> For the complete documentation index, see [llms.txt](https://docs.mellow.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mellow.finance/core-vaults/architecture/libraries/slotlibrary.md).

# SlotLibrary

This library generates unique and collision-resistant storage slots for use in upgradeable Solidity contracts. It ensures that different modules or instances do not unintentionally overwrite each other’s storage, even when used via proxy or delegate calls.

### Storage Slot Strategy

* Based on EIP-7201
* Inputs include:
  * Contract name (`contractName`)
  * Human-readable name (`name`)
  * Version number (`version`)
* Final slot:

  ```solidity
  keccak256(
  	abi.encode(
  		uint256(
  			keccak256(
  				abi.encodePacked(
  					"mellow.flexible-vaults.storage.",
  					contractName,
  					name, version
  				)
  			)
  		) - 1
  	)
  ) & ~bytes32(uint256(0xff));
  ```

This structure ensures:

* **Namespacing:** Prevents overlap between different modules (`ShareModule`, `FeeManager`, etc.)
* **Instance separation:** Multiple deployments with different names produce distinct slots
* **Versioning:** Upgrades can cleanly migrate to new versions without collision

### Function

### `getSlot(string contractName, string name, uint256 version) → bytes32`

**Description:**

Computes a deterministic, collision-resistant storage slot for a contract module.

**Parameters:**

* `contractName`: Logical name of the module (e.g., `"ShareModule"`)
* `name`: Instance identifier or label (e.g., `"Mellow"`)
* `version`: Numeric version for versioned slot separation

**Returns:**

* A `bytes32` value representing the computed storage slot

**Example:**

```solidity
bytes32 slot = SlotLibrary.getSlot("FeeManager", "Mellow", 1);
```


---

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