NFTs

Chainlens Blockchain Explorer has full Non-fungible Token Support

Chainlens supports two types of NFT token. Those that support the original ERC-721 standard, and those that support the ERC-1155 multi-token standard.

You can access the NFT view in Chainlens by clicking the navigation item.

Chainlens NFT Explorer Navigation Menu
Chainlens NFT Explorer Navigation Menu

Common issues with NFTs

In order for NFTs to be rendered correctly in Chainlens, there are a few details that the creators need to get correct. Chainlens helps creators understand where the errors lies in the event that NFTs are not deployed correctly on the network.

Clicking this link takes you to the listing page for all NFTs.

Chainlens NFT Explorer See all NFTs on the listing page

From here you can click on a specific NFT and view information the collection its from.

Chainlens NFT Explorer the Collections tab displays the NFTs in the collection

If you click on a specific NFT you see information about it including its name, image, description and any attributes.

Chainlens NFT Explorer shows detailed NFT attributes
An NFT with a large number of attributes

Additionally, we recognise that sometimes information is missing from NFTs preventing from them rendering correctly in explorers. To address this we've added additional information in Chainlens for users.

To unpack this, its helpful to discuss how NFTs are implemented on Ethereum networks.

Components of an NFT

NFTs are created by smart contracts implementing the ERC-721 or ERC-1155 standards.

ERC-721 is the original NFT standard. ERC-1155 came along later adding the ability to use a single smart contract for managing multiple collections of fungible and non-fungible tokens.

You'll see both types of tokens in Chainlens, where ERC-721 tokens are labelled Non-Fungible, whereas ERC-1155 are labelled Hybrid.

Chainlens NFT Explorer An ERC-721 NFT labelled Non-Fungible
An ERC-721 NFT labelled Non-Fungible
Chainlens NFT Explorer An ERC-1155 NFT labelled Hybrid
An ERC-1155 NFT labelled Hybrid

NFT Metadata

Both standards contain an optional metadata extension which is used to provide information about the assets contained by NFTs.

These interfaces are below.

ERC-721 Metadata Interface


interface ERC721Metadata /* is ERC721 */ {
    /// @notice A descriptive name for a collection of NFTs in this contract
    function name() external view returns (string _name);

    /// @notice An abbreviated name for NFTs in this contract
    function symbol() external view returns (string _symbol);

    /// @notice A distinct Uniform Resource Identifier (URI) for a given asset.
    /// @dev Throws if `_tokenId` is not a valid NFT. URIs are defined in RFC
    ///  3986. The URI may point to a JSON file that conforms to the "ERC721
    ///  Metadata JSON Schema".
    function tokenURI(uint256 _tokenId) external view returns (string);
}

ERC-1155 Metadata Interface


interface ERC1155Metadata_URI {
    /**
        @notice A distinct Uniform Resource Identifier (URI) for a given token.
        @dev URIs are defined in RFC 3986.
        The URI MUST point to a JSON file that conforms to the "ERC-1155 Metadata URI JSON Schema".       
        @return URI string
    */
    function uri(uint256 _id) external view returns (string memory);
}

This metadata extension, named tokenURI(uint256 _tokenId) and function uri(uint256 _id) in ERC-721 and ERC-1155 contracts respectively returns a URI string which can be used to obtain additional data about an NFT encoded in JSON.

This URI string will usually resolve to a URL. The URL is often hosted on the decentralised IPFS network, but it could be a location on a traditional storage location, such as an AWS S3 bucket.

The format of the JSON schemas is as per the below.

ERC-721 URI schema


{
    "title": "Asset Metadata",
    "type": "object",
    "properties": {
        "name": {
            "type": "string",
            "description": "Identifies the asset to which this NFT represents"
        },
        "description": {
            "type": "string",
            "description": "Describes the asset to which this NFT represents"
        },
        "image": {
            "type": "string",
            "description": "A URI pointing to a resource with mime type image/* representing the asset to which this NFT represents. Consider making any images at a width between 320 and 1080 pixels and aspect ratio between 1.91:1 and 4:5 inclusive."
        }
    }
}

ERC-1155 URI schema


{
    "title": "Token Metadata",
    "type": "object",
    "properties": {
        "name": {
            "type": "string",
            "description": "Identifies the asset to which this token represents"
        },
        "decimals": {
            "type": "integer",
            "description": "The number of decimal places that the token amount should display - e.g. 18, means to divide the token amount by 1000000000000000000 to get its user representation."
        },
        "description": {
            "type": "string",
            "description": "Describes the asset to which this token represents"
        },
        "image": {
            "type": "string",
            "description": "A URI pointing to a resource with mime type image/* representing the asset to which this token represents. Consider making any images at a width between 320 and 1080 pixels and aspect ratio between 1.91:1 and 4:5 inclusive."
        },
        "properties": {
            "type": "object",
            "description": "Arbitrary properties. Values may be strings, numbers, object or arrays."
        }
    }
}

Correct NFT Deployment

When NFTs are minted on a network, for them to render correctly, they all need to be present in the smart contract creating the NFTs:

  • Lookup by token id returns a metadata URI
  • The metadata URI is accessible
  • The metadata URI contains an image URI property
  • This image URI is accessible and contains a valid image format

If any of the above steps fail then an NFT will not render correctly.

