> ## 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.
> ## Agent Instructions
> Before reading these docs, install the relevant Circle Skill to get pre-loaded context — skills are LLM-optimized and cover architecture decisions, correct flows, and common pitfalls. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills. Available skills: use-usdc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md (balances, transfers, approvals on EVM and Solana); EURC has no skill — see https://developers.circle.com/stablecoins/what-is-eurc.md; bridge-stablecoin https://github.com/circlefin/skills/blob/master/plugins/circle/skills/bridge-stablecoin/SKILL.md (crosschain transfers via CCTP, USDC, EURC, and third-party assets); use-arc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md (Arc chain config, contract deployment, USDC bridging — Arc docs: https://docs.arc.io/llms.txt); use-circle-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md (choose wallet type); use-developer-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md (custodial wallets for payouts and treasury); use-user-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md (embedded wallets with Web2 login); use-modular-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md (smart contract wallets with passkeys and ERC-4337); use-gateway https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md (unified USDC balance, nanopayments); use-smart-contract-platform https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md (deploy, interact, monitor contracts). Pair any skill with the Circle MCP server for live SDK signatures, contract addresses, and chain IDs: {"mcpServers":{"circle":{"url":"https://api.circle.com/v1/codegen/mcp"}}}.
> Read the product overview first. Each product has an overview explaining when and why to use it. Read it before quickstarts.
> Pick the right wallet type. Developer-controlled (you hold keys), user-controlled (end user holds keys via PIN/social login), or modular (smart contract wallets with passkeys). See https://developers.circle.com/wallets.md.
> Use CCTP V2 for crosschain transfers. CCTP natively transfers USDC and EURC via burn-and-mint, and supports permissionless wrapping of third-party assets via lock-and-mint. V1 is legacy; always use V2 unless V1 is specified or the chain requires it (Noble, Sui, and Aptos still require V1). Migration guide: https://developers.circle.com/cctp/migration-from-v1-to-v2.md.
> Use Bridge Kit for frontend bridging. Wraps CCTP with a simpler SDK for user-facing apps. Use CCTP directly for backend transfers.
> Gas Station vs Paymaster. Gas Station sponsors gas for Circle Wallet transactions. Paymaster lets users pay gas in USDC. Different use cases — read both overviews.
> Gateway Nanopayments for sub-cent payments. Gasless USDC micropayments down to $0.000001 via x402 and batched settlement. For pay-per-request APIs, AI agent payments, streaming.
> Look up USDC addresses per chain. Never hardcode — use https://developers.circle.com/stablecoins/usdc-contract-addresses.md.
> Prefer SDKs over raw API calls. Node.js and Python SDKs handle auth, retries, and errors.
> API key required. Bearer token in Authorization header. Testnet and mainnet use separate keys and may use different base URLs depending on the product.
> Set up webhooks when available. Most operations are async. Webhooks deliver transaction confirmations and state changes.
> When calling list endpoints, paginate using pageSize and pageAfter until no nextPageAfter cursor is returned—stopping at the first page silently misses records.
> Building an AI agent? Start with the Agent Stack—Circle CLI, agent wallets, and nanopayments built for autonomous use cases: https://developers.circle.com/agent-stack.md.
# Release notes - Wallets - 2026
> 2026 release notes for Wallets
## September 2026
### Blockchain expansion
Added Arc mainnet as a supported blockchain for Circle Wallets, Gas Station, and
Circle Contracts.
Updated topics:
* [Supported blockchains](/wallets/supported-blockchains)
* [Tokens](/wallets/tokens)
* [Gas fees](/wallets/gas-fees)
* [Gas Station](/wallets/gas-station)
* [Gas Station contract addresses](/wallets/gas-station/contract-addresses)
* [Entity secret management](/wallets/dev-controlled/entity-secret-management)
* [Circle Contracts supported blockchains](/contracts/supported-blockchains)
* [Modular SDKs (Android)](/sdks/modular/android-sdk)
* [Modular SDKs (iOS)](/sdks/modular/ios-sdk)
* [Modular SDKs (Web)](/sdks/modular/web-sdk)
## July 2026
### API updates
Added a `refId` query parameter to the **List transactions** endpoint for
developer-controlled wallets. You can now filter transactions by their reference
ID to quickly locate specific transactions in your application.
