AxelART is like Instagram for AI art: instead of uploading photos, users enter text prompts used by AI to generate the images. Features include both "web 2.0" style social features like commenting, liking, and reposting, as well as (optional) web3 features like minting images as NFTs on multiple chains, powered by Axelar.

AxelART uses "account abstraction" to make it seamless for users, without needing wallets nor gas tokens to get started. Even when minting NFTs, users never have to "send transactions", "sign messages", nor write down 12- or 24-word phrases on pieces of paper.

• Try it now: https://axelart.xyz (minting on Goerli, Optimism-Goerli, Arbitrum-Goerli)
• Slide Presentation
• Demo Video: https://youtu.be/sjy7F5azLRQ

For more details on AxelART web2 and web3 features, see below

AxelART enables users to mint their own AI-generated art, or artwork created by other users. Users can mint NFTs on the chain of their choice, powered by Axelar. And thanks to Account Abstraction features powered by Gelato, user do not need a pre-existing wallet and do not need to onramp funds for gas on the desired chain/network. The goal is interchain NFTs as easy as web2.

Users can choose a preferred chain in their settings, which will be used when posting new AI-generated art. The live demo supports testnets for Ethereum, Optimism, and Arbitrum, buyt many more are planned for a production launch. When minting artwork posted by others, a dropdown is displayed for single-click interchain minting:

• To mint your own AI-generated art: check a box when creating your art.
• To mint others' art: click on the desired chain from the dropdown.

It's that easy. No messages to sign, no transactions to approve, no gas required.

As described above there are very few steps for the user, it is very easy to mint an AxelART NFT on any supported chain. The complexity has been abstracted away, with all the magic happening behind the scenes.

Most of the AxelART transactions are sent via Gelato Relay, an account abstraction service. For more about how AxelART uses Gelato Relay, see below.

The other key part of the magic is General Messaging Passing (GMP) powered by Axelar, which is used to transport NFTs from one chain to another.

AxelART's approach to interchain NFTs to seperate the NFT logic and the (interchain) transport logic into different contracts. The Transporter contract is departure and arrival hub for multiple NFT contracts/collections. The Transporter deployed for AxelART is powered by Axelar, but other transporters could use other GMP solutions.

On each chain AxelART has a single "shared" NFT contract that is the default for all FREE users. Users who pay to upgrade to PRO get their own dedicated NFT contract. On each chain their is a single Transporter contract that handles interchain transportation for all of the NFT contracts. This hub-and-spoke model help simplify things and help minmize total bytecode and thus deployment costs.

All NFTs get sent from Transporter-to-Transporter, with the departure and arrival Transporters calling the NFT contracts on each end, according to the IERC721Transportable interface. For the demo, the Transporter contracts have been deployed to 0xa64904acF704926e8032900627a5486Ee191aFe3 on Goerli, Optimism Goerli, and Arbitrum Goerli.

Calling the send() function on the Transporter contract starts the process of transporting an NFT from one chain to another. The IAxelarExecutable implemented execute() function handles to arrival of NFTs from other remote chains. send() transactions are sent via Gelato Relay using ERC2771Context with Open Zeppelin's AccessControl for secure permission. More on the latter below.

For an NFT contract to be compatible with a Transporter, it must implement the IERC721Transportable interface:

interface IERC721Transportable {
    function depart(uint256 tokenId) external;
    function arrive(address to, uint256 tokenId) external;
}

• the Transporter will call the depart() function prior to sending the NFT to another chain. Some NFT contracts will choose to burn the token prior to departure, others may transfer the token to a holding address. Some may emit an event.
• upon arrival at the destination chain, the receiving transported will call the arrive() function on contract on the destination chain. Implementing the arrive() function would be priarliy to mint the token on the destination chain.
• access control permissions to these is important, and could be implemented in various ways to suit the needs of the deployers

The goal here is for the Transporter contract to handle all the interchain GMP messaging aspects while the ERC721 NFT contracts handle only the burning/minting/transferring actions needed on each end of the transport.

As described above, from a user perspective, they simply choose a chain to receive the NFT. Behind the scenes, AxelART has a "home chain" which acts the default chain. (For the live demo, this is Goerli). When a "remote" (non-home) chain is chosen, the NFT is first minted on the home chain, then transported to the remote chain. Both of these happen behind the scenes -- the user does not have to sign any messages nor approve any messages nor pay any gas. (Side note: in production, it is likely that some "premium" or high-gas chains might only be available to paying PRO users).

Note that in additon to minting and transporting transactions, the "first mint" of the user also triggers the deployment of a Safe smart contract wallet, relevant approve() transactions, and starting a stream of pAInt tokens to the user. See below for more information on pAint tokens and the first mint. Since AxelART can be used to create AI art without minting any NFTs, on-chain transactions are only trigger once a user first chooses to mint.

