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Documentation Index

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Circle’s User-Controlled Wallets client SDKs let you embed user-controlled wallets directly in your web and mobile applications. The SDKs handle key management, authentication, confirmation UIs, and signing flows so that the user’s keyshares never leave the user’s device. They pair with a server-side SDK or direct API integration that orchestrates wallet operations from your backend.

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Choose your platform

Web SDK

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iOS SDK

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Android SDK

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React Native SDK

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How it works

A client SDK call flows through Circle’s APIs using a challenge ID that the user authorizes on-device:
  1. A user performs a wallet action in your application—for example, initiating a USDC transfer.
  2. Your server requests the action through Circle’s User-Controlled Wallets REST APIs.
  3. The API returns a response containing a challengeId. The challenge must be completed before the action executes.
  4. Your server passes the challengeId to the client SDK. The SDK prompts the user to authorize the action.
  5. The user authorizes by entering their PIN, completing biometric verification, or confirming on a Confirmation UI. The SDK encrypts the input and delivers it to Circle.
  6. Circle sends a webhook callback (or your server polls the corresponding GET endpoint) with the action’s status.
  7. Your application notifies the end user that the action is complete.

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Security

Keyshares remain exclusively on the user’s device and are never exposed to your server or to Circle. The SDKs encrypt all request bodies in transit. The user retains full control of their assets—neither your application nor Circle can access funds without the user’s authorization.

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UI customization

Each platform SDK ships with prebuilt UIs for PIN entry, security questions, transaction confirmation, and message signing. Override colors, copy, layout, and component styling to match your brand:

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Server-side companion

The client SDK pairs with a server-side SDK that orchestrates wallet operations from your backend. Use the Node.js or Python server SDK to create challenges, manage wallet sets, and integrate with Circle’s APIs: