Protocol Architecture: How the Contracts Fit Together

stake.link uses the same core contracts for every liquid staking token (stLINK, stPOL, stESP). Each network has its own strategy and vault contracts that connect the core to that network’s native staking.

Deposit flow

 User deposits LINK / POL / ESP
            │
            ▼
   ┌─────────────────┐   queue, reSDL priority, liquidity buffer
   │  PriorityPool   │
   └────────┬────────┘
            ▼
   ┌─────────────────┐   mints rebasing LST (stLINK, stPOL, stESP) 1:1
   │   StakingPool   │◄── RebaseController triggers reward rebases
   └────────┬────────┘
            ▼
   ┌─────────────────┐   OperatorVCS + CommunityVCS (LINK),
   │    Strategies   │   PolygonStrategy (POL), EspressoStrategy (ESP)
   └────────┬────────┘◄── fund flow controllers manage unbonding
            ▼
   ┌─────────────────┐   hold the staked positions
   │     Vaults      │
   └────────┬────────┘
            ▼
   Native staking contracts (Chainlink Staking, Polygon, Espresso)

1. Queue. Users deposit tokens into the PriorityPool. When the network has staking capacity, queued tokens are deposited into the StakingPool. Wallets holding reSDL are served first.
2. Mint. The StakingPool mints a rebasing liquid staking token at 1:1 and deposits the tokens into one or more strategies.
3. Stake. Each strategy spreads deposits across vaults, and each vault stakes in the network’s native staking contract.
4. Earn. The RebaseController triggers rebases that add rewards to every holder’s balance, minus protocol fees.

Withdrawal flow

When a user redeems an LST, the PriorityPool first swaps it for tokens waiting in the queue. Next, if instant withdrawals are enabled, it pays out tokens that are already withdrawable from the StakingPool. The rest is queued in the WithdrawalPool and paid out as new deposits arrive or as vaults finish unbonding. See How withdrawals work.

Rewards and SDL

• Users stake SDL (StakingAllowance) in the SDLPool and receive reSDL NFTs. The LinearBoostController calculates the boost for locked positions.
• The SDL stakers’ share of protocol fees, paid in LSTs, is distributed to reSDL holders through RewardsPool contracts. RewardsPoolWSD handles rebasing reward tokens by wrapping them.

Contracts by role

Role	Contracts
Core (shared by all LSTs)	StakingPool, PriorityPool, WithdrawalPool, RebaseController
Tokens	StakingAllowance (SDL), WrappedSDToken (wstLINK, wstPOL, wstESP)
SDL and rewards	SDLPool, LinearBoostController, RewardsPool, RewardsPoolWSD
LINK staking	OperatorVCS, OperatorVault, CommunityVCS, CommunityVault, FundFlowController, OperatorStakingPool
POL staking	PolygonStrategy, PolygonVault, PolygonFundFlowController
ESP staking	EspressoStrategy, EspressoVault, EspressoFundFlowController
Rewards splitting	LSTRewardsSplitterController, LSTRewardsSplitter

LINK staking specifics

stake.link stakes LINK in both Chainlink staking pools:

• Node Operator Pool: OperatorVCS manages one OperatorVault per node operator. Node operators stake their own LSTs in the OperatorStakingPool, which keeps their balances separate from community stakers.
• Community Pool: CommunityVCS manages many CommunityVault contracts.
• Unbonding: the FundFlowController decides the order of vault deposits and withdrawals, and unbonds vaults periodically so LINK is always available to withdraw.

Source code and addresses

• Source code: github.com/stakedotlink/contracts
• Deployed addresses: Smart contract addresses
• Audits: Security and audits
• On-chain data: Subgraph (GraphQL API)