# WHATPORT(9944)

## NAME

port 9944 — Substrate / Polkadot JSON-RPC — A blockchain node built on Parity's Substrate — its JSON-RPC endpoint, serving HTTP and WebSocket on the same port.

Protocol: TCP  
IANA registry

## DESCRIPTION

Substrate hardcodes RPC_DEFAULT_PORT = 9944 in substrate/client/cli/src/config.rs, so every node built on the framework — Polkadot, Kusama, parachains, and any `--dev` chain a developer starts locally — listens here by default. Older releases split the endpoint (9944 WebSocket, 9933 HTTP); current ones serve both on 9944. The port carries no IANA registration. Seeing it open means someone is running a node, and a JSON-RPC call like system_chain will tell you which network.

## EXPOSURE

**Do not expose.** Started with --rpc-external or --rpc-methods=unsafe, the endpoint exposes author_* and system_* methods that can insert keys and reconfigure the node. Keep it bound to localhost and put a method-filtering reverse proxy in front if it must be reachable.

## CHECK

```sh
curl -sS -H 'Content-Type: application/json' -d '{"jsonrpc":"2.0","id":1,"method":"system_chain","params":[]}' http://TARGET:9944
```

## SEE ALSO

- source — [polkadot-sdk — substrate/client/cli/src/config.rs (RPC_DEFAULT_PORT)](https://github.com/paritytech/polkadot-sdk/blob/master/substrate/client/cli/src/config.rs) (github.com)
- iana — [IANA port registry — 9944 (no assignment)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=9944) (iana.org)

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HTML: <https://whatport.net/9944/> · JSON: <https://whatport.net/9944.json> · full dataset: <https://whatport.net/ports.json>