PoS Validators
PoS (Proof of Stake) Validators are solo validators who secure Mosaic Chain by running validator nodes and producing blocks. They stake exclusively via their Validator NFT's nominal value and operate independently without accepting delegations.
What PoS Validators Do
PoS Validators are active participants in Mosaic Chain's consensus mechanism.
Core responsibilities:
✅ Run full validator nodes
✅ Produce new blocks (if selected by the subset algorithm)
✅ Validate transactions and maintain network security
✅ Stake via their Validator NFT's nominal value
✅ Earn block rewards and transaction fees
In Polkadot terms:
Mosaic validators are technically collators (they collect transactions and produce blocks for the Polkadot relay chain to finalize)
However, within Mosaic Chain's internal consensus, they function as validators
How Staking Works for PoS Validators
PoS Validators have a unique staking model:
Staking:
✅ Stake only via their Validator NFT's nominal value
❌ Cannot stake MOS coins
❌ Cannot accept delegations from others
Why this limitation?
PoS Validators are designed for solo operation
Simpler setup with no delegation management
Full control over their own stake and rewards
Requirements to Become a PoS Validator
To participate as a PoS Validator, you must:
Own and bind a PoS Validator NFT - Grants permission to validate and represents your stake
Run a validator node - Using Validator OS (plug-and-play system)
Maintain uptime - Keep your node online and synced 24/7
Be selected by the subset algorithm - ~200 validators are randomly selected each session (1 hour)
PoS Validator NFTs
The PoS Validator NFT represents both your permission to validate and your stake.
Key features:
Nominal value - The NFT's nominal value is your stake (subject to slashing)
Transferable - Can be sold or transferred to another account
Binding required - Must be bound to your account to participate
Unbinding conditions - Can only unbind if validator is chilled, not active, and the staking contract has ended
Your stake = Your NFT's nominal value
Unlike DPoS Validators who can add MOS coins to their stake, PoS Validators stake exclusively through their NFT's nominal value.
Rewards
PoS Validators earn rewards from two sources:
1. Block Rewards
Newly minted MOS coins (calculated via expansion formula)
Distributed at the end of each session to active validators
2. Transaction Fees
50% of transaction fees go to the block producer
100% of tips go to the block producer
40% of fees are burnt (removed from circulation)
10% of fees go to the Treasury
Reward distribution:
Rewards are distributed at the end of each session (1 hour ≈ 600 blocks)
Only active validators (selected for that session) earn rewards
PoS Validators keep 100% of their rewards (no commission sharing)
Slashing & Auto-Chilling
PoS Validators can be slashed for poor behavior or downtime.
Slashing
What gets slashed:
Validator NFT's nominal value (0.1% of nominal value per slashing event)
Slashing triggers:
Extended downtime
Double-signing blocks
Other malicious behavior
Auto-Chilling
Validators are automatically removed from the active set if:
Slashed in two consecutive sessions
Validator NFT's nominal value drops below 80% of its initial value
Recovery:
Validators can unchill manually
Validators must top up their NFT's nominal value to resume validation if it has dropped below 80% of its initial value
After topping up, they can rejoin the waiting set
Learn more:
DPoS Validators → - Compare with delegation-accepting validators
Delegators (Stakers) → - Learn about passive staking
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