# Cross-chain NFTs ⛓️ *Author: William M. Peaster* *Published: Oct 31, 2023* *Source: https://www.bankless.com/de/cross-chain-nfts* --- Dear Bankless Nation, New L1s and new L2s continue to proliferate. That said, the Ethereum Virtual Machine (EVM) compatibility paradigm and UX strides will make moving fungible tokens across chains increasingly streamlined. But what about for non-fungible tokens, what options exist for NFTs to move from one chain to another? Let’s answer that question by going over the basics of cross-chain NFT approaches for today’s post! -WMP --- # **An Intro to Cross-Chain NFTs** --- > There’s no one “right way” per se when it comes to moving an NFT from one chain to another, as we’ve seen a range of different approaches used for this to date, all with their own tradeoffs. For me, the first approach that comes to mind here is what I’d call **equivalent bridging**, like as in moving an NFT from Ethereum to a different chain that’s *effectively equivalent* to Ethereum at the protocol level, e.g. the [Optimism](https://help.optimism.io/hc/en-us/articles/8004922894491-What-is-the-difference-between-EVM-equivalence-and-Ethereum-equivalence) layer-two (L2) scaling solution. Indeed, after its Bedrock upgrade earlier this year Optimism boasts near-perfect Ethereum equivalence, so if you bridge an NFT from Ethereum to Optimism it’s sort of like bridging an NFT *from Ethereum to Ethereum*. The Quix marketplace (which became community-run earlier this year) has offered such [an NFT bridge](https://qx.app/bridge) previously, but now it might just be a theoretical example — I wasn’t able to get it to work when I last tried. You get the idea though!Admittedly, we haven’t seen much equivalent bridging in the NFT ecosystem yet. What has been much more common, though, is collection-wide migrations using the cruder but also fairly practical **burn-and-mint** method. By burn-and-mint, I mean a process in which a collection holder can burn their NFT on one chain and then receive an official collection-approved re-mint of it on a new chain. This is typically just cast as a “bridging” experience. An example here would be y00ts, which has used this method not once but twice in migrating [from Solana to Polygon](https://decrypt.co/124887/at-least-37m-worth-of-y00ts-nfts-migrate-to-polygon-from-solana-in-one-day) and then [from Polygon to Ethereum](https://twitter.com/y00tsNFT/status/1713716513994359130). ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2fdb661ff9-fba4-42c6-bd9d-874d1b00f2a5_1600x1600-jpeg.jpg) > Another approach that’s growing in popularity lately is the **lock-and-mint** method popularized by the [omnichain NFTs](https://layerzero.gitbook.io/docs/evm-guides/layerzero-omnichain-contracts) of interoperability protocol LayerZero. You might have seen this in action before via the [Lil Pudgys Bridge](https://bridge.pudgypenguins.com/), which supports transfers to [Arbitrum, BNB Chain, and Polygon](https://twitter.com/pudgypenguins/status/1618288231552004100). ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2fceebfef3-f0ab-4ca9-adf3-a7f635001d61_1600x775-png.jpg) > The way this architecture works is that LayerZero offers a smart contract system that lets you turn a regular NFT into an **ONFT**, after which you can deploy that ONFT on LayerZero-supported chains. To then move cross-chain, the ONFT becomes locked on the source chain and minted on the destination chain, and to move back, the ONFT becomes locked on the new source chain and the *original* NFT becomes unlocked on the *original* source chain. ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2f5e41d3e2-dcff-4a68-bf5f-92d363dd0afd_1427x548-png.jpg) > Yet LayerZero is just *one* interoperability protocol. A project notably building support for LayerZero and additional messaging protocols simultaneously is [Holograph](https://www.holograph.xyz/). ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2fbbff5a88-94c8-4af4-83fe-dc97341b3b8a_1200x1200-jpeg.jpg) > Zooming in, Holograph has created a new primitive known as [Holographic Assets](https://twitter.com/holographxyz/status/1679521221539667968), an instance of which are **hNFTs** that let you mint NFTs that “maintain the same contract address and token ID on all EVM environments, enabling them to move between blockchains with perfect provenance.”For anyone who remembers my recent [RWA x NFTs post](https://bankless.ghost.io/rwas-nfts/), note that Holograph is working toward hNFTs as a [standard for tokenizing real world assets](https://twitter.com/holographxyz/status/1703801072366841877) and “decoupling the asset layer from the blockchain layer.”On the point of additional messaging protocols, though, another one that shows great promise is Chainlink’s new **Cross-Chain Interoperability Protocol** (CCIP). Of course, the [CCIP system](https://www.bankless.com/early-access-sergey-nazarov-on-chainlinks-ccip) is aimed at doing much more than *just* supporting cross-chain NFTs, but here it can excel across a range of use cases like [cross-chain games, cross-chain NFTfi, and universal NFTs](https://blog.chain.link/cross-chain-nft/). Affine, a DeFi project, is specifically tapping this system to power its [Affine Pass NFTs](https://blog.affinedefi.com/affine-integrates-chainlink-ccip-to-help-unlock-cross-chain-nft-bridging-8065427cbc9e), for example. ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2f310ad9ce-75d9-4185-b6ea-59f23337170c_1600x667-png.jpg) > So while some efforts like CCIP want to offer a way for *everything* to be made cross-chain compatible, on the flip side some projects are building their own bespoke cross-chain solutions for their own singular needs. Toward this end, the onchain RPG Pirate Nation comes to mind, as it’s developed a custom **Mirroring system** that facilitates a [Trade on L1 / Play on L2](https://twitter.com/PirateNationNFT/status/1641530804617756672) method: the original Founder’s Pirates NFTs stay on Ethereum while their mirrors on Arbitrum Nova facilitate gas-free gameplay. ![](https://storage.ghost.io/c/e4/b7/e4b77544-5a37-4f0b-8824-8440aa348476/content/images/2024/02/https-3a-2f-2fsubstack-post-media-s3-amazonaws-com-2fpublic-2fimages-2ff2918b24-731f-49ea-9841-1e3b9000170e_1343x750-png.jpg) > This concept brings us full circle to having NFTs on one chain but not having to move them cross-chain at all in order to “use” them on another chain. This type of utility is made possible by services like [UMA’s Optimistic Oracle](https://docs.uma.xyz/developers/optimistic-oracle-v3), which can consider NFTs on one chain while enforcing actions on another.To close and zoom back out, then, it’s clear that where NFTs are concerned the lines between blockchains are increasingly blurring as cross-chain efforts of all stripes are starting to gain ground. In the near term, there will be various challenges and obstacles to face in this arena, but there will also be new possibilities, new innovations, and new experiences. Keep your eyes peeled here accordingly!