Showcase 01 — EvmWal NFT

02 · the shape

One mint, two write paths, one read path.

The contract is an OpenZeppelin ERC721 + ERC721URIStorage. mint(string) assigns a token id and stores the string verbatim. There is no Walrus-specific code on chain.

The browser uploads bytes to either a local Next.js API route that signs Sui transactions with an operator keypair (default), or directly to the public Walrus testnet publisher (set NEXT_PUBLIC_WALRUS_UPLOAD_MODE=publisher). Both paths return the same 32-byte blobId and lead to the same aggregator URL.

The migration cost from IPFS is changing one URL prefix. The Solidity side does not move.

// the entire EVM-side contract surface
function mint(string tokenURI_)
  external returns (uint256);
function mintTo(address to, string tokenURI_)
  external returns (uint256);
event Minted(
  uint256 indexed tokenId,
  address indexed minter,
  string tokenURI_
);

file picker

→

walrus write

→

mint(uri)

03 · try it locally

Five terminal commands and a wallet popup.

Prerequisites

Node 22, pnpm 10, Foundry, and an injected EVM wallet (MetaMask / Rabby / Coinbase Wallet extension). No real ETH needed — the deploy script funds itself from Anvil dev-0.

nvm use (or install node@22 any other way)
corepack enable && corepack prepare pnpm@10.32.1 --activate
curl -L https://foundry.paradigm.xyz | bash && foundryup

Backend (default) upload mode also needs a Sui testnet keypair plus testnet SUI and testnet WAL. Publisher mode skips all Sui-side setup.

Clone and install

git clone git@github.com:MystenLabs/evm-sui.git
cd evm-sui
pnpm install
cp showcases/01-evmwal-nft/web/.env.local.example showcases/01-evmwal-nft/web/.env.local

Edit web/.env.local: paste SUI_PRIVATE_KEY=suiprivkey… for backend mode, or set NEXT_PUBLIC_WALRUS_UPLOAD_MODE=publisher to skip the Sui side entirely.

Start a local chain

# terminal A — repo root
pnpm dev:chain    # anvil on 127.0.0.1:8545

Anvil pre-funds 10 deterministic wallets; the first one is what deploy:local uses below.

Deploy + sync the ABI into the web app

# terminal B — inside showcase 01
cd showcases/01-evmwal-nft
pnpm deploy:local
# → forge script DeployEvmWalNFT.s.sol  → broadcast
# → write-deployed-address.ts            → .deployed-address
# → extract-abi.ts                       → web/lib/contract.ts + web/.env.local

The script reads the Foundry broadcast artifact, captures the deployed address, and patches it into the web app's env + ABI. Re-run any time you redeploy.

Start the dev server, connect MetaMask, mint

pnpm dev:web        # http://localhost:3000

In MetaMask: add the Anvil network (chain id 31337, RPC http://127.0.0.1:8545), switch to it, then open http://localhost:3000. Hit the Mint tab, pick an image, watch the upload + mint flow. The card appears in All NFTs and My NFTs within seconds of confirmation.

04 · verify

What "good" looks like.

The post-mint success panel shows the tokenId, blobId, and (in backend mode) the on-Sui Blob object id.
Clicking any NFT card opens its blob on Walruscan — the canonical content-addressed view.
In backend mode, the Suiscan link on the success panel shows the Blob Move object you (the operator) own — you can extend its end_epoch or transfer it on chain.
Switch to publisher mode and repeat: same tokens, same aggregator URLs, but no Sui-side wallet involved.

05 · what this is NOT

Limits to set expectations.

Not production-deployable as-is. The backend upload route at /api/walrus/upload is unauthenticated. It spends operator WAL on every successful request. Run on a local dev server only.
Not a Walrus pricing oracle. epochs: 5 (~14 days) is the default; operator picks the retention window and pays upfront.
Not infinite scale. The gallery scans 1..totalSupply on every render — snappy below ~100 tokens; for real scale you'd want a subgraph or a Transfer event indexer.
Not a hash verifier. Trust in the bytes served by the aggregator is identical to trust in an IPFS gateway. For trustless retrieval, add a Reed-Solomon recompute via @mysten/walrus on top.

Mint an NFT whose image lives on Walrus, not IPFS.

NFT.Storage's quiet collapse left every drop on borrowed time.

One mint, two write paths, one read path.

Five terminal commands and a wallet popup.

Prerequisites

Clone and install

Start a local chain

Deploy + sync the ABI into the web app

Start the dev server, connect MetaMask, mint

What "good" looks like.

Limits to set expectations.

Where to look in the repo.