Product Preview Network (PPN)

Warning

The following is a prototype, reference implementation, and proof-of-concept. This open source code is provided for research, experimentation, and developer education only. This code has not been audited, is actively experimental, and may contain bugs, vulnerabilities, or incomplete features. Use at your own risk.

A complete Polkadot ecosystem on your machine, in one command: a Paseo relay chain with six validators, plus Asset Hub (2-second blocks via elastic scaling), People, Bulletin and Web3 Storage, plus the Ethereum RPC, IPFS, identity backend and storage provider those chains expect, already wired together.

Start it

npm install -g @parity/ppn
ppn start

Needs Node.js 24+. No clone: the CLI ships the network definitions, so ppn start downloads what it is missing and spawns. The first run pulls ~500 MB of binaries and runtimes into ~/.ppn and later runs reuse them. ppn kill stops everything.

When it is up, the dashboard at http://127.0.0.1:8090 lists every chain, service and endpoint. ppn show prints the same as text, and ppn networks lists what else this install can run.

Two things worth doing before the first start:

• Set a GitHub token. Everything comes from public releases, so this is not about access: it is that a fetch pulls a lot of assets and GitHub throttles anonymous requests hard. Run gh auth login, or set GITHUB_TOKEN.
• On Apple Silicon, disable IPv6, per polkadot-sdk#8918: sudo networksetup -setv6off Wi-Fi (undo with -setv6automatic).

What you would use it for

Develop against the whole stack, not a mock. Contracts on Asset Hub through eth-rpc at :8545, identity on People, storage on Bulletin and Web3 Storage. Everything speaks to everything, the way it does in production.

Start from real state instead of genesis. A fork continues from a live network's block, so contracts, registrations and balances are already there.

ppn start --fork                 # from the latest published snapshot
ppn start --fork paseo-next-v2   # a different network

Test a build before it ships. Any binary or runtime can be repointed without editing anything, which is what makes this useful as a release gate. Run the full network against a candidate and see what breaks.

ppn start --binary polkadot-omni-node=file:/path/to/your/build
ppn start --runtime asset-hub=file:/path/to/runtime.wasm
ppn start --binary polkadot-omni-node=paritytech/release-automation@polkadot-weekly2026w37-rc1

Rehearse a runtime upgrade. Authorize and apply one against a chain that is already running, and watch it cross the boundary.

ppn upgrade asset-hub ./asset_hub_runtime.wasm

Run a preview network for your team. See docs/DEPLOYING-YOUR-OWN.md.

The network

	Endpoint
Relay (alice … ferdie)	ws://127.0.0.1:10000 – 10005	6 validators, Paseo
Asset Hub	ws://127.0.0.1:10020	2-second blocks, elastic scaling
People	ws://127.0.0.1:10010	individuality
Bulletin	ws://127.0.0.1:10030	transaction storage
Web3 Storage	ws://127.0.0.1:10040	storage parachain
Dashboard	http://127.0.0.1:8090	status UI and API for all of the above
Ethereum RPC	http://127.0.0.1:8545	JSON-RPC onto Asset Hub
IPFS	:8080 gateway, :5001 API
Identity backend	http://127.0.0.1:8092	auth, usernames, tickets; /docs for the API

Docker

DOCKER=1 make start

Linux only. p2p networking fails on Apple Silicon under x86_64 emulation, so use make start.

Every endpoint in the table above is published to the host. The dashboard is read-only here, because a published port is reachable from your network and the sudo actions only stay open on a loopback bind. Set DASHBOARD_ACTIONS_TOKEN if you want them.

Running a network of your own

The networks above are descriptors, not code: networks/<name>.json naming the binary, release and runtime for every chain. Point ppn at your own set and it runs those instead.

export PPN_HOME=~/my-network     # holds networks/my-net.json
ppn networks                     # what it can see
ppn show my-net                  # what that resolves to

$PPN_HOME is also where state lives: bin/ for downloaded binaries, data/ for chain state. Without it, ppn walks up from the working directory looking for a networks/ folder, then falls back to ~/.ppn. See networks/README.md for the schema.

Working on PPN itself

git clone https://github.com/paritytech/previewnet-engine.git
cd previewnet-engine
make start

A clone is a workspace like any other, so the walk-up above finds its networks/. What a clone adds is make, a front door for the common things: every target delegates to ppn, so make start FORK=1 NETWORK=devnet is ppn start --fork devnet. make help lists the targets, make doctor checks your machine, and ppn <command> --help lists the flags.

make test runs the integration suite, which spawns a real network; make test-unit is the fast one. ARCHITECTURE.md is the map.

Docs

ARCHITECTURE.md	workspace layout, package boundaries, what a release contains
FORK.md	how forking works, and what a bundle is
DASHBOARD.md	the status UI, its API, and the action plane
PROFILES.md	local vs deployable: funded accounts, sudo, signing keys
RUNTIME-UPGRADE.md	upgrading a chain that is running
DEVICE-UNIQUENESS-BACKEND.md	identity backend roles and endpoints
DEPLOYING-YOUR-OWN.md	running this for a team

Security

Warning

The following is a prototype, reference implementation, and proof-of-concept. This open source code is provided for research, experimentation, and developer education only. This code has not been audited, is actively experimental, and may contain bugs, vulnerabilities, or incomplete features. Use at your own risk.

Concretely: the default profile deliberately runs well-known development keys (//Alice and friends) as funded sudo accounts, so do not point it at anything holding real value. Read PROFILES.md before running it anywhere long-lived or reachable by others.

Before deploying this for real use cases, you are responsible for:

• Reviewing the code yourself. We publish a reference, not a hardened production build.
• Checking that the dependencies are up to date and free of known vulnerabilities.
• Securing your own deployment environment: keys, secrets, network configuration.
• Tracking the latest tagged release for security fixes. Older releases are not backported.

To report a vulnerability, follow the Parity security policy.

Parity's deployment

Parity runs a preview network from this engine at previewnet.substrate.dev. That deployment, its server tooling and its release pipeline live in a separate repo; this one is the engine it installs.

License

Apache-2.0. See LICENSE.

Copyright 2026 Parity Technologies