Operational Terms

This page is a work in progress as implementation details are ongoing

Active Stake

Stake currently in use by the validator set is called active stake. The amount of active stake is snapshotted at the beginning of each staking epoch and used as the basis for reward distribution among validator pools at the end of the epoch.

Additional stake can be placed on validator pools during a staking epoch, however, this is pending stake and does not impact the pool until the next staking epoch. Active stake cannot be withdrawn or moved during a staking epoch, but it can be ordered for withdrawal (the withdrawal amount can be claimed beginning with the next staking epoch).


The balance is the amount of STAKE available on a participant’s address connected by a web3 browser extension (like MetaMask or NiftyWallet). The available balance, along with the current staked amount, is displayed below the connected address in the UI. If STAKE is acquired on the Ethereum mainnet through an exchange, crowdsale, or other means, it must be converted to xDai STAKE using the bridge before it can be used for staking on the xDai Stable Chain.


A ban occurs due to validator misbehavior. This can include:

  • not revealing a secret number more than 55 times in a staking epoch

  • not revealing a secret number on the last reveal round of a staking epoch

  • reported malicious behavior (ie releasing 2 blocks at the same step or releasing a block out of order) by other validators

  • too many calls to the reportMalicious function (spam calls)

When a validator is banned, they are immediately removed from the current staking epoch and moved to the inactive pool list. They do not receive any rewards from the staking epoch. Rewards are distributed among the remaining validators in the set at the end of the staking epoch.

Any funds in the pool (validator and delegator stakes) are frozen for a period of 90 days. During that time, the mining address of the banned validator is prevented from participating in an active pool. At the end of 90 days, the funds are released and can be withdrawn or moved to another pool, and the ban is lifted.

To reactivate a banned pool after the 90 day ban is complete, a candidate must increase their stake by any amount, as long as the total amount is equal to the minimum candidate stake requirements. Adding stake calls the stake function and reinstates the pool.

Block number

Each block in the chain is numbered sequentially starting from the genesis block. The block number displayed in the BlockScout interface corresponds to block height; it is the most current block in the chain.

Claim Reward

Block rewards are distributed at the end of each staking epoch, but these distributions must be claimed by validators and delegators active during that epoch. The manual claiming process transfers the participant's reward from the contract to each participant's individual wallet. Validators must use their staking address to claim, and delegators must use their delegation address. Users can specify claims for specific staking epochs or claim rewards for all past staking epochs.

Claim Ordered Withdrawal

Stake ordered for withdrawal is available to claim once the staking epoch in which the claim was ordered is complete. To claim an ordered withdrawal, simply click on the Withdraw/Claim button and claim the ordered amount from the popup window. The claim will be processed through a web3 connected wallet, and will require a minimal amount of xDai to complete the transaction.

Minimum Stake

A pool must contain at least the minimum amount of stake from a candidate in order to become active. Minimum stake requirements exist for validator candidates as well as for delegators. The minimum stake amount for delegators is much lower.

  • For validator candidates, the minimum stake is 20000 STAKE.

  • For delegators, the minimum stake is 1000 STAKE per candidate. Stake may be placed on multiple candidates, but at least 1000 STAKE must be placed on each candidate/validator.

If a candidate tries to place an amount of stake that does not meet the minimum stake requirements, their pool is not created.

Mining Address

The mining address is used by a validator’s node to sign blocks, participate in the randomness beacon, and report on any malicious validators. Mining addresses have the ability to call certain functions using a zero gas price. This address must be configured on the node and provided to the interface when becoming a candidate.

To start, generate a new Ethereum address and corresponding private key using tools such as MyCrypto, Metamask etc. Create a new account and export and save the private key.

Next, follow the instructions for setting up a new xDai node. You will provide the mining address and JSON keystore password during node setup.

Once your node is ready, you can become a candidate through the web UI. You will enter in the node’s mining address during this process.

Move Stake

Delegators and candidates can move stake between different candidate pools. Stake can be moved from active or inactive candidate pools at any time. If stake was placed on a current validator during the current staking epoch, it is pending stake and may be moved. However, stake placed on a current validator during a previous epoch is currently in use (active stake), and cannot be moved. To reallocate active stake, follow the order a withdrawal process.

