploying Shinzo Views. It packages a view into a binary bundle (VWL) and submits a deploy transaction to ShinzoHub. It does not process, store, or serve data.

This page is the technical reference for Viewkit: the full command list, filter operators, the deploy pipeline, the VWL wire format, view ID computation, and the on-disk layout of the source repo. For a hands-on walkthrough of building and deploying your first view, see the Create a View quickstart. For the conceptual overview of what Viewkit is and where it sits in the stack, see Views for builders.

Command reference

Filter operators

When querying a deployed view's output collection, DefraDB supports these filter operators:

What happens during deploy

When you run viewkit view deploy, the following happens inside core/service/deploy.go:

1. Tests the view locally (builds a temporary DefraDB instance, applies the lens, validates output).
2. Derives an ECDSA private key from the wallet.
3. For each lens: reads the WASM file and base64-encodes it.
4. Calls viewbundle.NewBundler().BundleView(view) to produce compressed VWL wire bytes.
5. Computes viewID: keccak256(sender.Bytes(), wireBytes).
6. ABI-encodes the transaction: method selector keccak256("register(bytes)")[:4] + ABI-encoded bytes.
7. Sends EVM transaction to 0x0000000000000000000000000000000000000210 (View Registry precompile).
8. Polls for receipt and checks status.

VWL wire format

VWL (View Wire Language) is the binary format for view bundles.

Byte layout

The bundle is a single byte stream written in the order below. Each section is appended directly after the previous one.

WASM binaries can be 70-200+ KB each. zstd compression is applied before the bundle goes on chain. The Host client decompresses when applying.

Two implementations of the wire format exist:

Key functions:

// Encode a view into wire bytes
wireBytes := viewbundle.BundleView(view)

// Decode just the header (without loading the full WASM body)
header := viewbundle.DecodeHeader(encodedBytes)

// Re-encode a modified header
reEncoded := viewbundle.EncodeHeader(decodedValue)

There is a known issue with v0.6.2 of the Host client: it uses viewbundle.UnbundleView() with zstd decompression. Views registered before v0.6.2 may be stored in uncompressed format. If the Host client tries to decompress an uncompressed payload, it fails.

View ID computation

View IDs are deterministic. The same computation runs on the client (Viewkit) and on chain (precompile):

viewID = typeName + "_" + keccak256(senderAddress, wireBytes)

Example:

TestView_0xae1bd91e83f5a71ed4c34e18470ea3c12b9ba3d4a69cfd98717e23cf27f4eccb

Because the same computation runs in both places, the client can predict the view ID before the transaction confirms.

Lenses

Lenses are the WASM transforms that turn raw primitive data into a View's structured output. For the available lenses, their arguments and output fields, lens argument format, determinism requirements, and how to author your own, see the Lens reference.

The view lifecycle across repos

Five repos are involved in the lifecycle from creation to query:

Generator clients are not involved in the View lifecycle. By the time a View is created and applied, the Generator client has already delivered raw data to the Host clients over P2P.

Key files