Stake Beacon Chain (SBC)
Distributed community validation on xDai
Stake Beacon Chain (SBC) is currently in R&D. Targeting a Q4 soft launch for small-scale, distributed staking. A security audit has been completed and is available here.
‌The Stake Beacon Chain offers a new consensus opportunity for the xDai chain. It will start with modified client implementations (Prysm/Lighthouse) to support faster blocks and built for a wider community of diverse validators.
‌While the Eth 2.0 staking deposit contract has attracted an impressive number of validators (200K+), these validators must each contribute 32 ETH to participate. This amount is out of reach for many blockchain users. In addition, centralized exchanges are pooling funds to create largely connected staking pools which may limit overall decentralization.
The SBC is designed for users with small staking amounts who still want to participate as independent validators within an Ethereum-consistent and real-world value environment. It provides a similar experience and uses a similar methodology for validator set rotation to prevent collusion. With a lower-stakes chain, the amount staked can also be lower while providing security and protection through enhanced decentralization.

Proposed SBC Parameters

Required STAKE
Block times
5 seconds
Validator Slots per Epoch
Validators per slot
Epoch times
80 seconds
Repeated reductions to 16 STAKE then removal
Ongoing testing with Prysm and Lighthouse clients.
Custom Deposit Contract
  • ERC20-enabled deposits
  • Upgradeability
  • Claiming on accidental locks
  • Custom network keys generation (deposit-cli)
Modified version of
MVP for launch (pending system tolerance tests)
4096 validators 131,072 STAKE equivalent
83% APY
Security Goal Prior to Merge
50K+ validators
1.6M+ STAKE equivalent
23% APY
Validators with a small amount of STAKE (32 STAKE equivalent) will be able to stake and run a node through a simplified, step-by-step process.
‌STAKE will be locked in the contract and not available for immediate withdrawal, as is the case with the current Eth 2.0 deposit contract. Modifications to the deposit contract will enable ERC20 token deposits (STAKE) and additional upgradeability features.
STAKE will be deposited from the xDai side, significantly reducing transaction costs. Once active, stakers will receive a staking derivative which can be used to earn additional incentives on aligned DEXs within the xDai ecosystem.
The system will be designed to support 5 second blocks, significantly faster than the 12 second blocks on Eth 2.0. Slashing will also be incorporated in accordance with the Eth 2.0 contracts, where stakers will be slashed for incongruous behavior and deactivated once the 16 STAKE minimum threshold is reached for failure to properly run a node.
Early stakers will be incentivized by an APY of 80%+ for securing the chain. This incentive is quickly reduced as more validators onboard.
SBC will support all the same functionality and tools as Eth 2.0. While block times will slow slightly from the current 5 second model on xDai, blocks will be larger and over time rollups will provide the ability for additional transactional throughput and prioritization features.
Following the Eth1/Eth2 & xDai/SBC merges, a permissionless bridge structure (no relayers/validators) is planned since both chains will have the native capacity to validate one another's blocks.
Currently, the xDai chain is secured by ~640K STAKE by validators and their delegators. The goal is to match or exceed this amount. With 32 STAKE per validator, the system will require 20K+ validators to achieve the same level of security.
*ARP Calculator available here where the Y axis is APR and the X axis is the number of validators divided by 100 and shifted by 20 (2048 validators at point 0, 4096 validators at point ~20, 20'000 validators at ~180).
  • F - some block reward factor
  • T - time between blocks
  • S - amount of slots in an epoch
  • N - amount of validators required for the launch.

Technical Notes

Getting Started

Instructions are in development to include the following:


SBC will be supported by 2 clients and validators can choose which client they want to run. Note that validators will still need to operate or connect to an xDai node running Nethermind or OpenEthereum in addition to running the SBC client.
  • Lighthouse: A fast and secure client written in Rust
  • Prysm: A user-focused client with high reliability written in Go

SBC Repos

SBC Security Audit

Last modified 4d ago