# Nft Blockchain > NFT display and blockchain interaction in Decentraland. Use when the user wants NFTs, blockchain, wallet, smart contracts, Web3, or token gating. Do NOT use for player avatar data or emotes (see player-avatar). - Skill: `decentraland/nft-blockchain` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add decentraland/nft-blockchain` - Raw SKILL.md: https://api.skillmd.com/api/skills/decentraland/nft-blockchain/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: decentraland (https://skillmd.com/u/decentraland) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/decentraland/nft-blockchain --- # NFT and Blockchain in Decentraland ## Display NFT Artwork Use `NftShape` to show an NFT in a decorative picture frame. Provide the NFT URN and choose a frame style. The image is loaded automatically from the NFT's metadata (fetched through Decentraland's OpenSea proxy, `opensea.decentraland.org`) — any NFT that OpenSea supports can be displayed, across multiple chains. **NFT URN format:** `urn:decentraland::::` - Example: `urn:decentraland:ethereum:erc721:0x06012c8cf97bead5deae237070f9587f8e7a266d:558536` - `` supported values (forwarded verbatim to the OpenSea v2 API; unrecognized chains are rejected): `ethereum`, `matic`, `klaytn`, `bsc`, `arbitrum`, `arbitrum_nova`, `avalanche`, `optimism`, `solana`, `base`, `blast`, `zora`. - `` is typically `erc721`. The image is served from the OpenSea response, so contracts OpenSea indexes as `erc1155` also resolve. ### Available Frame Styles ```typescript NftFrameType.NFT_CLASSIC // Simple classic frame NftFrameType.NFT_BAROQUE_ORNAMENT // Ornate baroque NftFrameType.NFT_DIAMOND_ORNAMENT // Diamond pattern NftFrameType.NFT_MINIMAL_WIDE // Minimal wide border NftFrameType.NFT_MINIMAL_GREY // Minimal grey border NftFrameType.NFT_BLOCKY // Pixelated/blocky NftFrameType.NFT_GOLD_EDGES // Gold edge trim NftFrameType.NFT_GOLD_CARVED // Carved gold NftFrameType.NFT_GOLD_WIDE // Wide gold border NftFrameType.NFT_GOLD_ROUNDED // Rounded gold NftFrameType.NFT_METAL_MEDIUM // Medium metal NftFrameType.NFT_METAL_WIDE // Wide metal NftFrameType.NFT_METAL_SLIM // Slim metal NftFrameType.NFT_METAL_ROUNDED // Rounded metal NftFrameType.NFT_PINS // Pinned to wall NftFrameType.NFT_MINIMAL_BLACK // Minimal black NftFrameType.NFT_MINIMAL_WHITE // Minimal white NftFrameType.NFT_TAPE // Taped to wall NftFrameType.NFT_WOOD_SLIM // Slim wood NftFrameType.NFT_WOOD_WIDE // Wide wood NftFrameType.NFT_WOOD_TWIGS // Twig/branch wood NftFrameType.NFT_CANVAS // Canvas style NftFrameType.NFT_NONE // No frame ``` ## Check Player Wallet Use `getPlayer()` from `@dcl/sdk/src/players` to get the player's Ethereum address via `player.userId`. Always check `isGuest` before any blockchain interaction -- guest players don't have a connected wallet. ## Signed Requests Use `signedFetch` from `~system/SignedFetch` to send authenticated requests to a backend. It automatically injects signed identity headers (ADR-44) that your backend verifies — you do not build or pass them yourself. - Signature: `signedFetch({ url, init: { method?, headers?, body? } })`. - Response is `{ ok, status, statusText, headers, body }`; **`body` is a string** — call `JSON.parse(response.body)` (there is no `.json()`). - It does **not** require prior player interaction (unlike restricted actions). - Need only the signed headers for a library that does its own fetching? Use `getHeaders({ url, init? })` from the same module — it returns `{ headers }`. ## Smart Contract Interaction For direct smart contract calls, use `eth-connect` with `createEthereumProvider` from `@dcl/sdk/ethereum-provider`. Store ABIs in separate files, create a contract instance via `ContractFactory`, then call read (no gas) or write (requires gas, prompts user to sign) functions. ```bash npm install eth-connect ``` Read operations (view/pure functions) don't require gas. Write operations prompt the player to sign and require gas. Wrap all async blockchain calls in `executeTask(async () => { ... })`. Handle errors gracefully — blockchain operations can fail (rejected by user, insufficient gas, network issues). ## Gas Price and Balance Use `requestManager.eth_gasPrice()` and `requestManager.eth_getBalance()` from `eth-connect` to check current gas prices and account ETH balances. ## Custom RPC Calls Use `sendAsync` from `~system/EthereumController` for low-level Ethereum RPC calls not covered by eth-connect helpers. ## Opening External URLs / NFT Dialogs Use `openExternalUrl` and `openNftDialog` from `~system/RestrictedActions` to open external links and NFT detail views. ## Testing with Sepolia For development, use the Sepolia testnet: set MetaMask to Sepolia, get test ETH from a faucet, deploy contracts to Sepolia. Contract addresses differ between mainnet and testnet. ## dcl-crypto-toolkit (Higher-Level API) For common blockchain operations, use `dcl-crypto-toolkit` instead of raw `eth-connect`. It provides a cleaner API for the most frequent tasks. ```bash npm install dcl-crypto-toolkit ``` Import: `import * as crypto from 'dcl-crypto-toolkit'`. Modules: `ethereum`, `mana`, `currency`, `nft`, `marketplace`, `services`, `wearable`, `contract`. There is NO top-level `crypto.signMessage`. **Capabilities:** - **MANA operations:** send, check balance (`crypto.mana.send` / `.myBalance` / `.balance`) - **ERC20 tokens:** send, check balance, check/set allowance (`crypto.currency.*`) - **ERC721/NFT:** check tokens held (token gating), transfer, approval management (`crypto.nft.*`) - **Marketplace:** buy (`executeOrder`), sell (`createOrder`), cancel (`cancelOrder`), check authorization (`crypto.marketplace.*`) - **Sign message:** sign EIP-712 typed data with player wallet (`crypto.ethereum.signMessageAdvanced()`) ## Token Gating **By NFT ownership:** Use `crypto.nft.checkTokens(contractAddress, tokenIds?)` — returns whether the player holds tokens of that contract. Omit `tokenIds` to check any token of the contract. Grant or deny access on the result. **By MANA balance:** Check `crypto.mana.myBalance()` (or `crypto.currency.balance(contractAddress, address)` for other ERC20 tokens) to gate access based on holdings. ### Quick Decision Guide | Task | Use | |---|---| | Send MANA | `crypto.mana.send()` | | Check own MANA balance | `crypto.mana.myBalance()` | | Check any address's MANA balance | `crypto.mana.balance(address)` | | Send any ERC20 token | `crypto.currency.send()` | | Check ERC20 balance | `crypto.currency.balance(contract, address)` | | Transfer an NFT | `crypto.nft.transfer()` | | Check NFT ownership / token gating | `crypto.nft.checkTokens()` | | Buy from marketplace | `crypto.marketplace.executeOrder()` | | List NFT for sale | `crypto.marketplace.createOrder()` | | Sign a message | `crypto.ethereum.signMessageAdvanced()` | | Custom smart contract | `eth-connect` (see above) | | Authenticated API call | `signedFetch` (see above) | ## Example scenes Engine-team test scenes exercising these APIs against the real runtime: - https://github.com/decentraland/sdk7-test-scenes/tree/main/scenes/5,90-scene-bounds-check — `NftShape.create()` with a live `urn:decentraland:ethereum:erc721::` URN, mounted on a moving platform that carries it across the parcel boundary (so it also shows an NFT frame being culled out of bounds). - https://github.com/decentraland/sdk7-test-scenes/tree/main/scenes/80,-4-restricted-actions — `openNftDialog({ urn })` and `openExternalUrl` driven from React-ECS buttons, alongside every other RestrictedAction. Note the scene declares neither `OPEN_EXTERNAL_LINK` nor an NFT permission in `requiredPermissions` and both still run. - https://github.com/decentraland/sdk7-test-scenes/tree/main/scenes/66,6-signed-fetch — `signedFetch` on click; reads `response.ok`/`.status`/`.body` and inspects the auto-added signature headers, with an empty `requiredPermissions`. For full code examples and implementation patterns, including the dcl-crypto-toolkit library API, see '{baseDir}/references/blockchain-patterns.md'.