> ## Documentation Index
> Fetch the complete documentation index at: https://docs.allium.so/llms.txt
> Use this file to discover all available pages before exploring further.

# ERC20, ERC721 And ERC1155 Tokens Coverage

> Coverage for ERC tokens decoding and we identify ERC tokens in our tokens decoding pipeline.

<Info>
  The ercX tokens tables only includes tokens decoded by the respective specifications. **The table does not include the universe of all ercX tokens deployed.**
</Info>

As part of our data pipeline, we decode contract deployments to identify ERC tokens. The decoded contracts generates the ercX tokens metadata (e.g. name, symbol, decimals).

Tokens that do not meet these specifications will not be decoded. We rely on a separate pipeline (RPC calls) to fetch the metadata.

| ERC Metadata Source | Caveats                                                                          |
| ------------------- | -------------------------------------------------------------------------------- |
| Decoding Pipeline   | Only includes tokens that meet the specification listed below.                   |
| RPC Contract Call   | These tokens will have null `block_timestamp`, `block_hash`, and `block_number`. |

## ERC-20 Token

An ERC-20 token is either

* a contract fulfilling the ERC-20 specifications ([https://eips.ethereum.org/EIPS/eip-20#methods](https://eips.ethereum.org/EIPS/eip-20#methods)), or

* a proxy contract in which its implementation points to a ERC-20 token. We currently support these proxy contracts:

  * `TransparentUpgradableProxy` [https://docs.openzeppelin.com/contracts/3.x/api/proxy#TransparentUpgradeableProxy](https://docs.openzeppelin.com/contracts/3.x/api/proxy#TransparentUpgradeableProxy)

## ERC-721 Token

Similarly, an ERC-721 token is either

* a contract fulfilling the ERC-721 specifications ([https://eips.ethereum.org/EIPS/eip-721#specification](https://eips.ethereum.org/EIPS/eip-721#specification)), or

* a proxy contract, defined as per above, in which its implementation points to a ERC-721 tokens.

## ERC-1155 Token

Similarly, an ERC-1155 token is either

* a contract fulfilling the ERC-1155 specifications ([https://eips.ethereum.org/EIPS/eip-1155#specification](https://eips.ethereum.org/EIPS/eip-1155#specification)), or

* a proxy contract, defined as per above, in which its implementation points to a ERC-1155 tokens.