Canton Builder Tool

One command. Full Canton Network on your laptop.

Built for hackathons, bootcamps, and anyone who needs a local Canton Network without waiting for DevNet whitelisting. Three validators, a synchronizer, wallet UIs, Canton Coin, Scan UI, the whole official Splice LocalNet stack.

Install

macOS / Linux (WSL 2 on Windows):

curl -fsSL https://raw.githubusercontent.com/Jatinp26/Canton-Builder-Tool/main/install.sh | bash

Then reload your shell:

source ~/.zshrc   # zsh
source ~/.bashrc  # bash

Requirements:

• Docker Desktop with ≥ 8 GB memory allocated (Settings → Resources → Memory)
• curl, jq, git — available via brew (macOS) or apt (Linux)
• macOS or Linux only. Windows: use WSL 2.

The installer handles PATH setup and /etc/hosts entries for *.localhost domains.

Commands

canton builder start                        # download bundle + boot LocalNet

canton builder stop                         # stop containers (data preserved)

canton builder status                       # health check + port reference

canton builder deploy ./my-app-0.0.1.dar    # upload your DAR to both participants

canton builder logs                         # tail all logs

canton builder logs <service>               # tail one service

canton builder reset                        # wipe everything, start clean

What Starts

Service	URL	Credential
App User Wallet UI	http://wallet.localhost:2000	app-user
App Provider Wallet UI	http://wallet.localhost:3000	app-provider
Scan UI	http://scan.localhost:4000	-
SV UI	http://sv.localhost:4000	sv
App Provider JSON API	http://localhost:3975	-
App User JSON API	http://localhost:2975	-
SV JSON API	http://localhost:4975	-
App Provider Ledger API (gRPC)	localhost:3901	-
App User Ledger API (gRPC)	localhost:2901	-
SV Ledger API (gRPC)	localhost:4901	-
PostgreSQL	localhost:5432	-

First Run

On canton builder start, the tool:

1. Downloads the official Splice LocalNet bundle from the Splice GitHub release (One-time only cached at ~/.canton-builder/bundle/)
2. Pulls the Canton/Splice Docker images (~5 min, also cached)
3. Boots the full network using the official LocalNet compose configuration

Subsequent runs skip steps 1 and 2 entirely and boot in ~30 seconds.

Deploying Your DAR

Build your Daml project with dpm build, then:

canton builder deploy ./your-project/.daml/dist/your-project-0.0.1.dar

Uploads your DAR to both the App Provider and App User participants, retrieves your package ID, and prints the template ID format for API calls.

Interacting With Your Contracts

Once deployed, use the JSON Ledger API to create contracts, exercise choices, and query state.

What It Is / Isn't

Is: A CLI that has the official Splice LocalNet, the same Docker Compose configuration that Digital Asset ships with every Splice release, invoked with the exact commands from the official docs. No custom compose files, no approximations.

Isn't: A replacement for cn-quickstart. Quickstart is a full developer project template with a reference app, Java backend, and React frontend. This tool is just the network layer to bring your own Daml project.

Troubleshooting

First run is slow Normal, the Splice bundle and Docker images download on first run. Everything is cached after that.

Containers crash on startup Docker memory. Go to Docker Desktop Settings, Under Resources goto Memory and set to 8 GB minimum.

*.localhost domains don't resolve

echo "127.0.0.1  wallet.localhost scan.localhost sv.localhost" | sudo tee -a /etc/hosts

Weird state / things not working

canton builder reset
canton builder start

See what's failing

canton builder logs
canton builder logs canton     
canton builder logs splice     

Re-download the bundle (if corrupted or upgrading)

rm -rf ~/.canton-builder/bundle
canton builder start

Upgrading LocalNet version

Edit ~/.canton-builder/.env and change IMAGE_TAG:

IMAGE_TAG=0.5.11 

Then reset and restart:

canton builder reset
rm -rf ~/.canton-builder/bundle  
canton builder start

Part of the Canton Developer Hub

This is the fast start layer of the BuidL Experience on Canton.

Want more?	Where to go
Understand LocalNet deeply, use PQS, integrate wallets	LocalNet Deployment Guide
Build a full Canton app with backend, auth, frontend	cn-quickstart
Browse all Canton tools, SDKs, and APIs	Canton Dev Toolings Guide

Built by Jatin Pandya, Developer Relations Manager, Canton Foundation.