Minting Your First Token

Now that you've completed the previous walkthrough you should have created your first contract. Now it's time to mint your first token. The term mint in this case means to create a new entry within our contract (token) that represents and is potentially tied to another asset, either digital or tangible.

Minting a token

Start by going to and selecting your crate. Once on the crate detail screen you should see the contract you created in the previous walkthrough. Click the Mint button and the mint popup will appear. I will explain each section:

Upload digital asset(s) - This is where you can upload files that will be associated with the token you are about to mint. For example, maybe I am minting a token that is tied to a buried treasure map. This is where I would upload to actual map file. The person that owns this token, and only that person, will be able to download the map that I upload. You can upload multiple files. You can drag and drop files from your computer, or you can click the Upload text.

Send to myself checkbox - The address above this checkbox will be automatically pre-populated to be your address. If you want this token to be sent to a different address when it is minted you can uncheck this checkbox and enter the address in the input field.

Name - This is the name of your token.

Description - This is the description of what this token is representing.

Additional optional metadata - For advanced use cases you may want to tie additional metadata to your token. ERC-721 tokens have an optional metadata extension* that Cargo uses to specify the name, description, and a preview image. We've also included and additional metadata field that can be used to specify any arbitrary data for your token. You can use the JSON editor provided, or you can manually enter valid JSON by clicking the I'd like to paste JSON checkbox.

Batch mint - This only applies to Cargo Batch Mint ERC-721 contracts. Select this checkbox if you wish to create many tokens at one time. These tokens will share the same metadata, but each will have a unique "edition" field. You will be able to enter how many tokens you'd like to mint after checking the box.

Preview Image - You can upload a preview image that can be used on your website, or that will be automatically shown when you create a Crate Page. There is a 350kb size limit for the preview images.

Once you have filled in the information click the blue "Mint" button. You will see two MetaMask popups when you mint a token. The second may take a moment to appear depending on how big the files your are.

Two things happen when you are minting a token. First, Cargo will ask you for your signature verifying you are who you say you are. That signature is sent to the Cargo backend servers along with the files and information related to your token. Cargo does some magic on the backend and then sends transaction information back to you. You will then see a second MetaMask popup where you can confirm the transaction. When your transaction is confirmed you will see your new token listed below your contract in the crate detail page! If you sent the token to yourself you will also see it in the "My Assets" tab.

*Information about ERC-721, including the metadata extension, can be found here.