Sandbox is a LAND purchase signing, ownership, and network workflow

Polygon now frames the purchase screen

The Polygon purchase route is the current transaction path for official LAND sales and marketplace activity inside The Sandbox. Official sales moved from Ethereum to Polygon in November 2022, so the confirmation screen should identify Polygon rather than Ethereum. POL is the network gas token, while SAND remains the payment token for platform purchases.

Polygon Mainnet uses chain ID 137, while Ethereum Mainnet uses chain ID 1. MetaMask, WalletConnect, and other EVM-compatible wallet connections expose the same address format on both networks, which makes the chain indicator essential. An identical-looking address does not mean its Ethereum SAND balance exists on Polygon.

A browser network switch changes the chain the wallet addresses; it does not bridge Ethereum SAND into Polygon SAND.

Prerequisites before the sale opens

The purchase prerequisite set is a verified account, one linked wallet, Polygon SAND, and a workable gas method. A public sale requires completed Know Your Customer verification, an eligible account, and a location permitted by the sale terms. Verification takes up to 48 hours, which makes last-minute setup unreliable.

The linked address must also hold the Polygon SAND and receive the LAND. The Sandbox permits only one wallet connected to an account at a time, and a wallet previously used with another Sandbox account cannot attach to a different one. That rule makes address selection a prerequisite, not a cosmetic setting. MetaMask and WalletConnect may expose several addresses, especially when a Ledger or Trezor is present. Compare the complete account address with the sender shown in the wallet prompt. A match keeps the interface, payment balance, and eventual ERC-721 owner record aligned.

Price and gas before confirmation

The confirmation cost panel is a split view of the LAND price, payment token, and Polygon execution charge. The sale or listing sets the SAND amount. Its fiat equivalent moves with the SAND market, while the gas estimate responds to Polygon demand at the signing moment.

The payment path has two fixed operational facts. The Sandbox assigns 10 gasless Polygon transactions to each account every 28 days. Each use covers one eligible transaction, and the account interface shows the remaining count and renewal date. After the allowance reaches zero, the wallet needs enough POL for network gas. The former setting for paying gas in SAND ended on January 23, 2025, so it should not appear as an active choice. An ERC-20 allowance request, when shown, is a separate action and may consume another gasless slot or POL fee. That distinction changes the number of confirmations.

The complete purchase requirement is therefore the quoted Polygon SAND plus either one available gasless transaction or sufficient POL. Bridging and exchange charges belong to earlier funding steps, not the LAND transfer displayed by the purchase contract.

Standard, Premium, and parcel assignment

The parcel choice screen is a sale-specific decision between an exact location and a type assigned from available inventory. A direct sale presents Standard or Premium LAND and assigns an available parcel within the featured neighborhood. An auction lets the bidder select the exact LAND or Estate coordinates before bidding.

LAND details give the allocation real dimensions. The metaverse map contains 166,464 LAND tokens arranged on a 408 by 408 grid. A 1 by 1 parcel provides a 96 by 96 block base and a 128-block height; one block represents one metre, and each block contains 32 by 32 by 32 voxels. Those figures describe the parcel footprint, not its market value. Standard and Premium LAND remain ERC-721 tokens of the same basic type. Premium marks placement near selected partner areas and may include sale-specific extras, so the preview should name both the classification and allocation method.

Five checks before signing

The pre-signing checklist is a five-point stop gate for confirming the wallet, network, asset, amount, and fee route. Each item answers a decision the interface cannot correct after the wallet broadcasts the transaction.

• Account: Completed verification and an address matching the wallet selected for payment.
• Network: Polygon Mainnet with chain ID 137 visible in the wallet prompt.
• Payment: Polygon SAND covering the complete quote shown for the selected LAND.
• Allocation: A random direct-sale parcel or the exact auction coordinates the buyer intended.
• Execution: An available gasless use or enough POL for the displayed network charge.

The contract interaction and total must match the active purchase preview, including any separate ERC-20 approval. Closing the prompt leaves the buyer free to inspect a changed quote or allocation before creating a fresh transaction.

What exactly does the wallet confirmation authorize?

The wallet confirmation is the final authorization layer between the interface preview and a broadcast Polygon transaction. It binds the selected account to the network, target contract, encoded function, SAND amount, and gas terms shown by the wallet.

