Introduction to Account Abstraction

Learn about Account Abstraction, wallet custody types, and how MSA API empowers developers to build secure wallet solutions.

Account Abstraction (AA) represents a paradigm shift in how wallets work on Ethereum and EVM-compatible blockchains. Instead of relying solely on Externally Owned Accounts (EOAs) controlled by private keys, Account Abstraction enables programmable smart contract wallets with customizable validation logic.

What is Account Abstraction?

Traditional Ethereum accounts have limitations:

Single signature requirement: Only one private key controls the account
Fixed gas payment: Only ETH can be used to pay for gas
Limited recovery options: Lose your private key, lose your wallet
Poor UX: Complex transaction signing flow

Account Abstraction solves these problems by making wallets programmable smart contracts that can:

Use multiple signature schemes (ECDSA, passkeys, multi-sig)
Pay gas with any ERC-20 token via paymasters
Implement custom recovery mechanisms
Batch multiple operations into a single transaction
Provide familiar Web2-like user experiences

How MSA API Works

The MSA API abstracts the complexity of Account Abstraction, providing developers with simple REST endpoints to:

1. Create Wallets

Deploy smart contract wallets with various custody options:

// Using API HTTP (fetch) for wallet creation
const response = await fetch('https://api.msa.omnes.tech/create', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    accounts: [{
      walletCustody: 3, // ECDSA_PASSKEY_VALIDATOR
      salt: "user@example.com",
      passkeyPubKey: ["base64-encoded-key"]
    }],
    settings: { /* ... */ }
  })
});
const wallet = await response.json();

2. Execute Transactions

Send UserOperations through the Entry Point contract:

// Using SmartWallet SDK for transaction execution
import { PKSigner, SmartWallet, AccountOperations, Operation } from '@omnes/smartwallet-ts-sdk';

const signer = await PKSigner.create(privateKey as `0x${string}`);
const smartWallet = await SmartWallet.create(
    signer.signMessage,
    signer.signMessage,
    signer.getEVMAddress(),
    rpcURL,
    apiKey
);

const operations: Operation = {
    to: "0x...", // Token contract
    value: BigInt(0),
    funcSignature: "transfer(address,uint256)",
    params: ["0x...", 1000000000000000000] // 1 token
};

const accountOperations: AccountOperations[] = [{
    account: {
        walletCustody: 1,
        salt: "user@example.com",
        publicKeys: []
    },
    operations: [operations],
    settings: {}
}];

const result = await smartWallet.buildAndRequestSendUserOperations(
    accountOperations,
    [],
    []
);

3. Manage Security

Configure validators, signers, and recovery mechanisms:

// Add a new signer to a multisig wallet
const result = await msaClient.addSigner({
  to: walletAddress,
  funcSignature: "addSigner(address,(bool,bool,bool,bool))",
  funcParams: [
    newSignerAddress,
    [true, true, true, true] // Permissions
  ]
});

Standard ECDSA signature validation
Similar to traditional wallets
Good for simple use cases

2. ECDSA_PASSKEY_VALIDATOR (Hybrid)

Combines ECDSA signatures with passkey authentication
Enhanced security through biometric verification
Ideal for consumer applications

3. PASSKEY_VALIDATOR (Biometric)

Pure passkey-based authentication
No private keys to manage
Perfect for Web2-native experiences

4. MULTISIG_VALIDATOR (Shared Control)

Traditional M-of-N multi-signature setup
Shared custody between multiple parties
Essential for organizational use

5. MULTISIG_PASSKEY_VALIDATOR (Enterprise)

Multi-signature with passkey support
Maximum security for high-value scenarios
Combines shared control with biometric auth

Entry Points and UserOperations

Account Abstraction uses a standardized flow:

UserOperation: A structure containing transaction intent
Entry Point: Smart contract that validates and executes UserOperations
Bundler: Service that submits UserOperations to the Entry Point
Paymaster: Optional contract that sponsors gas payments

graph LR
    A[User Intent] --> B[UserOperation]
    B --> C[MSA API]
    C --> D[Bundler]
    D --> E[Entry Point]
    E --> F[Smart Wallet]
    F --> G[Target Contract]