> ## 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.

# How-to: Fund your account

> Prepare burn-side and mint-side balances so you can place Match orders.

Funding works differently depending on which side of Match you participate on.
Burn-side participants draw from an existing Circle Mint USDC wallet; no
separate deposit is needed. Mint-side participants wire USD to a Match fiat
account. Circle then converts the received USD to a Match-only USDC balance.
This guide walks through both paths and shows you how to confirm your balance is
ready before placing orders. For background on why these two models exist, see
[Funding model](/circle-match/concepts/funding-model).

## Prerequisites

Before you begin, ensure that you've:

* Obtained a Circle API key with Match access
* Completed onboarding for the participant role you intend to use (burn side,
  mint side, or both)

## Burn-side funding

Burn-side orders are funded by your existing Circle Mint USDC wallet. There is
no separate deposit step. When you place a burn order, Circle reserves the
specified amount from your Mint wallet balance for the duration of the auction
cycle.

Before placing an order, confirm that:

* Your Circle Mint wallet holds at least \$100 USDC (the minimum order size)
* The balance available in your Mint wallet covers the order amount, accounting
  for any USDC already reserved by resting orders

If your available balance is too low when you submit a burn order, the API
returns error `137001` (Insufficient available balance, HTTP 400). Add USDC to
your Circle Mint wallet and retry.

## Mint-side funding

### Step 1. Wire USD to your Match fiat account

Wire USD from your bank to the Match fiat account provided during onboarding.
Circle converts the received USD to a Match-only USDC balance. This USDC is
restricted. It cannot be sent to blockchain addresses. To withdraw it, use a
no-fee withdrawal that burns the USDC and wires USD back to a linked fiat
account.

Wire timing depends on your bank and the time of day. Contact your Circle
account representative if a wire has not settled in the expected window.

### Step 2. Confirm your balance

After the wire settles, call `GET /v1/match/account` to verify that your Match
USDC balance reflects the deposited amount.

```bash theme={null}
curl -X GET https://api-sandbox.circle.com/v1/match/account \
  -H "Authorization: Bearer $API_KEY"
```

The following example shows a successful response:

```json theme={null}
{
  "data": {
    "accountId": "550e8400-e29b-41d4-a716-446655440000",
    "usdc": {
      "available": { "amount": "4000.00", "currency": "USD" },
      "reserved": { "amount": "1000.00", "currency": "USD" },
      "total": { "amount": "5000.00", "currency": "USD" }
    },
    "exposure": {
      "activeOrderCount": 3,
      "mintOrderCount": 2,
      "burnOrderCount": 1
    },
    "activity": {
      "from": "2026-07-18T00:00:00Z",
      "to": "2026-08-17T00:00:00Z",
      "totalMatched": { "amount": "18000.00", "currency": "USD" },
      "rebatesEarned": { "amount": "50.00", "currency": "USD" },
      "feesPaid": { "amount": "0.00", "currency": "USD" }
    }
  }
}
```

**Balance fields:**

| Field | Description |
| - | - |
| `usdc.total` | Your full Match USDC balance, including any amount currently reserved by open orders. Applies to mint-side participants only. |
| `usdc.reserved` | The portion of `usdc.total` held by open resting orders. This amount is not available for new orders. |
| `usdc.available` | `usdc.total` minus `usdc.reserved`. This is the balance you can use when placing new mint orders. |
| `exposure` | Order count breakdown: `activeOrderCount`, `mintOrderCount`, `burnOrderCount`. |
| `activity` | Windowed totals for the reporting period: `totalMatched`, `rebatesEarned`, `feesPaid`. |

<Note>
  The account summary is a best-effort, non-consistent snapshot. `activity`
  figures may lead settlement and are for operational visibility only. For exact
  reconciliation, use your order and settlement records instead.
</Note>

Your `usdc.available` must be at least \$100 before you can place a mint order.
If you call `GET /v1/match/account` before your account is set up, the API
returns error `138003` (HTTP 404). Contact your Circle account representative to
confirm your account is active.

## Error reference

| Code | HTTP | Meaning |
| - | - | - |
| 137001 | 400 | Insufficient available balance. Your available USDC is too low to cover the order amount. |
| 138003 | 404 | No Match wallet found. The entity does not have a Match account. |
| 139001 | 400 | The Match wallet for this account is invalid or unavailable. |