Inscriptions

Inscriptions on EVM chains are arbitrary data written into the chain's history using the calldata field. Because the data is only stored in the chain's history, and not within state itself, it lowers the cost of sending data to the chain.

However, because the data is not actually stored in state, it is impossible to use the data from within smart contracts. This means that inscriptions are only useful for indexing and other off-chain purposes until the data is written into state.

Gas fees, throughput, and inscriptions

On the majority of other EVM supporting chains, inscriptions has caused massive upward pressure on gas fees, as well as degradation of throughput. However, on EOS EVM the gas fee is fixed, and the chain is more than capable of handling the load of inscriptions without any noticeable impact on throughput.

Want to test inscriptions?

Each section here has a form you can use to trigger a MetaMask transaction with the inscription data. If you want to use them, you'll need to login with MetaMask first.

The inscription format

Inscriptions are a simple JSON format that can be embedded in the call data of a transaction. The format must be adhered to or third party tooling like indexers will not be able to process the data.

✔ You can add other fields

You are free to add fields to the JSON object that your specific project might benefit from, but every field below is required.

{
  "p": "eorc-20",
  "op": "deploy",
  "tick": "orcs"
}

Key	Description
p	The protocol helps tooling identify and process events
op	The operation type: deploy, mint, transfer, list
tick	The token ticker

Deploy

{ 
  "p": "eorc-20",
  "op": "deploy",
  "tick": "orcs",
  "max": "420420",
  "lim": "69"
}

Key	Description
max	The maximum supply of the token
lim	The mint limit per inscription

Mint

{ 
  "p": "eorc-20",
  "op": "mint",
  "tick": "orcs",
  "amt": "69"
}

Key	Description
amt	The amount to mint

Transfer

{ 
  "p": "eorc-20",
  "op": "transfer",
  "tick": "orcs",
  "amt": "1"
}

Key	Description
amt	The amount to transfer

Sending inscriptions

When sending inscriptions to the chain you must specify the mime-type of the data, or leave it as data:, so that it defaults to text/plain.

For example:

data:,{"p":"eorc-20","op":"deploy","tick":"orcs","max":"420420","lim":"69"}

Then, you must convert the JSON to hex and use the data field of the transaction to send the inscription.

An example of this using ethers would be:

const { ethers } = require('ethers');
const provider = new ethers.providers.JsonRpcProvider('https://api.evm.eosnetwork.com/');
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);

const json = {
    p: 'eorc-20',
    op: 'deploy',
    tick: 'orcs',
    max: '420420',
    lim: '69',
};

const utfBytes = ethers.utils.toUtf8Bytes(JSON.stringify(json));
const hexData = ethers.utils.hexlify(utfBytes);

const tx = {
    to: '0x123...',
    value: 0,
    data: hexData
};

wallet.sendTransaction(tx).then(...);

Rules you need to know

Indexers have built-in rules that they must abide by when indexing inscriptions. Any inscription that does not follow these rules will be ignored.

Owners / signers

• The mint receiver is the signer of the transaction
• The transfer sender (or from) is the signer of the transaction
• The transfer receiver is the to address defined in the transaction data

General rules

• The first deployment of a ticker is the only one that has claim to the ticker
• Tickers are not case sensitive (orcs = ORCS = OrCs ...)
• The last inscription of a ticker will get either the specified amount or what is left over of the max supply
• Maximum supply cannot exceed the maximum value of uint64