> **Can't find what you're looking for?** Use `search_docs` on the docs MCP server at `https://v3.viem.sh/api/mcp` to find what you need.

# Migrate from v2

The v3 API groups actions by resource, moves constructors into module namespaces, and rebuilds ERC-4337 primitives on ox-backed namespaces.

## Clients and Accounts

| v2 | v3 |
| --- | --- |
| `createBundlerClient(options)` | `BundlerClient.create(options)` |
| `createPaymasterClient(options)` | `PaymasterClient.create(options)` |
| `toSmartAccount(implementation)` | `SmartAccount.from(implementation)` |
| `toCoinbaseSmartAccount(options)` | `CoinbaseSmartAccount.from(options)` |
| `toSoladySmartAccount(options)` | `SoladySmartAccount.from(options)` |
| `toSimple7702SmartAccount(options)` | `Simple7702SmartAccount.from(options)` |
| `toWebAuthnAccount({ credential, getFn, rpId })` | `WebAuthnAccount.fromCredential(credential, { getFn, rpId })` |
| `createWebAuthnCredential(options)` | `WebAuthn.createCredential(options)` from `viem/utils` |

## Actions

Import `Actions` from `viem/erc4337`, or call the same methods on a Bundler or Paymaster Client.

| v2 | v3 |
| --- | --- |
| `prepareUserOperation` | `Actions.userOperation.prepare` |
| `estimateUserOperationGas` | `Actions.userOperation.estimateGas` |
| `sendUserOperation` | `Actions.userOperation.send` |
| `getUserOperation` | `Actions.userOperation.get` |
| `getUserOperationReceipt` | `Actions.userOperation.getReceipt` |
| `waitForUserOperationReceipt` | `Actions.userOperation.waitForReceipt` |
| `getSupportedEntryPoints` | `Actions.entryPoint.getSupported` |
| `getPaymasterData` | `Actions.paymaster.getData` |
| `getPaymasterStubData` | `Actions.paymaster.getStubData` |
| Bundler `getChainId` | Core `Actions.chains.getId` |

## ERC-4337 Primitives

Viem exposes `EntryPoint`, `UserOperation`, `UserOperationGas`, and `UserOperationReceipt` modules from `viem/erc4337`. The `UserOperation` RPC codec uses the Bundler wire field `eip7702Auth`, preserves EntryPoint 0.6 `paymasterAndData`, and carries EntryPoint 0.9 `paymasterSignature`.

| v2 | Replacement |
| --- | --- |
| `getUserOperationHash` | `UserOperation.hash` |
| `getUserOperationTypedData` | `UserOperation.toTypedData` |
| `toPackedUserOperation` | `UserOperation.toPacked` |
| `getInitCode` | `UserOperation.toInitCode` |
| `toUserOperation` | `UserOperation.from` |
| `formatUserOperation` | `UserOperation.fromRpc` |
| `formatUserOperationRequest` | `UserOperation.toRpc` |
| `formatUserOperationGas` | `UserOperationGas.fromRpc` |
| `formatUserOperationReceipt` | `UserOperationReceipt.fromRpc` |
| EntryPoint ABI constants | `EntryPoint.abiV06`, `abiV07`, `abiV08`, and `abiV09` |
| EntryPoint address constants | `EntryPoint.addressV06`, `addressV07`, `addressV08`, and `addressV09` |
| `EntryPointVersion` | `EntryPoint.Version` |

## Removed Experimental APIs

The v2 experimental entrypoints were removed. ERC-7715 `grantPermissions` and ERC-7895 `addSubAccount` have no v3 replacements.

Standalone ERC-7739 helpers were also removed. `SoladySmartAccount.from` keeps ERC-7739 signing private to the implementation for deployed and counterfactual accounts.