> ## 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.

# Transaction states

> Learn about the different states for deposits, withdrawals, and transfers

## Deposit states

Deposits represent funds received into a subaccount, either through wire
transfers or blockchain transactions.

| State | Description |
| - | - |
| `pending` | The deposit has been detected and is being processed. For wire deposits, the funds are being received. For crypto deposits, the transaction is awaiting blockchain confirmation. |
| `complete` | The deposit has been fully processed and the stablecoin balance has been credited to the subaccount. |
| `failed` | The deposit could not be processed. This can occur if a wire transfer is rejected or a blockchain transaction fails. |

For details on EEA inbound and outbound transfer controls, see
[EEA API behavior](/digital-asset-accounts/references/eea-api-behavior).

## Withdrawal states

Withdrawals redeem stablecoins from a subaccount and send fiat to a linked bank
account through a wire transfer.

| State | Description |
| - | - |
| `pending` | The withdrawal has been initiated and is being processed. The stablecoin amount is held from the available balance while it's redeemed and sent. |
| `complete` | The withdrawal has been fully processed and the fiat has been sent. |
| `failed` | The withdrawal could not be processed. The held funds are returned to the available balance. |

## Transfer states

Transfers represent outbound crypto movements to external blockchain addresses.

| State | Description |
| - | - |
| `pending` | The transfer has been initiated and is being screened, broadcast, or awaiting blockchain confirmation. |
| `complete` | The blockchain transaction has been confirmed and the transfer is finished. |
| `failed` | The transfer could not be completed, for example because risk screening declined it. The funds are returned to the available balance. |

<Note>
  **Transfers vs. withdrawals for crypto operations**: A *transfer* sends
  stablecoins to an external blockchain address without converting to fiat. A
  *withdrawal* redeems stablecoins for fiat currency and sends the fiat through a
  wire transfer. Outbound crypto operations use the transfer endpoint, while
  outbound fiat operations use the withdrawal endpoint.
</Note>

## Internal transfer states

Internal transfers move funds between subaccounts in the same program.

| State | Description |
| - | - |
| `complete` | The internal transfer completed instantly. Both the source and destination balances have been updated. |
| `failed` | The internal transfer could not be processed, typically due to insufficient funds. |

<Note>
  Terminal states (`complete`, `failed`) are final states that transactions cannot
  transition out of. Set up
  [webhook notifications](/api-reference/webhook-endpoints#v2-notifications) to
  receive real-time updates when transactions reach these states.
</Note>

## Notification events

When a transaction reaches a new state, Digital Asset Accounts sends a webhook
that carries the current state. Each category maps to a v2 event type.

| Category | Notifications | Event type |
| - | - | - |
| Deposits | Deposit pending, deposit complete, deposit failed | `mint.deposits` |
| Withdrawals | Withdrawal pending, withdrawal complete, withdrawal failed | `mint.payout` |
| Transfers | Transfer pending, transfer complete, transfer failed | `custody.transfer` |
| Internal transfers | Internal transfer complete | `custody.transfer` |
| Wire events | Wire deposit received, wire withdrawal initiated | `mint.wire` |

For the full event catalog and example payloads, see the Digital Asset Accounts
[Webhooks reference](/api-reference/digital-asset-accounts). To subscribe, see
[Set up a webhook endpoint](/api-reference/webhook-endpoints#v2-notifications).