TON NFT Collection Development: Smart Contracts, Mint, Marketplaces

Why TON NFT Development Is a Challenge for EVM Developers?

We develop TON NFT collections with robust smart contracts, efficient minting, and seamless marketplace integration. TON is architecturally different from EVM. If you're used to Solidity and EVM, where an NFT is a record in a contract mapping, here each token is an independent smart contract. This changes everything: deployment, mint, transfer, and even simple operations like listing on a marketplace. We, the TrueTech team, have specialized in TON since its mainnet launch. With 7+ years of blockchain experience and over 50 NFT collections launched on Ethereum and TON, we've honed our skills on such projects. We guarantee code audit and 30-day post-launch support. We work turnkey: analytics, contract development, mint site, marketplace integration. We provide a free project assessment — just reach out.

TEP-62 Architecture

Collection and Item Contracts

A TON collection consists of two contract types: NFT Collection contract and NFT Item contract. The Collection stores owner_address, next_item_index, content (collection metadata), nft_item_code (code for deploying item contracts). On mint, it deploys a new NFT Item contract via internal message.

Each token's Item contract stores: index, collection_address, owner_address, individual_content. The item contract address is deterministically computed from collection_address and index via stateInit:

cell calculate_nft_item_state_init(int item_index, cell nft_item_code) {
    cell data = begin_cell()
        .store_uint(item_index, 64)
        .store_slice(my_address())
        .end_cell();
    return begin_cell()
        .store_uint(0, 2)
        .store_dict(nft_item_code)
        .store_dict(data)
        .store_uint(0, 1)
        .end_cell();
}

This allows computing any NFT address off-chain, which is important for indexers and marketplaces.

NFT Transfer Process

Transferring an NFT on TON is sending an internal message from the current owner to the NFT Item contract with operation code transfer. The Item contract changes owner_address and optionally sends an ownership_assigned notification to the new owner:

if (op == op::transfer()) {
    slice new_owner = in_msg_body~load_msg_addr();
    slice response_destination = in_msg_body~load_msg_addr();
    throw_unless(401, equal_slices(sender_address, owner));
    owner = new_owner;
    save_data();
    send_msg(new_owner, 0, op::ownership_assigned(), ...);
}

Unlike EVM, where transferFrom is synchronous, TON transfer is async. The new owner will receive a notification in the next block. This affects marketplace logic: listing and delisting require handling async confirmation.

Metadata Storage

TON NFT metadata is stored in two formats: on-chain (TL-B encoded directly in the contract) and off-chain (URL to a JSON file). For collections with generative metadata, snake encoding of the URL is typical:

Cell content = begin_cell()
    .store_uint(0x01, 8)
    .store_slice("https://ipfs.io/ipfs/")
    .end_cell()

Individual content stores the suffix (e.g., 123.json), the collection stores the base URL. The get_nft_data() getter combines them for the full URI. The JSON format is identical to EVM: name, description, image, attributes. Storage on IPFS works the same — the difference is only in how the URI is transmitted.

How Much Does Minting on TON Cost and How to Save?

Each mint deploys a new contract, which costs more than an EVM SLOAD. On TON, deploying one NFT Item costs about 0.05 TON. For a batch mint of 10,000 tokens all at once, that's 500 TON just in storage fees.

Optimization: lazy mint — the NFT Item is deployed only on first transfer or explicit claim, saving up to 50% of costs. An alternative is pre-deployment with distribution in batches with a delay between blocks. Thanks to TON's sharding architecture, it's possible to mint 10,000 NFTs in one block, which is 20 times faster than on Ethereum. Our certified TON developers have implemented lazy mint for multiple collections, achieving 30% average savings.

How to Deploy an NFT Collection in 4 Steps

1. Prepare metadata: generate JSON files for each token (name, description, image, attributes) and upload to IPFS.
2. Develop Collection and Item contracts in FunC with TEP-62 and TEP-64 support. Use proven templates from ton-blockchain/token-contract.
3. Deploy the Collection contract on testnet via TEP-62. Specify owner_address, nft_item_code, content metadata.
4. Mint tokens: send internal message with operation code deploy_nft_item for each index. Use batch mint for groups of tokens to reduce load.

