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cn-quickstart - Canton Network Docs
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Documentation Index

Fetch the complete documentation index at: https://docs.canton.network/llms.txt

Use this file to discover all available pages before exploring further.

The cn-quickstart repository is a complete example application that demonstrates how to build, test, and run a Canton Network application. It includes Daml smart contracts, a Java backend, a React frontend, and a LocalNet environment for local development.

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Repository Overview

Clone the repository: 
git clone https://github.com/digital-asset/cn-quickstart
cd cn-quickstart
direnv allow
cd quickstart
The repository uses Nix and Direnv for reproducible development dependencies. If you prefer not to use Nix, work directly in the quickstart/ directory and manage dependencies (JDK, Node.js, dpm) manually.

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Project Structure

cn-quickstart/
  .envrc                    # Nix/Direnv activation
  nix/                      # Nix development dependencies
  quickstart/
    Makefile                # Build and run commands
    compose.yaml            # Docker Compose configuration
    .env                    # Environment variables
    daml/                   # Daml smart contracts
      Licensing/
        AppInstall.daml     # User onboarding workflow
        License.daml        # License management
        Util.daml           # Helper functions
      dars/                 # Splice DAR dependencies
    backend/                # Java Spring Boot backend
      src/main/java/...
        ledger/             # Ledger API client
        repository/         # PQS queries
        pqs/                # SQL generation
        service/            # REST endpoints
        security/           # OAuth2 auth
    frontend/               # React TypeScript frontend
      src/
        components/         # UI components
        api/                # Generated API client
    common/
      openapi.yaml          # Shared API definition
    docker/                 # Docker image definitions
      modules/
        localnet/           # LocalNet configuration
    config/                 # Service configuration files

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The Reference Application

cn-quickstart implements a software licensing workflow with four parties:
  • App Provider — Creates and sells licenses
  • App User — Purchases and holds licenses
  • Super Validator (SV) — Operates the payment infrastructure
  • DSO Party — The decentralized synchronizer operator for Canton Coin
The Provider and User each run on their own validator. License purchases involve Canton Coin payments processed through the Splice wallet system.

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Running the Application

cd quickstart
make install-daml-sdk    # Install the Daml SDK
make setup               # Select deployment profile
make build               # Compile contracts, backend, frontend
make start               # Launch LocalNet and all services
Once running, the frontend is accessible in your browser. See the QuickStart walkthrough for a step-by-step guide.

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Extending the Example

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Adding Your Own Templates

Create new .daml files in the daml/ directory. After writing your templates: 
dpm build                # Compile
dpm test                 # Run tests
make build               # Rebuild everything including codegen
make restart             # Restart services
The build system regenerates Java bindings from the updated DAR file, so your backend can reference the new templates immediately.

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Modifying the Backend

The backend follows a standard Spring Boot layout. To add a new endpoint:
  1. Define the endpoint in common/openapi.yaml
  2. Add the service implementation in backend/src/main/java/.../service/
  3. Add PQS queries in repository/ if you need to read contract data
  4. Add Ledger API commands in ledger/ if you need to submit transactions
  5. Rebuild with make build-backend

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Custom Frontend

The React frontend consumes the backend’s REST API. To modify it:
  1. Update or add components in frontend/src/components/
  2. Regenerate the API client if you changed openapi.yaml
  3. Rebuild with make build-frontend
The frontend never interacts with the Ledger API directly — all ledger access goes through the backend.

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Switching Architectures

cn-quickstart uses a fully mediated architecture (backend handles all ledger access). You can switch to a CQRS pattern where the frontend submits commands directly to the Ledger API using TypeScript bindings generated by dpm codegen-js. See SDKs and APIs for a comparison of both approaches.
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