Paying PRO users get their own dedicated NFT contracts, which are deployed to the home chain from the AIrtNFTFactory contract on the home chain (via Gelato Relay). When another user first chooses a remote chain for a PRO user, this triggers -- completely behind the scenes -- a deployment of the PRO user's contract on the chosen chain -- at the same address as on the home chain, plus giving the remote Transporter permissions to transport for the newly deployed contract. Once these have happened behind the scenes, the same mint + transport flow is triggered to send the NFT to the PRO contract on the remote chain. Again, the complexity is hidden from the user, who just made a single-click to mint on the chosen chain.

AxelART Transporter contracts support transportation of NFTs between any two deployed chain at any time. For example, if a user decides in future to move their NFT from Optimism to Ethereum Mainnet. This feature has not yet been exposed in the user interface for the live demo.

Using web3Auth, AxelART login options include social, email, or wallet. Social/email logins will generate an app-specific private key … behind the scenes, no seed phrase needed – only the user has access to the complete private key (self-custody), enabled by Multi-Party Computation (MPC).

Social login users:

• do not need a wallet
• do not see an EVM address
• are not asked to “sign” any messages
• do not need ETH or any other token for “gas”

Note that when choosing the wallet login option, AxelART checks for an ENS name for the connecting address, and if found, will use that as the "name" of the user on AxelART. For example, if I choose to login via web3auth using my primary Metamask address, AxelART will show me as markcarey.eth.

Several "web 2.0" style features include:

• Creating and sharing AI images. User enter text prompts to share AI-generated art. (powered by DALL-E from OpenAI)
• Liking. Users can "like" images shared by others
• Commenting. User can post comments in reply to shared images
• Reposting. This is a bit like retweeting, but with a twist. A repost does not re-share the same identical image, but rather uses the same identical text prompt to generate an entirely new image.
• Following. Users can follow other users, if they like their artwork.

Some users may optionally decide to mint images as NFTs on the blockchain, as descibed in detail above). When users post new artwork, they can:

1. Choose to immediately mint the image on the blockchain.
2. Enable others to mint the image for a price.
3. Neither (image will not be minted)

Creators can always decide later -- after posting -- to mint their own images.

Minting during art creation is done by toggling a checkbox. For images already posted, minting involves a single click/tap. In both cases, the user does not have to send transactions nor sign messages.

When minting your own artwork, it costs 1 pAInt token. When minting images posted by others, you pay the price set by the creator, denominated in either pAInt or WETH.

pAInt is a native Super Token that supports real-time streaming, powered by Superfluid. It acts as a utility token on the AxelART platform for minting NFTs. Users start with 5 pAInt and after their first mint, active users receive 3 pAInt per month, streamed in real-time.

See the streams on Superfluid Console. It's like watching paint stream.😐

When the user decides to mint their first NFT -- and not before -- on-chain transactions are triggered, behind the scenes:

1. A Safe smart wallet is deployed. This is a “1 of 3” multi-signature Safe. The user’s web3auth-generated address has full access as 1 of the 3 owners. The second owner is a AxelART Hot wallet enabling behind-the-scenes Safe transactions on the behalf of the user. The third owner is a AxelART cold wallet for emergency/recovery purposes.
2. ERC20 Approval transactions are sent from the Safe to facilitate the first and future mints.
3. Sent via Gelato Relay, a transaction is sent to start streaming 3 pAInt per month to the Safe.
4. Also via Gelato Relay, the minting transaction is sent to mint the NFT to the shared AxelART NFT contract.
5. If a remote chain is chosen, a tranport transaction is also sent via Gelato Relay.

Remember, the above 4-5 transactions happen behind the scenes. From the user's perspective all they did was check a box or tap a link.

AxelART uses Gelato Relay to send tokens and NFTs to users' Safes (and one more action discussed below). These requests are signed and submitted on-chain by Gelato relayers, with gas paid from AxelART's Gelato 1 Balance account. Each of the contracts deployed by AxelART support ERC2771 Context which enables secure transactions to be signed by AxelART but relayed onchain by Gelato Relayers. This works seamlessly with OpenZeppelin's AccessControl permissions to restrict functions to authorized signers.

Subsequent NFT minting triggers a single transaction -- via Gelato Relay -- to mint the NFT to their Safe, while withdrawing 1 pAInt from the Safe for each NFT minted of their own art (or the required amount of pAInt or WETH if minting others’ art). If a user has less than 1 pAInt they cannot mint and must wait until they accumulate enough via the incoming stream (or by other means 🦄). Again, a second transport transaction is triggered if a remote chain was chosen.