To move, click on the move stake icon associated with the pool where the stake is placed. A pop-up will present information about the current amount staked in the pool and a dropdown list of pools where the stake may be moved. Select the amount to move and the pool you would like to move the stake to. That pool’s information will populate in the modal. Click the move stake button to confirm the move. A transaction will be registered in your web3 wallet (metamask etc.) and stake will be moved to the new pool.

Order Withdrawal

Active stake cannot be immediately withdrawn by a delegator or validator from a validator pool, however, an order may be placed to withdraw this stake. Once the epoch is complete, the ordered amount is available to be claimed.

To order a withdrawal, click on the withdraw icon associated with the validator pool you would like to withdraw from. The withdraw popup will appear. Enter the withdrawal order amount.

If this is an active validator, the Withdraw Now button will be inactive, and the Order Withdrawal button will be active. Click the Order Withdrawal button to complete the order.

If an order for withdrawal has already been placed during the current staking epoch, it is possible to update this order using the same interface. Entering an additional positive amount will increase the order withdrawal, and entering a negative amount will decrease the order accordingly. Withdrawal orders can be claimed once the current staking epoch is complete and a new staking epoch begins.

Pending Stake

Pending stake is stake placed during the current staking epoch which is not yet activated. It does not impact the current staking epoch. Pending stake can be moved, increased, or withdrawn during the staking window. Once the window is closed, any placed stake is frozen until the next staking epoch begins.

Remove My Pool

The Remove My Pool function removes a pool from selection consideration for the next staking epoch. It moves candidate's/validator's active pool to the inactive pools list, and ensures that a current validator pool completes the current staking epoch but does not participate in new validator set selection at the end of the epoch.

The Remove My Pool link appears in the header (instead of the become a candidate button) when the application is accessed using an associated staking address. Clicking on this link will initiate the transaction to move the pool to the inactives list. All staked funds will remain in the pool during this process.

Stake, Staked

Stake is an amount of STAKE tokens deposited into the protocol by validators, candidates, and delegators. Stake protects the protocol and promotes honest behavior; users who provide stake do not want to lose this stake or potential rewards due to malicious behavior (See banning for details and consequences related to malicious behavior). The total stake amount in a pool influences the likelihood of that pool’s selection to a validator set. The more stake contained in a candidate’s pool, the higher their probability of selection to a validator set.

Contrary to many Proof of Stake implementations, total pool stake amounts do not correspond to higher validator rewards in the POSDAO protocol. Each validator pool within a validator set receives the same reward for participating in consensus and securing the chain. However, staking percentages do impact distribution within each pool, as the amount of stake provided by delegators determines the amount of reward the validator and each of their delegators receive.

Stake is managed according to the following rules:

  • Stake can be placed, moved, or withdrawn (or ordered for withdrawal) during the staking window, which begins immediately after the staking epoch starts, and ends ~6 hours (4332 blocks) prior to the end of the staking epoch. No staking actions can take place outside of the staking window.

  • Stake can be freely placed, moved, or withdrawn from candidate pools during a staking epoch.

  • Stake may be placed on a current validator pool, however it will not impact current pool rewards or staking percentages until the following staking epoch. In this case, it is referred to as pending stake.

  • Pending stake may be moved or withdrawn during the staking window.

  • Active stake placed in a validator pool may be ordered for withdrawal. When the staking epoch is complete, this ordered amount may be claimed.

Staking Address

The Ethereum address related to a candidate or validator and used to place stakes and collect rewards. The staking address is tied to the mining address when completing the Become a Candidate process.

A staking address is generated just like any other arbitrary Ethereum address. Ecosystem tools such as MetaMask or MyCrypto provide easy interfaces for address and private key creation. Staking addresses must be funded with enough STAKE to provide at least the minimum staking amount, and a small amount of xDai to cover transaction fees.

Staking Window

The period of time when stake may be placed on or withdrawn/ordered from a candidate or validator pool. The staking window begins shortly after a staking epoch starts, and ends during the final ~6 hours of a staking epoch. During the disallow period (when the window is closed), stake may not be withdrawn, placed, or ordered preventing manipulation of the incoming validator set at the end of an epoch.

Stakes Ratio

The Stakes Ratio shows the amount of stake deposited in a validator’s pool relative to the total stake committed to all validator pools. For example, if the total staked amount for all validator pools is 30000, and the staked amount in a specified validator’s pool is 5000, the Stakes Ratio for this pool is 16.67%. A higher stakes ratio corresponds to a greater likelihood of selection to the next validator set (when there are more than 19 candidates).