feat: gas abstraction

docs/walletkit/android/gas-abstraction.mdx

@@ -0,0 +1,72 @@
+# Gas Abstraction (experimental)
+
+WalletKit provides a toolkit for wallet developers to integrate verifying paymaster gas abstraction into their wallets.
+
+`GasAbstractionClient` is instantiated with some basic RPC URL and API key information. This client is long-lived and should be reused between transactions as it will reuse network connections for improved latency.
+
+When receiving a transaction request, send the transaction to the `prepare_gas_abstraction(txn)` method. This will do some thinking and will prepare a set of operations and return a couple of hashes to be signed.
+
+The operations are:
+
+1. Deploying the 7702 account and delegating to it, if needed
+2. Sending a sponsored UserOperation for the initial transaction.
+
+The user will then approve signatures for these operations and the wallet will then call `execute_transaction(txn, signatures)` with the same initial transaction and the signatures.
+
+The function will send the transactions and return status information of them to you.
+
+The below is an example psudo-Rust code of the usage of `GasAbstractionClient`:
+
+```rust
+async fn main() {
+    let eoa = LocalSigner::random();
+    let client = GasAbstractionClient::new(...);
+    let txn = Transaction { to: vitalik.eth, amount: 1 ETH };
+
+    let PreparedGasAbstraction {
+        hashes_to_sign,
+        fields
+    } = client.prepare_gas_abstraction(txn).await?;
+
+    ask_user_for_approval(fields).await?;
+
+    let signatures = hashes_to_sign.iter().map(|hash| account.sign(hash)).collect();
+
+    let receipt = client.execute_transaction(txn, Params {
+        signatures
+    }).await?;
+
+    display_success(receipt)
+}
+```
+
+```rust
+impl GasAbstractionClient {
+    /// Just provide a project ID
+    async fn new(project_id: String) -> Self;
+
+    /// Or you can make chain-specific clients if you want to do it manually
+    async fn new(chain_id: Caip10, rpc_url: Url, bundler_url: Url, paymaster_url: Url) -> Self;
+
+    // Prepare and send gas-abstracted transactions
+    async fn bool prepare_gas_abstraction(Transaction transaction) -> PreparedGasAbstraction;
+    async fn bool execute_transaction(Transaction transaction, params: Params) -> B256;
+
+    // Signature creation
+    async fn ..... COPY signature creation functions from current SDK
+
+    // == Future APIs ==
+    async fn send_user_operation(?) - ?;
+    async fn create_smart_session(?) -> ?;
+}
+
+enum PreparedGasAbstraction {
+    hashes_to_sign: Vec<B256>,
+    fees: GasAbstractionFees, // similar to RouteUiFields -> fee and other UI info for user display
+}
+
+enum Params {
+    /// EOA signatures by the transaction's sender of `hashes_to_sign`
+    signatures: Vec<Signature>,
+}
+```

docs/walletkit/features/gas-abstraction.mdx

@@ -0,0 +1,76 @@
+import Wrapper from '../../components/Home/Wrapper'
+
+import androidLogo from '../../../static/assets/home/androidLogo.png'
+import iosLogo from '../../../static/assets/home/iosLogo.png'
+import rnLogo from '../../../static/assets/home/rnLogo.png'
+import flutterLogo from '../../../static/assets/home/flutterLogo.png'
+import csharpLogo from '../../../static/assets/home/csharpLogo.png'
+import javascriptLogo from '../../../static/assets/home/javascriptLogo.png'
+
+# Gas Abstraction for EOAs (experimental)
+
+Gas Abstraction enables existing EOA accounts to execute transactions without needing to have special tokens to pay for the transaction gas; for example ETH on Ethereum. This solution provides wallet developers with a toolkit to integrate gas abstraction using WalletKit.
+
+## How it works
+
+When your wallet receives a `wallet_sendTransaction` request, the wallet will automatically sponsor the transaction for the user using the Reown paymaster. Native gas tokens are not needed.
+
+This works by upgrading the EOA to a smart account that supports verifying paymasters and sending a sponsored User Operation. Specifically, a 7579 modular Safe smart account is deployed and delegated to in a 7702 transaction. The smart account has the same address as the EOA, and the EOA is the only signer on the account.
+
+## Get Started
+
+<Wrapper
+  type="large"
+  fit={false}
+  items={[
+    {
+      name: 'Android',
+      type: 'android',
+      description: 'Get started with WalletKit in Android.',
+      icon: androidLogo,
+      href: '../android/gas-abstraction'
+    },
+    // {
+    //   name: 'iOS',
+    //   type: 'ios',
+    //   description: 'Get started with WalletKit in iOS.',
+    //   icon: iosLogo,
+    //   href: '../ios/gas-abstraction',
+    //   isWhite: true
+    // },
+    // {
+    //   name: 'React Native',
+    //   type: 'react-native',
+    //   description: 'Get started with WalletKit in React Native.',
+    //   icon: rnLogo,
+    //   href: '../react-native/gas-abstraction'
+    // }
+  ]}
+/>
+
+## FAQ
+
+### What are the available networks for Gas Abstraction?
+
+Gas Abstraction is available on any network where 4337 bundlers and paymasters are available.
+
+Click [here](/) to see what networks the Reown paymaster supports for seamless operation.
+
+### What types of paymasters are supported?
+
+Only verifying paymasters are currently supported (by default the Reown paymaster). ERC-20 paymasters are not yet supported.
+
+### What are the limitations?
+
+- Accounts that already have 7702 delegations will be rejected and are not supported.
+- Because delegation cannot be removed (only changed), the account will need to indefinitely support EIP-1271 signature creation & validation. This is because apps assume if an account has code, that it is a smart account and it will use EIP-1271 to validate the signature.
+
+### What apps does this support?
+
+Any app that supports smart contract accounts. Specifically, EIP-1271 must now be used for signing.
+
+### Are more smart account features available or just gas abstraction?
+
+In the future more features will be supported such as:
+- Sending user operations directly instead of transactions
+- Smart sessions

sidebars.js

@@ -305,6 +305,11 @@ module.exports = {
                   label: 'Chain Abstraction',
                   id: 'walletkit/features/chain-abstraction'
                 },
+                {
+                  type: 'doc',
+                  label: 'Gas Abstraction (experimental)',
+                  id: 'walletkit/features/gas-abstraction'
+                },
                 { type: 'doc', label: 'Notifications', id: 'walletkit/features/notifications' },
                 { type: 'doc', label: 'Verify', id: 'walletkit/features/verify' }
               ]