chains

Built-in presets

Name	Chain ID
Ethereum	1
Base	8453
Polygon	137
BNB	56
Arbitrum	42161
Payy Testnet	7298
Payy Dev	7297
Sepolia	11155111
Hardhat	1337

The mainnet and testnet presets default to public RPC endpoints that do not require an API key. Override per command with --rpc, or persist a different default with beam rpc use.

Select a chain

By name or by chain id:

$ beam --chain base balance
$ beam --chain 8453 balance

List chains

$ beam chains list

Shows every configured chain (built-in + custom), the active default, and whether each chain has a privacy profile.

Set the default

$ beam chains use base

Persists the selection to ~/.beam/config.json. Use selectors like aliases (eth, bsc, arb, payydev) or numeric chain ids.

Add a custom chain

$ beam chains add "Beam Dev" https://beam.example/dev \
  --chain-id 31337 \
  --native-symbol BEAM

$ beam chains add "Private Dev" https://beam.example/dev \
  --chain-id 31337 \
  --native-symbol BEAM \
  --privacy-bridge 0x3100000000000000000000000000000000000000 \
  --privacy-features all

Omit the chain name or RPC URL to be prompted interactively. When --chain-id is omitted, Beam reads the chain id from the RPC before saving. When --chain-id is provided, Beam verifies the RPC reports the same id before persisting.

Custom names are trimmed, sanitized for terminal control characters, and rejected if they collide with an existing selector (including built-in aliases or numeric ids).

Remove a chain

$ beam chains remove "Beam Dev"

Privacy profiles

The --privacy-bridge and --privacy-features flags attach a privacy profile to the chain. A custom chain is privacy-capable only when its chain config carries a valid profile — Beam does not infer privacy support from an RPC endpoint alone.

The profile records the bridge contract, deployment kind, prover profile, token policy, state policy, and feature flags. See the privacy overview for what each flag enables.

Where it lives

• Built-in presets are compiled into the binary.
• Custom chain metadata is in ~/.beam/chains.json.
• Per-chain RPC config and the active default chain live in ~/.beam/config.json.