# Stake

Staking into a Rewards Manager, provides users with the opportunity to earn rewards. Different stake pools will have a different underlying stake asset and provide a different reward profile.

Stakers receive receipt tokens, which can be used to claim rewards.

### Using CozyRouter to stake assets

The recommended way to programmatically stake assets is to call `CozyRouter.stake` (see [CozyRouter](https://csm-docs.cozy.finance/developer-guides/stake-into-a-rewards-manager/broken-reference)):

```solidity
function stake(IRewardsManager rewardsManager_, uint16 stakePoolId_, uint256 stakeAssetAmount_, address receiver_)
    external
    payable
    returns (uint256 stakeReceiptTokenAmount_);
```

This method will:

* Transfer the underlying stake assets from the `msg.sender` to the Rewards Manager.
* Internally call `RewardsManager.stakeWithoutTransfer.` 

Prior to calling this function, the user must have approved `CozyRouter` to a spend sufficient amount of their `StakePool.asset` balance.

### Stake mechanics

`RewardsManager.stakeWithoutTransfer` assumes that the assets to be stakes have already been transferred to the Rewards Manager. Any excess assets transferred will be kept by the Rewards Manager. 

On stake, we follow the following steps:

* Check it the Rewards Manager is `PAUSED`. If so, revert.
* Check the Rewards Manager's asset balance to determine if the stake amount was transferred. If not, revert.
* Update the `StakePool.amount` value.
* Drip and apply any pending rewards to get `claimableRewards[stakePoolId_]` up to date.
* Update `userRewards[stakePoolId_][receiver_]`.
* Mint the `receiver_` address stake receipt tokens.
* Emit a `Staked` event.