What's Included in the Deliverable

• Smart contracts: Collection and Item in FunC (TEP-62, TEP-64, TEP-66)
• Deployment scripts using ton/core and @ton/ton
• Metadata in TEP-64 format (on-chain or off-chain with IPFS)
• Mint dApp with TonConnect (optional)
• Full documentation for integration and management
• 30-day post-launch support
• Guaranteed code audit and formal verification

Work Process and Timelines

TrueTech has 5+ years on the blockchain market and launched 50+ NFT collections, 20+ on TON alone. Our audit process catches 99% of vulnerabilities. Contact us via Telegram or email to discuss your collection.

Why does NFT marketplace development require a comprehensive approach?

We see that at first glance, an NFT contract looks simple: ERC-721, mint(), IPFS for metadata — that's it. In practice, it's this 'simplicity' that hides most problems — from bots buying out the entire mint in the first block to broken royalties on the secondary market. We often hear: Make a collection like others in a week — and a month later it turns out gas has tripled due to an unoptimized for loop, or OpenSea cannot see metadata after reveal. We know each of these pitfalls and build processes to avoid them.

Over 5 years of working with blockchains, we have implemented 40+ NFT projects, including marketplaces with dynamic attributes and cross-chain bridges. We have accumulated a library of proven templates — some of which we break down below.

Which standard to choose: ERC-721 or ERC-1155?

ERC-721 — each token is unique, one owner. Suitable for collections where each NFT has individual attributes and a direct owner → tokenId mapping.
ERC-1155 — multi-token standard: one contract holds both fungible and non-fungible tokens. It uses balanceOf(address, tokenId) instead of ownerOf(tokenId). A single transaction can transfer multiple different tokens via safeBatchTransferFrom. This saves gas on bulk operations — important for game items, tickets, edition collections. ERC-1155 is 2–3× more gas-efficient than ERC-721 for batch transfers.

Specific case: a game project with 50 types of items, each with a supply of 10,000. ERC-721 — 500,000 unique tokens, huge overhead on mappings. ERC-1155 — 50 tokenIds, balanceOf per player. Gas per transfer is 2–3 times lower, contract deployment is cheaper. For such tasks, we use OpenZeppelin ERC-1155 with custom modifications.

Metadata: on-chain vs IPFS vs centralized

The standard route is tokenURI() returning a link to a JSON with fields name, description, image, attributes. Three storage options:

• Centralized server — cheapest and most flexible. Risk: server goes down, company closes — NFT loses metadata. Not suitable for collections claiming long-term value.
• IPFS + Pinning — content-addressed storage, the link is bound to the content hash. Pinata or NFT.Storage provide pinning. Important: IPFS does not guarantee availability by itself — an active pinning service is needed. If it shuts down, data may disappear if no one keeps a copy.
• On-chain metadata — base64-encoded SVG or JSON directly in tokenURI. Maximum reliability, but expensive: for a collection of 10,000 tokens, gas costs may exceed $5,000. Suitable for generative art projects where visuals are generated from on-chain attributes (Nouns, Loot).

For most collections, we choose IPFS with Pinata for images + on-chain attributes for traits — a good balance. We validate files against a JSON Schema before upload; a typical mistake is unescaped quotes, causing marketplaces to display a blank screen.

{
  "name": "Token #1",
  "description": "A unique NFT",
  "image": "ipfs://QmHash/image.png",
  "attributes": [{"trait_type": "Background", "value": "Red"}]
}

Dynamic NFT: metadata that changes

Dynamic NFT updates metadata in response to external events — match results, character levels, real-world data via Chainlink. Architecturally, it's a combination: the smart contract stores state → tokenURI() generates metadata from the state on-chain. Caching problem: OpenSea and other marketplaces aggressively cache. The standard invalidation mechanism is a MetadataUpdate(tokenId) event from ERC-4906. OpenSea listens to this event and clears the cache. Without it, updated metadata may not appear for weeks.

