> For the complete documentation index, see [llms.txt](https://docs-v4.nftx.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-v4.nftx.io/core-concepts/vaults.md).

# Vaults

A **vault** is the container at the heart of every NFTX collection. It holds the deposited NFTs from a single collection and issues a fungible [floor token](/how-it-works/floor-tokens.md) against them — one token for each NFT it holds. Everything else in NFTX (listings, swaps, trade-ups) is built on top of this one primitive.

On-chain, the vault is the [Locker](/contracts/locker.md) contract.

## One collection, one vault

Each vault is tied to a **single ERC-721 collection**, and each supported collection has one vault. Deposit a Milady and you're depositing into the Milady vault, which mints MILADY tokens; you can't deposit a different collection's NFT into it. This is what keeps a floor token cleanly backed: every MILADY in circulation corresponds to exactly one Milady sitting in the vault.

## Eligibility

A vault accepts the NFTs of its collection. Which token IDs qualify as floor items — and any rules a collection sets around what it will hold — are part of the vault's configuration. Rare or non-floor items aren't excluded; they're handled through [Liquid Listings](/how-it-works/liquid-listings.md), which price them above floor rather than treating them as a plain floor deposit.

## Lifecycle

A vault moves through a simple lifecycle:

1. **Creation.** A collection is launched onto NFTX, creating its vault and floor token. Who can do this is set by the collection's launch gate — see [Collection Lifecycle](/how-it-works/collection-lifecycle.md).
2. **Active.** NFTs are deposited and redeemed, listings are created and filled, and the floor token trades against ETH in the collection's Uniswap V4 pool.
3. **Shutdown (if needed).** If a collection becomes illiquid, holders can vote to wind it down and distribute the remaining value — also covered in [Collection Lifecycle](/how-it-works/collection-lifecycle.md).

## Non-custodial and non-upgradeable

The vault never takes custody in the traditional sense — your NFT is held by an immutable contract, not a company, and you can redeem an equivalent NFT at any time by returning a floor token. The contracts are **non-upgradeable**: the deployed logic can't be swapped out from under you. As with any protocol, that doesn't remove risk — even audited code can contain bugs — but it does mean the rules you deposit under are the rules that stay in force.

For the full contract surface — `deposit`, `redeem`, `swap`, and collection creation — see the [Locker](/contracts/locker.md) reference.