Scenario: a creator has joined AxelART and posted several images, but has not minted any yet. But the creator has enabled minting of the posts, and set prices and currencies (pAInt or WETH) in each case. What happens when another user decides to mint these images? How does the creator get paid, when no Safe has (yet) be deployed for the creator? As mentioned above, the Safe is only deployed when the user does their first mint, and not before. Even though the Safe has not been deployed, the creator still gets paid! When the creator joined AxelART, the Safe SDK is used to accurately predict the user's Safe address, even though it has not yet been deployed. This predicted Safe address is assigned to creator's user account, and when pAInt or WETH gets sent to that address, it just works, and the funds are owned by the predicted Safe address. When/if the creator triggers their first mint, the Safe will then be deployed to the predicted address and the creator will have full access to the tokens sent previously.

Since we are sponsoring -- paying the gas for -- users' transactions, using pAInt as a utility token helps limit the gas costs associated with users on the FREE plan. These users receive 3 pAInt monthly, streamed in real-time.

For serious AxelARTists, minting 3 NFTs per month may not be enough.

AxelART uses a freemium business model, where cloud-computing and gas costs are subsidized (sponsored) for FREE users, while revenue from PRO users more than offsets those costs.

AxelART PRO is a monthly subscription powered by Stripe Billing. Consistent with the goal of account abstraction, PRO users pay via credit card recurring billing (with future plans to add support for crypto-native billing options).

• a dedicated NFT contract for each PRO user (deployed from the AxelART Factory contract via Gelato Relay
• cross-chain NFT collections (PRO contract is deployed on each chain -- behind then scenes -- if/when someone want to mint on those chains)
• increased stream, now 30 pAInt streamed monthly in real-time
• preview before posting: view multiple images based on your text prompt, then choose the best to post (coming soon)
• option to keep prompts private from other users (coming soon)
• more to come

When a user buys a PRO subscription, an event is sent from Stripe to a webhook endpoint on the AxelART API. This triggers the 2 transactions (via Gelato Relay) to deploy an NFT contract for the user and to increase the stream to 30 pAInt per month. Additionally, as an "upgrade bonus", 10 pAInt are airdropped to the PRO user's Safe at the time of the upgrade. From this point forward, the user's images are minted to their own contract/collection, which contains only their own artwork.

When a PRO subscription is cancelled, another event webhook automatically triggers a transaction to reduce the stream back to 3 pAInt per month and flip the user back to minting on the shared NFT contract.

There are three main categories of code for AxelART:

• Frontend Client App
• Server APIs and Datastore
• Ethereum Smart Contracts

The live demo of the front end AxelART app is located at https://axelart.xyz. The app includes javascript code that primarily interfaces with AxelART server API endpoints.

The javascript web3auth SDK is used in the frontend to power all forms of authentication. Using web3 auth, the user can choose to login with social apps (ie. Twitter/Facebook), email, or wallet (ie. Metamask/WalletConnect). The web3auth SDK interfaces with the nodes in the Auth Network to produce an app-specific private key for the user. The private key exists only in the browser and it never sent to AxelART servers nor saved by any third party. The web3auth SDK also produced a JWT auth token, that is used by AxelART as an API key when calling authenticated AxelART API endpoints (see more below).

The frontend uses the Firebase Firestore SDK to fetch and render AxelART data stored in a Firestore data store: data about users, posts, followers, social reactions, etc.

The HTML and CSS of the AxelART frontend was built using the Instello Ultimate Photo Sharing HTML Template set, used under license.

The frontend is hosted using Firebase Hosting. The frontend code can be found in the repo at server/hosting/.

AxelART uses three core services from Google Firebase for server-side functions.

• Firestore. Data about users and posts are store in a noSQL Firestore datastore.
• Storage. Once images have been generated via OpenAI SDK, they are stored using Firebase Storage (Google Cloud Storage)
• Firebase Functions There are three types of serverless functions.
  • The first is an HTTPS function that handles requests to the AxelART API endpoints, used to access and modify Firestore data and interact with Ethereum smart contracts.
  • Next there are several functions that are triggered by adding or updating data in the Firestore database, which in turn may trigger interactions with the Safe and Gelato SDKs to execute functions onchain.
  • Finally, there are several "cron" functions that run periodically. These poll the Gelato Relay API or Axelar SDK for the status of transactions that have been relayed to Gelato or transported via Axelar GMP. Once Gelato reports that a transaction has been executed, the transaction is fetched using EthersJS and relevant data is extracted from the event logs, such as the tokenId of a newly minted NFT, or the nftContract address of a newly deployed AIrtNFT contract for a PRO user.

