# `@metamask/assets-controllers`

Controllers which manage interactions involving ERC-20, ERC-721, and ERC-1155 tokens (including NFTs).

## Installation

`yarn add @metamask/assets-controllers`

or

`npm install @metamask/assets-controllers`

## Controllers

This package features the following controllers:

- [**AccountTrackerController**](src/AccountTrackerController.ts) keeps a updated list of the accounts in the currently selected keychain which is updated automatically on a schedule or on demand.
- [**AssetsContractController**](src/AssetsContractController.ts) provides a set of convenience methods that use contracts to retrieve information about tokens, read token balances, and transfer tokens.
- [**CollectibleDetectionController**](src/CollectibleDetectionController.ts) keeps a periodically updated list of ERC-721 tokens assigned to the currently selected address.
- [**CollectiblesController**](src/CollectiblesController.ts) tracks ERC-721 and ERC-1155 tokens assigned to the currently selected address, using OpenSea to retrieve token information.
- [**CurrencyRateController**](src/CurrencyRateController.ts) keeps a periodically updated value of the exchange rate from the currently selected "native" currency to another (handling testnet tokens specially).
- [**TokenBalancesController**](src/TokenBalancesController.ts) keeps a periodically updated set of balances for the current set of ERC-20 tokens.
- [**TokenDetectionController**](src/TokenDetectionController.ts) keeps a periodically updated list of ERC-20 tokens assigned to the currently selected address.
- [**TokenListController**](src/TokenListController.ts) uses the MetaSwap API to keep a periodically updated list of known ERC-20 tokens along with their metadata.
- [**TokenRatesController**](src/TokenRatesController.ts) keeps a periodically updated list of exchange rates for known ERC-20 tokens relative to the currently selected native currency.
- [**TokensController**](src/TokensController.ts) stores the ERC-20 and ERC-721 tokens, along with their metadata, that are listed in the wallet under the currently selected address on the currently selected chain.

## Contributing

This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).