A plain message signature has zero gas and normally proves control of an address for a session. It cannot, by itself, move SAND or change LAND ownership. The purchase requires an on-chain transaction confirmation. When an ERC-20 allowance is necessary, the first confirmation authorizes a contract to use a defined SAND amount, while the later confirmation executes the purchase. MetaMask presents these as separate actions because they create separate blockchain records.

Rejecting the prompt broadcasts nothing. The sale page then retains only the temporary availability rules applying to that parcel.

The on-chain state change

The executed purchase is an atomic contract state change linking SAND settlement with a specific ERC-721 LAND token. A successful transaction reduces the buyer's Polygon SAND balance, settles the quoted payment through the sale contract, emits the LAND transfer record, and assigns the token to the receiving address, which is examined in Sandbox app.

The sale inventory already contains pre-minted LAND, so purchasing and minting are distinct steps. ERC-721 identifies one NFT through the pair of its contract address and a uint256 token ID. The 256-bit token ID stays associated with that contract, while the standard ownerOf function returns the address holding it. If a contract condition prevents execution, the token movements revert together, although Polygon may still charge gas for the attempted work. A completed transfer makes the buyer's address the authoritative owner before every website index finishes updating.

Ownership checks across wallet, map, and explorer

The ownership check is a three-part comparison across the connected address, LAND contract, and token ID. PolygonScan supplies the direct transaction and contract record, while The Sandbox wallet and map present an indexed application view of the same asset.

An EVM address contains 20 bytes and normally appears as 0x plus 40 hexadecimal characters. Polygon LAND uses contract 0x9d305a42A3975Ee4c1C57555BeD5919889DCE63F. The Ethereum LAND contract introduced in January 2022 is 0x5CC5B05a8A13E3fBDB0BB9FcCd98D38e50F90c38, so Etherscan is the relevant explorer for that chain. Match all 42 displayed characters rather than relying on the collection name alone. Next, open the token ID and confirm ownerOf matches the complete wallet address linked to the account. Together, chain, contract, and token ID identify one LAND record.

Importing the Polygon contract into MetaMask only changes wallet display settings. It neither creates ownership nor moves an existing Ethereum LAND onto Polygon.

A confirmed transfer with a delayed inventory view

The delayed inventory view is an indexing issue when Polygon already records a successful LAND transfer to the buyer. Start with the transaction hash, confirm its successful status in PolygonScan, inspect the ERC-721 transfer event, and compare its recipient with the linked wallet.

The Sandbox map and wallet inventory may take a few minutes to ingest the confirmed record during busy sales. Refresh the account only after the explorer shows success, then confirm the same address remains connected. OpenSea and Rarible maintain their own indexes, so their display timing may also differ from the chain. Avoid signing a replacement purchase merely because one interface remains stale: direct sales process additional LAND one transaction at a time, and a second successful confirmation acquires another parcel. The token's contract-level owner record settles the question while application views catch up.

The wrong-network recovery path

The wrong-network message is a wallet configuration mismatch between Polygon chain ID 137 and the network requested by the purchase. It appears when MetaMask, WalletConnect, or another active wallet session remains on Ethereum, a test network, or a different EVM chain.

Switching networks changes the active ledger view, but it does not transfer SAND between Ethereum and Polygon.

Select Polygon Mainnet in the wallet, confirm chain ID 137 and the POL gas symbol, and reconnect the purchase page to the same address. If Polygon is absent, add it through the wallet's network settings before reopening the sale. Lock other browser wallets when multiple extensions compete for the same connection. A zero Polygon SAND balance after switching means the funds remain on another chain; The Sandbox Bridge handles that move through a separate transaction. The corrected session should then display the Polygon balance, quote, and confirmation request together.

Resetting balances before another purchase

The post-purchase reset is a balance and session review before the buyer attempts another one-at-a-time LAND transaction. Record the transaction hash and token ID, confirm the ERC-721 owner, and let the application inventory update. Recheck the remaining Polygon SAND because the first purchase changed it, and expect the gasless counter to fall by one when the relay covered execution. An ERC-20 allowance confirmed earlier remains a separate contract state until it is changed, so a later purchase may open directly at transaction confirmation. Direct-sale availability and assignments can change between attempts; reopening the active listing produces a fresh parcel decision, quote, and gas estimate for the next signature.