Multi-Chain & Ports

Run several instances side by side

Every instance binds six ports (RPC, gRPC, REST, P2P, gRPC-Web, pprof) — EVM chains add a seventh. Defaults collide as soon as you run a second chain, and hand-assigning ports gets tedious and error-prone. Use findFreePorts():

import { findFreePorts, Instance } from 'starskiff';
 
const [ports1, ports2] = await Promise.all([findFreePorts(), findFreePorts()]);
 
const chain1 = Instance.simd({ chainId: 'chain-1', ...ports1 });
const chain2 = Instance.simd({ chainId: 'chain-2', ...ports2 });
 
await Promise.all([chain1.start(), chain2.start()]);

Each call returns a PortSet of distinct, currently-free ports:

Key	Instance parameter it fills
`rpcPort`	CometBFT RPC
`grpcPort`	gRPC
`apiPort`	REST API
`p2pPort`	P2P
`grpcWebPort`	gRPC-Web
`pprofPort`	pprof
`evmPort`	EVM JSON-RPC — only with `{ evm: true }`

// EVM-enabled chains (e.g. evmd) need the extra port:
const ports = await findFreePorts({ evm: true });
const chain = Instance.evmd({ ...ports });

Don't hardcode URLs afterwards — the instance exposes them: instance.rpcUrl, instance.grpcUrl, instance.apiUrl, and instance.evmUrl on EVM chains.