Three smart contracts were written in Solidity:

• AIrtNFT.sol - This is an ERC721 NFT smart contract, leveraging OpenZeppelin contracts. A notable inclusion is the support for ERC2771Context which enables secure permission-based function calls via Gelato Relay. Also added are two minting functions which power minting of new images, collecting and transferring pAInt or WETH tokens when necessary.
• Transporter.sol - This Transport contract sends and receives NFTs from multiple AIrtNFT.sol contracts between chains, using GMP on the Alexar Network.
• AIrtNFTFactory.sol - This a factory contract used to deploy minimal Clones of the AIrtNFT.sol and Transporter.sol contracts. This contract was used to deployed the main NFT contract that is shared by FREE users, and also used to deploy NFT contracts for each PRO user when they upgrade. Fun fact: Using the minimal clone approach, it actually costs less gas to deploy an NFT contract for a PRO user, compared to minting an AxelART NFT!. The factory contract is also used to deploy a single instance of Transporter.sol on each chain.
• Streamer.sol - This contract uses the Superfluid protocol to enable streaming of the pAInt utility token, which was also deployed by this contract at deployment time. The core function of the streamer contract enables the starting, updating or stopping of a pAInt stream to a recipient, while optionally dropping some pAInt immediately (not streamed). This contract is only deployed to the home chain.

Note all equivalent contracts are deployed to the same address on each chain. The implementation contracts for AIrtNFT.sol and Transporter.sol as well as the AIrtNFTFactory.sol contracts were actually deployed on all chains via the Multichain Deployer contract on the home chain (Goerli for the live demo). Multichain Deployer is a separate project -- powered by Axelar -- that enables remote deployment of contracts to multiple chains at the same address on each.

• (Shared) AIrtNFT contract: 0x6a531B4447fB07b10A39E99Fc25b9c2cA63eAA42: Goerli - Optimism - Arbitrum
• Transporter contract: 0xa64904acF704926e8032900627a5486Ee191aFe3: Goerli - Optimism - Arbitrum
• AIrtNFTFactory contract: 0xB67E29f515106311703c793B98C7459e3198e053: Goerli - Optimism - Arbitrum
• Streamer contract: 0x83D4A49b80Af1CE060361A457a02d057560A9aD9: Goerli
• pAInt Super Token: 0xB66cf6eAf3A2f7c348e91bf1504d37a834aBEB8A Goerli
• Example PRO AirNFT contract deployed using the factory contract via Gelato Relay: https://goerli.etherscan.io/address/0x5c73f6b7f56137f2c963a3534a0529e63a0b311f: Goerli - Optimism - Arbitrum

Note: the "Transactions" tab on Etherscan may show as empty for some of the above contracts. This is because almost all transactions are executed via Gelato Relay. As such, you can view the "Internal Transactions" tab to view the activity on these contracts.

Here are some quick links to code in this repo, including some examples of where hackathon sponsor tech was used:

• Contracts
• Frontend
• AxelART API
• Server cron functions
• Server DB Triggers
• Axelar GMP (Solidity): sending, receiving/executing
• Axelar SDK: estimate gas, check status
• web3auth SDK: client, server-side JWT verification
• Safe SDK: deploy/predict Safe address, send Safe transaction
• Gelato Relay SDK: update Superfluid stream, mint NFT, deploy contract via Factory, poll API for task status
• Superfluid: streaming contract, update Superfluid stream via Gelato Relay
• Stripe: frontend redirect user to Stripe payment link, server-side Stripe webhook handler
• OpenAI SDK: generate AI image

AxelART was born as AIrtist, a submission to the Safe Account Abstraction hackathon in March 2023. While the vision was always to support interchain NFTs, the initial scope at the time supported only single-chain tokens. Interchain support, powered by Axelar, was added duing the Axelar x Flipside hackathon in May 2023. The name was changed in honor of the sponsor Axelar ... and ... also because nobody knew how to pronounce "AIrtist".

• 2023 Q3 - Team formation. AxelART has been a solo project to date. To take to the next level, skilled and motivated co-founders are needed!
• 2023 Q3 - Seed funding. To be used for team hires when appropriate, mobile app development, cloud computing, and sponsored gas costs.
• 2024 Q1 - Production Interchain launch on Etheruem, Optimism, Arbitrum, Avalanche, BNB, Base, and others

• Further development of PRO premium features:
  • Art generation tools
  • Open Edition NFTs
  • NFT auctions
• Mobile apps for iOS and Android
• Integration with web3 social (Lens, Farcaster, etc.)
• Better support for web3-native users (use own wallet instead of Safe, on-chain Subscriptions, etc.)

• Try it now: https://axelart.xyz (minting on Goerli, Optimism-Goerli, and Arbitrum-Goerli testnets)
• Slide Presentation
• Demo Video: https://youtu.be/sjy7F5azLRQ

• Twitter: @mthacks
• Farcaster: @markcarey
• Discord: @markcarey#5670
• Github: @markcarey