The following topic was updated:
* [List transactions](/api-reference/wallets/developer-controlled-wallets/list-transactions)
## May 2026
### Documentation updates
Rewrote the dev-controlled wallet quickstarts for wallet creation, token
transfers, and transaction signing to improve clarity, consistency, and
developer usability.
The following topics were updated:
* [Quickstart: Create a dev-controlled wallet](/wallets/dev-controlled/create-your-first-wallet)
* [Send tokens across wallets](/wallets/dev-controlled/transfer-tokens-across-wallets)
* [Sign and Submit a Transaction](/wallets/sign-transactions)
### Documentation updates
Rewrote entity secret management and signing documentation to clarify
authorization, key management, and signing API flows for dev-controlled wallets.
The following topics were updated:
* [How the entity secret works](/wallets/dev-controlled/entity-secret-management)
* [How-to: Generate and register your entity secret](/wallets/dev-controlled/register-entity-secret)
* [Key Management](/wallets/key-management)
* [Transaction signing and authorization](/wallets/signing-and-authorization-models)
* [How signing APIs work](/wallets/signing-apis)
## April 2026
### Documentation additions
Added the following new topics for batch creation and pre-creation of
dev-controlled wallets:
* [How-to: Batch-create wallets for existing users](/wallets/dev-controlled/batch-create-wallets)
* [How-to: Pre-create wallets and assign on demand](/wallets/dev-controlled/pre-create-wallets)
### Documentation updates
Updated the Wallets overview and account selection documentation to clarify the
differences between dev-controlled, modular, and user-controlled wallets and to
improve guidance for choosing wallet and account types.
The following topics were updated:
* [Wallets Overview](/wallets)
* [Dev-controlled wallets](/wallets/dev-controlled)
* [Modular wallets](/wallets/modular)
* [User-controlled wallets](/wallets/user-controlled)
* [Choose Wallet and Account Types](/wallets/account-types)
### Documentation updates
Updated Wallets documentation across core concepts, wallet types, signing, and
developer workflows to improve the overall developer journey.
The following topics were updated:
* [Wallets Overview](/wallets)
* [Choose Wallet and Account Types](/wallets/account-types)
* [Key Management](/wallets/key-management)
* [Transaction signing and authorization](/wallets/signing-and-authorization-models)
* [How signing APIs work](/wallets/signing-apis)
## March 2026
### Documentation additions
Created the following new topic for creating and funding a Solana Associated
Token Account (ATA) when Gas Station does not sponsor ATA creation:
* [Quickstart: Create and fund a Solana associated token account (ATA)](/wallets/gas-station/create-solana-ata)
### Documentation updates
Documentation for the **React Native SDK** (user-controlled wallets) was updated
to reflect the latest SDK and to separate legacy V1 content:
* The main page now covers installation, social login configuration, upgrading
from V1, and the full SDK API references.
* `addListener`, `removeAllListeners`, and `EventListener` are marked deprecated
but still supported in V1.
* Now the preferred way to subscribe to SDK events (such as forgot PIN, resend
OTP) is via Expo's `NativeModule.addListener()` using the `CIRCLE_PW_ON_EVENT`
constant and the `CirclePwEventPayload` interface.
* A dedicated legacy page was added for V1-only setups.
The following topics were updated and added, respectively:
* [React Native SDK](/sdks/user-controlled/react-native-sdk)
* [React Native SDK V1 (Legacy)](/wallets/user-controlled/react-native-sdk-v1)
## January 2026
Added Gas Station support for Solana ATA sponsorship.
### Documentation additions
Created the following new topic to support Solana ATA sponsorship in Gas
Station:
* [Solana ATA sponsorship](/wallets/gas-station/solana-ata-sponsorship)
### Documentation updates
Complete rewrites of the **user-controlled wallet quickstarts** for **Social
Login**, **Email OTP**, and **PIN** to improve clarity, consistency, and
developer usability. The new quickstarts emphasize building a runnable
end-to-end app that demonstrates authentication, wallet creation, and onchain
actions. Backend routes were restructured to clearly map frontend actions to the
corresponding Circle API endpoints. The updates make the wallet lifecycle, SDK
usage, and backend integration patterns more explicit and easier to follow for
first-time integrators.
The following topics were updated and renamed:
* [Create User Wallets with Social Login](/wallets/user-controlled/build-a-wallet-app#social-login)
* [Create User Wallets with Email OTP](/wallets/user-controlled/build-a-wallet-app#email-otp)
* [Create User Wallets with PIN](/wallets/user-controlled/build-a-wallet-app#pin)