Splice Wallet Kernel

A TypeScript framework for building wallet integrations on the Canton Network. It provides the Wallet Gateway (server and browser extension), the dApp SDK, the Wallet SDK, and a set of shared core modules.

Architecture

┌─────────────┐      dApp API (CIP-103)    ┌──────────────────┐     Ledger API      ┌──────────────────┐
│   Your dApp │ ◄────────────────────────► │  Wallet Gateway  │ ◄─────────────────► │ Canton Validator │
│ (dApp SDK)  │    (HTTP / postMessage)    │                  │                     │                  │
└─────────────┘                            │  ┌────────────┐  │     Signing         └──────────────────┘
       │                                   │  │  User API  │  │
       │      User interactions            │  │  User UI   │  │     ┌──────────────────┐
       └──────────────────────────────────►│  └────────────┘  │ ◄──►│ Signing Provider │
              (User UI / User API)         │                  │     │ (Participant,    │
                                           └──────────────────┘     │  Fireblocks, …)  │
                                                                    └──────────────────┘

• dApp → Wallet Gateway: dApps use the dApp SDK to call the dApp API.
• User → Wallet Gateway: Users manage wallets and approve transactions via the User UI.
• Wallet Gateway → Canton / Signing: The Gateway authenticates to validator Ledger APIs and forwards signing requests to the configured signing provider.

dApp API (CIP-103)

The dApp API is a JSON-RPC 2.0 interface specified by CIP-103. It defines how dApps communicate with wallet providers on the Canton Network. Key methods include:

The dApp SDK (@canton-network/dapp-sdk) implements this protocol and adds a higher-level API, multi-transport support, and an EIP-1193-style provider (window.canton).

Wallet SDK

The Wallet SDK (@canton-network/wallet-sdk) is a TypeScript SDK for wallet providers and exchanges integrating directly with the Canton Network. Unlike the dApp SDK (which talks to a Wallet Gateway), the Wallet SDK operates at a lower level — authenticating to synchronizers, allocating parties with external keypairs, reading active contracts, and signing and submitting transactions.

Key capabilities:

• Authenticate and connect to a Canton synchronizer
• Allocate parties with an external keypair
• Read active contracts on the ledger
• Decode and validate prepared transactions
• Sign and submit transactions via the Ledger API
• Integrate with the Splice Token Standard

See the Wallet SDK README and the integration guide for usage details.

Project Structure

Wallet Gateway

Two implementations of the Wallet Gateway, both exposing the same dApp API and User API:

Package	Path	Description
@canton-network/wallet-gateway-remote	wallet-gateway/remote	Server-side implementation over HTTP (Express.js). Connects to SQL stores and external signing providers.
@canton-network/wallet-gateway-extension	wallet-gateway/extension	[NOT IMPLEMENTED YET] Client-side implementation as a Manifest V3 browser extension. Uses browser storage for persistence and in-browser signing.

SDKs

Package	Path	Description
@canton-network/dapp-sdk	sdk/dapp-sdk	Browser SDK for dApp development. Implements the CIP-103 dApp API with multi-transport support (HTTP, postMessage).
@canton-network/wallet-sdk	sdk/wallet-sdk	SDK for wallet providers and exchanges to integrate with Canton and the Splice Token Standard.

Core Modules

Shared libraries used by the Wallet Gateway, SDKs, and signing providers:

Package	Path	Description
Store
core-wallet-store	core/wallet-store	Store interface for wallets, sessions, networks, IDPs, and transactions
core-wallet-store-sql	core/wallet-store-sql	SQL implementation (SQLite / PostgreSQL) via Kysely
core-wallet-store-inmemory	core/wallet-store-inmemory	In-memory implementation for testing and development
Signing
core-signing-lib	core/signing-lib	Core library and interfaces for signing driver implementations
core-signing-store-sql	core/signing-store-sql	SQL persistence for signing keys and transactions
core-signing-internal	core/signing-internal	Internal (wallet-kernel) signing driver using Ed25519
core-signing-participant	core/signing-participant	Canton participant-managed signing driver
core-signing-fireblocks	core/signing-fireblocks	Fireblocks signing driver integration
core-signing-blockdaemon	core/signing-blockdaemon	Blockdaemon signing driver integration
RPC & Transport
core-types	core/types	Shared types and transport-agnostic parsers
core-rpc-transport	core/rpc-transport	RPC transport implementations
core-rpc-errors	core/rpc-errors	Standardized JSON-RPC error types
core-rpc-generator	core/rpc-generator	Code generator for JSON-RPC interfaces
Auth & Ledger
core-wallet-auth	core/wallet-auth	Authentication middleware and user management (JWT, OAuth)
core-ledger-client	core/ledger-client	TypeScript Canton Ledger API client (generated from OpenAPI)
core-ledger-client-types	core/ledger-client-types	Type definitions for the Ledger API client
UI & Clients
core-wallet-ui-components	core/wallet-ui-components	Reusable Lit web components for wallet UIs
core-wallet-user-rpc-client	core/wallet-user-rpc-client	Generated RPC client for the User API
core-wallet-dapp-rpc-client	core/wallet-dapp-rpc-client	Generated RPC client for the dApp API
Splice
core-splice-client	core/splice-client	Client for Splice network services
core-splice-provider	core/splice-provider	Splice network provider integration
core-token-standard	core/token-standard	Canton Token Standard implementation

Examples

Path	Description
examples/ping	Minimal dApp demonstrating connect, prepare, and execute flows
examples/portfolio	Portfolio dApp showcasing account listing and transaction history

Documentation

Path	Description
docs/wallet-gateway	Wallet Gateway developer guide (Sphinx)
docs/wallet-integration-guide	Step-by-step integration guide with code examples
docs/CONTRIBUTING.md	Contribution guidelines
docs/GLOSSARY.md	Terminology reference

Getting Started

Prerequisites

• Node.js 20+
• Yarn 4 (Corepack)
• A running Canton participant node (or use the included local setup)

Quick Start

# Install dependencies
yarn install

# Build everything
yarn build:all

# Start all services (Wallet Gateway, mock OAuth, Example dApps, etc.)
yarn start:all

# Start a local Canton Participant Node
yarn start:canton

Active processes can be monitored with:

yarn pm2 list

To stop everything:

yarn stop:all

Running the Browser Extension

TBD

Contributing

For information about contributing, please refer to the Contributing Guide.

License

Apache-2.0