Given the series of stages required to render NFTs correctly, Chainlens now makes it clear where the problems lie when NFTs aren't being rendered correctly.

Digging Deeper into NFTs in Chainlens Blockchain Explorer

When you navigate to an NFT collection page, the Collections tab displays the NFTs in the collection. Provided the NFT has been deployed correctly you will see preview images for individual NFTs in the collection.

Chainlens NFT Explorer NFT Collection Details

Clicking on one of the NFTs will show you information about that specific NFT. In the below example, we have the name, NFT type, address, metadata URL and attributes.

Chainlens NFT Explorer NFT details

If you click on the metadata URL hyperlink you will be able to see the metadata associated with the NFT.

In this instance, it's hosted on IPFS.

Chainlens NFT Explorer lets you see the metadata associated with the NFT.

If there are any issues with the rendering of the NFT, it's straightforward to see where the problem lies.

  • If there is no metadata for the token, the metadata URL will be blank
  • If the metadata URL is not accessible, a No Metadata image is displayed
  • If the image URI is not accessible, a blank image is displayed
Chainlens NFT Explorer icon when An NFT does not have metadata
An NFT without metadata

Frequently asked questions

What is a Blockchain Explorer as a Service?

A Blockchain Explorer as a Service (EaaS) provides a fully managed blockchain explorer for your network and its users, without the need for local infrastructure setup.

How does Chainlens benefit developers working on EVM blockchains?

Chainlens enhances productivity for developers allowing them to see on-chain activity associated with their contracts. with advanced tools for data analysis, contract testing, and seamless integration with existing EVM and Ethereum standards.

What kind of blockchain data and insights can I access through Chainlens?

Chainlens provides a number of types of data —enriched blockchain data on on-chain asset such as NFTs and tokens as well as user balances associated with them. It also provides decoded smart contract data and metadata associated with NFTs. Raw blockchain data such as block information and transaction details are also included. Comprehensive analytical data is also collected for many types of data.

Can Chainlens help me track my NFTs on EVM blockchains?

Yes, Chainlens provides comprehensive NFT support, allowing you to view NFTs that are contained within specific wallets, or browse entire collections on EVM blockchains. It also provides a breakdown of attributes associated with specific NFTs.

Does Chainlens offer any analytics or reporting capabilities?

Chainlens includes comprehensive analytics and reporting features that provide deep insights into both historical and current blockchain activity and trends for networks.

What kind of documentation and support is available for Chainlens?

Chainlens offers detailed documentation and responsive customer support to assist users with issues when they occur.

Can Chainlens scale to meet the needs of large or high-traffic networks?

Yes, Chainlens is designed to scale efficiently as networks grow, both in terms of handling greater volumes of user traffic, as well as supporting large volumes of network transactions.

Does Chainlens stay updated with the latest network developments and updates?

Chainlens continually updates its services to cater for upgrades and enhancements made to network protocols. 

What features and tools does Chainlens offer?

Chainlens offers customizable branding, powerful search, sleek dashboards, a complete API for integrations, and great support for NFTs and tokens. It also provides high-quality decoded blockchain data for network operators, developers and end-users.

Is Chainlens compatible with existing Ethereum tools and standards?

Yes, Chainlens supports the EIP-3091 standard for block explorer API allowing it to seamlessly  integrate with existing Ethereum tools such as wallets. It also supports contract verification via the Sourcify service.

How does Chainlens handle smart contract interaction and verification?

Chainlens supports direct interaction with verified contracts. Verified contracts are those that have been verified using the Sourcify service. This can be done directly from Chainlens when viewing the details of a smart contract or directly via the Sourcify service.

What are the advantages of using Chainlens over building my own blockchain exploration tools?

Using Chainlens saves time and resources so your team can focus on their core competencies. Using Chainlens managed service offers significant cost savings over running your explorer infrastructure yourself, offering a ready-to-use, scalable, and platform for blockchain exploration and analytics to serve both your team and community.

How easy is it to integrate Chainlens into my existing projects or workflows?

Integration is streamlined and user-friendly via Chainlens powerful API. which has extensive documentation to guide users through the process.

Are there any pricing plans or subscription options for Chainlens?

Chainlens provides flexible pricing plans tailored to the needs of different networks, from new networks with only a few thousand transactions up to large established networks with tens or hundreds of millions of transactions.

How secure and reliable is the infrastructure behind Chainlens?

Chainlens uses robust security measures and reliable cloud based infrastructure providers to ensure safe and uninterrupted service.

Can Chainlens assist with smart contract deployment and management?

The deployment process is usually driven by developers. However, Chainlens complements this by providing tools for verifying and working with deployed smart contracts efficiently.

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