> ## 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.

# Supported blockchains

> Supported blockchains for Circle Wallets, including account types, token standards, and API limitations.

Circle Wallets supports multiple blockchains. Account type support, token
standards, and API coverage vary by blockchain.

## Supported blockchains by wallet type

The following table lists supported blockchains by wallet type, including the
chain code for each mainnet and testnet environment. Each cell shows which
account types a wallet product supports on a specific blockchain:
[Externally Owned Account (EOA)](/wallets/account-types#externally-owned-accounts-eoa),
[Smart Contract Account (SCA)](/wallets/account-types#smart-contract-accounts-sca-and-msca),
and
[Modular Smart Contract Account (MSCA)](/wallets/account-types#smart-contract-accounts-sca-and-msca).
For more information about wallets and accounts, see
[Choose your wallet and account types](/wallets/account-types).

<Note>
  For "Other EVM blockchains" (for example, BNB Smart Chain), create wallets using
  the `EVM` or `EVM-TESTNET` chain code. Wallet addresses are consistent across
  all EVM-compatible blockchains. See
  [Unified wallet addressing across EVM chains](/wallets/unified-wallet-addressing-evm).

  Only EOA wallets are supported. See
  [Blockchain-specific limitations](#blockchain-specific-limitations) for the full
  list of Wallets API constraints on "Other EVM blockchains."
</Note>

| Blockchain (mainnet / testnet chain code) | Developer-controlled | User-controlled | Modular |
| - | - | - | - |
| Aptos (`APTOS` / `APTOS-TESTNET`) | EOA | EOA | — |
| Arbitrum (`ARB` / `ARB-SEPOLIA`) | EOA, SCA | EOA, SCA | MSCA |
| Arc (`ARC` / `ARC-TESTNET`) | EOA, SCA | EOA, SCA | MSCA |
| Avalanche (`AVAX` / `AVAX-FUJI`) | EOA, SCA | EOA, SCA | MSCA |
| Base (`BASE` / `BASE-SEPOLIA`) | EOA, SCA | EOA, SCA | MSCA |
| Ethereum (`ETH` / `ETH-SEPOLIA`) | EOA, SCA | EOA, SCA | — |
| Monad (`MONAD` / `MONAD-TESTNET`) | EOA, SCA | EOA, SCA | MSCA |
| NEAR (`NEAR` / `NEAR-TESTNET`) | [Signing only](#blockchain-specific-limitations) | — | — |
| Optimism (`OP` / `OP-SEPOLIA`) | EOA, SCA | EOA, SCA | MSCA |
| Polygon PoS (`MATIC` / `MATIC-AMOY`) | EOA, SCA | EOA, SCA | MSCA |
| Solana (`SOL` / `SOL-DEVNET`) | EOA | EOA | — |
| Unichain (`UNI` / `UNI-SEPOLIA`) | EOA, SCA | EOA, SCA | MSCA |
| Other EVM (`EVM` / `EVM-TESTNET`) | [Signing only](#blockchain-specific-limitations) | [Signing only](#blockchain-specific-limitations) | — |

## Supported tokens and standards

* **Aptos**: native coin, Fungible Asset
* **EVM-compatible blockchains**: native coin, ERC-20, ERC-721, and ERC-1155
* **Solana**: native coin, SPL

## Blockchain-specific limitations

Every [Wallets API](/api-reference/wallets) endpoint is available on all
supported blockchains, except for the blockchains listed in the following
sections.

* **Aptos**:
  * NFT lookup is not supported.
  * Balance queries return tokens in primary storage only. Tokens in secondary
    storage
    ([AIP-21](https://github.com/aptos-labs/aptos-core/releases/tag/aptos-node-v1.5.0))
    are excluded.
  * Contract execution
    ([developer-controlled](/api-reference/wallets/developer-controlled-wallets/create-developer-transaction-contract-execution),
    [user-controlled](/api-reference/wallets/user-controlled-wallets/create-user-transaction-contract-execution-challenge))
    is limited to batch transfers. The `abiFunctionSignature` and
    `contractAddress` fields must use fixed values. The following request body
    shows the required values (`entitySecretCiphertext` is required for
    developer-controlled wallets only).

    ```json JSON theme={null}
    {
      "idempotencyKey": "{{$YourUUID}}",
      "walletId": "639ff7f1-2fed-5de4-9976-c1706ca1ef88",
      "feeLevel": "MEDIUM",
      "abiFunctionSignature": "aptos_account::batch_transfer_fungible_assets(metadata:object::Object<fungible_asset::Metadata>,recipients:vector<address>,amounts:vector<u64>)",
      "abiParameters": [
        "0x69091fbab5f7d635ee7ac5098cf0c1efbe31d68fec0f2cd565e8d168daf52832",
        [
          "0xe78568bcfc30070fae04c1c4ba267eecc228e077672e18086baa042cbfb0ba70",
          "0xb8019c3e505fafe00edd1ba95c34f3f78e957da668c23ecb56ccd3a59ee8f21e"
        ],
        ["1", "1"]
      ],
      "contractAddress": "0x1",
      "refId": "aptos-testnet-contractExecution",
      "entitySecretCiphertext": "{{entity-secret-ciphertext}}"
    }
    ```

* **Arbitrum**: Accelerate and cancel transactions are not supported.

* **NEAR**: Developer-controlled wallets support signing only
  ([sign transaction](/api-reference/wallets/developer-controlled-wallets/sign-transaction)
  and
  [sign delegate action](/api-reference/wallets/developer-controlled-wallets/sign-delegate-action)).
  Transfers, balances, NFT lookup, and contract execution are not supported.
  User-controlled wallets are not supported.

* **Other EVM blockchains**: Developer-controlled and user-controlled wallets
  support wallet creation and signing. Circle returns the signed transaction,
  but you are responsible for broadcasting it to the network and managing the
  full transaction lifecycle, including transaction monitoring and balance
  retrieval. Transfers through the Wallets API, contract execution, accelerate,
  and cancel are not supported.

* **Solana**:
  * Contract execution is not supported. Signing typed data is not supported.
    Accelerate and cancel transactions are not supported.
  * SPL token transfers require the recipient to have an Associated Token
    Account (ATA): see
    [Create and fund a Solana ATA](/wallets/gas-station/create-solana-ata) and
    [Solana ATA sponsorship](/wallets/gas-station/solana-ata-sponsorship).

    <Warning>
      Circle Wallets on Solana only support ATAs. Transactions involving non-ATA
      accounts are not parsed, and tokens sent to such accounts may be
      permanently lost.
    </Warning>