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Documentation Index

Fetch the complete documentation index at: https://developers.circle.com/llms.txt

Use this file to discover all available pages before exploring further.

Modular wallets are user-controlled smart accounts built on Modular Smart Contract Accounts (MSCA). Users sign with , and you integrate via Circle SDKs for web, iOS, and Android. You can sponsor gas, run batch or parallel transactions, and extend behavior with modules. For a comparison of all wallet products, see Choose your wallet product and account types.

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Key features

User retains custody

Users control their keys via passkeys (WebAuthn). Keys stay on the user’s device; your app never holds them. Optional recovery lets users restore access with a recovery key.

Gasless transactions

Use Gas Station to sponsor network fees so users don’t need native tokens. Set paymaster policies in the Circle Console and pass paymaster: true when sending user operations.

Batch and parallel execution

Send multiple operations in one user op for better UX and efficiency. Use 2D nonces to run independent transactions in parallel. See Modular Wallet Operations for details.

Modules and SDKs

Extend accounts with modules (for example allowlists, automation). Build with the Web, iOS, or Android SDK.

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What you can build

Use modular wallets when you want user-owned keys with a simple onboarding flow. Common use cases:
Onboard users with biometrics or device unlock, with no seed phrases or passwords. Users sign transactions from your app; you orchestrate flows with the modular wallets SDK and never hold keys.
Sponsor gas so users don’t need native tokens. Combine multiple actions (for example approve and transfer) in one user operation, or run independent operations in parallel with 2D nonces.
Add modules to smart accounts for allowlisted transfers or custom logic.
Expose modular wallets as an EIP-1193 provider so other Web3 SDKs (for example Web3.js) can connect to Circle Smart Accounts. See Modular Wallet Operations for the pattern.

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Get started

Passkey and Smart Account

Understand passkey as signer and the Circle Smart Account flow before you run the quickstart.

Create a Modular Wallet

Set up the SDK, register with a passkey, create a smart account, and send a gasless user operation.