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evm-nfts

Implement ERC-721 and ERC-1155 NFT contracts with minting, metadata, royalties, and Seaport marketplace integration.

6|20|Updated Mar 14, 2026
Search Tags:#minting#erc-721#solidity#nft#openzeppelin#seaport#erc-1155
One-click install
npx skills add https://github.com/andresdefi/cryptoskills --skill evm-nfts-andresdefi
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: evm-nfts
Source: https://github.com/andresdefi/cryptoskills/tree/main/skills/evm-nfts
Command: npx skills add https://github.com/andresdefi/cryptoskills --skill evm-nfts-andresdefi

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? NFT development on EVM chains is full of subtle traps: reentrancy through _safeMint, replayable allowlist signatures, broken OpenZeppelin v4-to-v5 migrations, misunderstood ERC-1155 URI substitution, and marketplace integrations built on deprecated protocols like Reservoir or Seaport 1.4. This Skill provides correct, current patterns for ERC-721 and ERC-1155 development using OpenZeppelin v5.6.1 and Seaport 1.6. ## Core Features & Use Cases - Secure Minting Patterns: Ready-to-use Solidity contracts for Merkle allowlists, EIP-712 signed allowlists with nonces and deadlines, Dutch auctions, commit-reveal, and free claims, all guarded with ReentrancyGuard. - Metadata & Royalties: Complete JSON metadata schemas, ERC-4906 update events, ERC-2981 royalty implementation, and ERC-721C enforced-royalty patterns via transfer validators. - Marketplace Integration: Seaport 1.6 listing and fulfillment examples in TypeScript with viem and the Seaport SDK, plus verified contract addresses across all EVM chains. - Use Case: You need to launch a 10,000-item ERC-721 collection with an allowlist phase, per-wallet limits, 5% royalties, and OpenSea compatibility. Use the provided AllowlistCollection contract, Merkle tree generation script, and Foundry tests to deploy with confidence. ## Quick Start Ask the AI to generate an ERC-721 collection contract with a Merkle allowlist mint, supply cap, and ERC-2981 royalties using OpenZeppelin v5.6.1.

Frequently Asked Questions about evm-nfts

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I create an ERC-721 allowlist mint in Solidity?▼

Use a Merkle proof or EIP-712 signature allowlist with OpenZeppelin v5.6.1. Verify the proof against a stored merkleRoot, track claimed addresses in a mapping, and apply ReentrancyGuard because _safeMint makes an external call to the receiver.

What changed in OpenZeppelin v5 for ERC-721 contracts?▼

OpenZeppelin v5 removed Counters, replaced _beforeTokenTransfer with the _update hook, and requires an initialOwner argument in the Ownable constructor. Use uint256 _nextTokenId directly and check _ownerOf(tokenId) != address(0) instead of _exists.

How does ERC-1155 URI id substitution work?▼

The uri() function returns a template containing {id}, which clients replace with the token ID in hex, zero-padded to 64 characters, lowercase, without a 0x prefix. Token ID 1 becomes 0000...0001. The substitution is client-side per the ERC-1155 spec.

Are ERC-2981 royalties enforced onchain?▼

No, ERC-2981 is a read-only interface that marketplaces can ignore. For onchain enforcement, use ERC-721C with a transfer validator that whitelists royalty-paying marketplaces and blocks non-compliant operator transfers.

Why does my NFT metadata not show on OpenSea?▼

Common causes are tokenURI returning an image URL instead of JSON, missing contractURI for collection metadata, or stale caches. Emit ERC-4906 MetadataUpdate events and call the OpenSea metadata refresh API endpoint to trigger re-indexing.

What Seaport version should I use for NFT marketplace integration?▼

Use Seaport 1.6 at 0x0000000000000068F116A894984e2DB1123eB395, deployed at the same address on all EVM chains. Seaport 1.4 and 1.5 have known issues, and Reservoir shut down in October 2025.

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