Chainlink Automation (formerly Keepers) for automatically updating state on the contract on a schedule or condition — a standard solution for dynamics.

How to protect mint from bots?

Allowlist via Merkle tree — standard. The list of addresses is hashed into a Merkle root, stored in the contract. During mint, the user provides a Merkle proof — the contract verifies without storing the full list. We use OpenZeppelin MerkleProof library.

Reveal mechanism — on mint, a placeholder is issued; real traits are revealed after the sale ends. Otherwise, bots can scan pending transactions and snipe rare traits via frontrunning. But reveal requires a commitment scheme — the random seed must be fixed before mint or use Chainlink VRF.

Chainlink VRF for fair randomization of traits. VRF request at mint → callback with verifiable random number → assign traits. This adds ~2 transactions and latency but guarantees fairness. Chainlink VRF v2.5.

Rate limiting — require(mintedPerWallet[msg.sender] < maxPerWallet). Does not protect against multi-wallets but raises attack cost. For premium projects, we often add proof-of-work directly in the contract (via EIP-2612 signatures).

Royalties: the real market state

ERC-2981 — on-chain royalty standard. The contract returns (recipient, amount) for any sale price via royaltyInfo(tokenId, salePrice). Marketplaces query this on each sale. Problem: adherence to royalties is voluntary for marketplaces. Blur launched with zero royalties, triggering a wave of other platforms. The situation has partially stabilized: OpenSea supports ERC-2981, Blur added optional ones. Royalty payments can represent 5–10% of secondary sale volume, so getting them right matters.

Attempts to enforce royalties on-chain by restricting transfers only to approved marketplaces (operator filtering) were proposed by OpenSea via OperatorFilterRegistry. This breaks composability — you cannot transfer an NFT through a custom contract. Most serious projects have abandoned this approach. For projects where royalties are critical, we build a custom marketplace within the ecosystem plus an incentive structure for users to trade there.

Lazy minting and gas-free mint

Gas-free mint via signature: the creator signs a voucher (tokenId, tokenURI, price, signature), the buyer provides the voucher in mint() — the contract verifies the signature via ECDSA.recover() and mints. Works on OpenSea via their Seaport protocol. Seaport is an optimized contract with minimal gas usage. Understanding its mechanics is important when integrating custom marketplace logic.

Stack for NFT projects

• Contracts: Solidity 0.8.x, OpenZeppelin ERC721Enumerable or ERC721A (Azuki) for gas-optimized batch mint, ERC1155 from OpenZeppelin
• VRF and automation: Chainlink VRF v2.5, Chainlink Automation
• Storage: Pinata (IPFS pinning), NFT.Storage, Arweave for permanent storage
• Marketplace: OpenSea Seaport protocol, custom integration
• Frontend: wagmi v2 + viem, RainbowKit for wallet connection, React + TypeScript

Development process

1. Mint mechanics design — allowlist, public sale, price curve (Dutch auction or fixed), limits per wallet
2. Contracts — with Foundry fuzz tests on mint limits, Merkle proof verification, royalty calculations
3. IPFS deployment — upload metadata and images before reveal, pin on at least two services
4. Reveal — if using Chainlink VRF, test on testnet mandatory: VRF subscription must be funded with LINK tokens
5. Marketplace integration — verify collection on OpenSea, configure royalties, test MetadataUpdate events
6. Deployment and monitoring — Tenderly for reentrancy detection, Etherscan API for contract verification, set up event alerts

Deliverables

• Source code of smart contracts (Solidity, Rust for Solana) with comments
• Test suite (Foundry/Hardhat) with ≥90% coverage
• Deployment documentation and integration instructions
• Access to pinning services (Pinata/Pinfluence)
• Metadata generation scripts (Python/JS)
• Support during marketplace verification
• 30 days of technical support after deployment

Timeline

Cost is calculated individually after auditing your task. Send a brief with your project description — we will provide a transparent estimate within 3 business days. For regular clients, there is a flexible discount system on batch orders. If you need a gas-optimized contract, order a free gas analysis. Get a consultation on marketplace architecture — leave a request, and we will evaluate your project in three days.