Skill Guide

NFT smart contract basics - ERC-721, ERC-1155, Metaplex on Solana

NFT smart contract basics involves understanding the programmable logic (primarily Solidity and Rust) that defines non-fungible token standards-ERC-721 for unique 1:1 assets, ERC-1155 for multi-token/mixed fungibility batches, and Metaplex on Solana for high-throughput, low-cost NFT minting and management.

This skill is critical because it enables the creation of verifiable digital ownership and programmable royalties, directly impacting new revenue streams for IP holders and loyalty engagement for brands. Mastery allows organizations to build proprietary digital asset ecosystems rather than relying on third-party marketplaces.

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How to Learn NFT smart contract basics - ERC-721, ERC-1155, Metaplex on Solana

Focus on Solidity fundamentals (variables, functions, state) and the official ERC-721/1155 interface specifications (EIPs). Use OpenZeppelin's wizard to deploy your first ERC-721 contract to a testnet like Sepolia.

Integrate IPFS/Arweave for decentralized metadata storage and learn to batch mint with ERC-1155 to optimize gas. Study common pitfalls like reentrancy and incorrect royalty calculations (EIP-2981).

Architect cross-chain compatibility strategies and design gas-optimized storage layouts. Evaluate trade-offs between Ethereum L1, L2s (like Polygon), and alternative L1s (Solana) for specific use cases (e.g., gaming vs. art).

Practice Projects

Beginner

Project

Deploy a Basic ERC-721 NFT Collection

Scenario

You are tasked with creating a 100-item generative art collection where each NFT has unique metadata and a 5% royalty on secondary sales.

How to Execute

1. Set up a Hardhat/Foundry environment. 2. Inherit OpenZeppelin's ERC721 and ERC721Royalty contracts. 3. Write a `mint` function that assigns a token ID and a token URI. 4. Deploy to Sepolia and verify on Etherscan.

Intermediate

Project

Build an ERC-1155 Gaming Item Contract

Scenario

A game needs a contract to manage 50 different in-game item types (swords, potions), some fungible (potions), some unique (legendary swords), with a unified sale event.

How to Execute

1. Define token IDs (e.g., 1-40 for common items, 41-50 for uniques). 2. Implement `mintBatch` for efficient supply management. 3. Integrate a sale contract that accepts ETH and calls `safeTransferFrom`. 4. Test minting, burning, and transfer logic.

Advanced

Project

Metaplex Candy Machine V2 Launch

Scenario

Launch a 10,000 PFP collection on Solana with a fair mint, whitelist phase, and reveal mechanism, ensuring bot resistance and low transaction fees.

How to Execute

1. Prepare assets using Metaplex CLI (upload to Arweave). 2. Configure `config.json` with phases, prices, and go-live dates. 3. Deploy using `sugar deploy`. 4. Integrate a front-end using `@metaplex-foundation/js` for minting. 5. Monitor and manage with `sugar guard` for bot mitigation.

Tools & Frameworks

Smart Contract Development & Deployment

OpenZeppelin ContractsHardhatFoundryRemix IDEAnchor Framework (Solana)

Use OpenZeppelin for audited, reusable contract modules. Hardhat/Foundry for testing, scripting, and deploying Ethereum contracts. Anchor is the standard for building and testing Solana programs.

NFT-Specific Platforms & Storage

Metaplex (Candy Machine, Auction House)Alchemy/Infura (Node Providers)IPFS/PinataArweave

Metaplex is the end-to-end standard for Solana NFTs. Use Alchemy/Infura for reliable Ethereum RPC endpoints. IPFS and Arweave provide decentralized, permanent storage for token metadata and assets.

Testing & Analysis

Slither (Static Analysis)Tenderly (Transaction Simulation)Etherscan/Solscan (Explorers)Mocha/Chai (Testing)

Slither identifies security vulnerabilities. Tenderly allows debugging of failed transactions. Block explorers are essential for verifying contract state and ownership. Mocha/Chai is the standard for JavaScript-based tests in Hardhat.

Interview Questions

Answer Strategy

The interviewer is testing conceptual clarity and applied business logic. Define each standard technically, then map to use cases. Answer: ERC-721 uses a unique mapping from tokenId to owner, ideal for 1:1 assets like art or deeds. ERC-1155 uses a single contract for multiple token types with balances per address, optimizing gas for batch operations like game items. I'd recommend ERC-1155 for a gaming platform with hundreds of item types to reduce deployment costs, but ERC-721 for a high-value, unique art collection where provenance is paramount.

Answer Strategy

Tests knowledge of recent standards and defensive coding. Answer: I check for EIP-2981, the NFT Royalty Standard. Key pitfalls: 1) Not supporting the `royaltyInfo` view function correctly for marketplace queries. 2) Incorrectly calculating the royalty amount (e.g., using integer math vs. basis points). 3) Not allowing the receiver address to be set to zero for opt-out.