The nxm-rs fork of a16z/helios — an in-process Ethereum light client that converts an untrusted centralised RPC into an unmanipulable local one by independently verifying every value against beacon-chain sync-committee signatures.

This fork exists because the Nexum wallet embeds Helios directly and needs a few changes not yet upstream:

• jsonrpc-server made a feature flag so library consumers don't pull the binary stack (#12)
• reqwest defaults trimmed (no charset, no system proxy) — meaningful binary-size win on mobile (#14)
• opstack libp2p bump cherry-picked ahead of upstream (#10)

We track upstream master and intend to upstream changes where they make sense. Use this fork if you're embedding Helios inside Nexum or another constrained mobile/WASM target; use upstream for the standalone CLI.

Looking for the org overview? See github.com/nxm-rs.

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Build from source

git clone https://github.com/nxm-rs/helios
cd helios
cargo build --release

Binary lands at target/release/helios. Run against Ethereum mainnet:

helios ethereum --execution-rpc $ETH_RPC_URL

$ETH_RPC_URL must support eth_getProof (Alchemy, Infura, etc.). Helios exposes a local verified RPC at http://127.0.0.1:8545.

Supported chains in this workspace: Ethereum mainnet, OP Stack (op-mainnet, Base), Linea. Upstream usage docs (installer, CLI flags, RPC method support) apply unchanged — see docs/ and rpc.md.

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Embedding

The Nexum mobile wallet depends on helios-ethereum, helios-common, and helios-core from this fork directly, rather than the helios meta-crate (which transitively pulls helios-opstack's libp2p stack — a yanked core2 0.4.0 in 0.11.1). Do the same in any no-libp2p setting (mobile, WASM).

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Contributing

This fork is intentionally small. Net-new features should go upstream first; this repo carries downstream patches and pre-upstream cherry-picks. Open chain-protocol or general improvements against a16z/helios. Conventional Commits. PR descriptions should state whether the change is intended to go upstream.

Security

See SECURITY.md. Helios-specific findings (sync-committee verification, proof handling, fork detection) via GitHub Security Advisories on this repo; findings in unchanged upstream code should also be disclosed to a16z.

License

MIT — inherited from upstream. See LICENSE.

●  fork of a16z/helios  ·  embeddable in mobile/WASM  ·  upstream-track