> ## 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.
# xReserve withdrawal fees
Circle collects fees from remote blockchains for withdrawing funds from the
xReserve smart contract.
**Note**: Circle doesn't collect a fee for xReserve deposits. However, users
can still incur gas fees, and the remote blockchain might charge a fee to
process the deposit and mint the corresponding USDC-backed stablecoins.
## Fee types
The following is a list of fees that can occur, depending on the circumstances
of the xReserve withdrawal:
* **xReserve protocol fee**: Applies to every withdrawal unless the destination
is an xReserve source blockchain (Ethereum or Arc).
* **Gateway protocol fee**: Applies if the destination is a Gateway supported
chain other than the source.
* **CCTP protocol fee**: Applies if the destination is a CCTP supported
blockchain that is not supported by Gateway.
* **Gas fee**: Covers the onchain gas for the withdrawal transaction.
* **xReserve forwarding fee**: Applies if the remote blockchain opts for Circle
to forward the attestations on the source or destination blockchain.
* **Forwarding gas fee**: Covers the destination chain gas for the forwarding
transaction if forwarding the withdrawal.
Because Ethereum and Arc are both xReserve source blockchains, withdrawals
delivered to either blockchain are treated as same-chain and don't incur an
xReserve protocol fee, regardless of which source blockchain funds the
withdrawal. This waiver is specific to xReserve; Gateway fee behavior is
unchanged.
## Table of fees
The following table shows the fees by destination blockchain.
| Destination blockchain | xReserve protocol fee (bps) | Gateway protocol fee (bps) | CCTP protocol fee (bps) | Gas fee (USDC) |
| - | - | - | - | - |
| Arbitrum | 1 | 0.5 | N/A | 2 |
| Arc | None | N/A | N/A | 0.0035 |
| Avalanche | 1 | 0.5 | N/A | 2 |
| Base | 1 | 0.5 | N/A | 2 |
| Codex | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Ethereum | None | N/A | N/A | 1 |
| HyperEVM | 1 | 0.5 | N/A | 2 |
| Ink | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Linea | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Monad | 1 | N/A | 0-1 (by transfer speed) | 2 |
| OP | 1 | 0.5 | N/A | 2 |
| Plume | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Polygon PoS | 1 | 0.5 | N/A | 2 |
| Sei | 1 | 0.5 | N/A | 2 |
| Solana | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Sonic | 1 | 0.5 | N/A | 2 |
| Unichain | 1 | 0.5 | N/A | 2 |
| World Chain | 1 | 0.5 | N/A | 2 |
| XDC | 1 | N/A | 0-1 (by transfer speed) | 2 |
| Destination blockchain | xReserve forwarding fee (USDC) | Forwarding gas fee (USDC) |
| - | - | - |
| Arbitrum | \$0.20 | \$0.01 |
| Arc | \$0.01 | \$0.0029 |
| Avalanche | \$0.20 | \$0.02 |
| Base | \$0.20 | \$0.01 |
| Codex | \$1.45 | \$0.50 + destination gas |
| Ethereum | \$0.20 | \$0.80 |
| HyperEVM | \$0.20 | \$0.05 |
| Ink | \$1.45 | \$0.50 + destination gas |
| Linea | \$1.45 | \$0.50 + destination gas |
| Monad | \$1.45 | \$0.50 + destination gas |
| OP | \$0.20 | \$0.0015 |
| Plume | \$1.45 | \$0.50 + destination gas |
| Polygon PoS | \$0.20 | \$0.0015 |
| Sei | \$0.20 | \$0.001 |
| Solana | \$1.45 | \$0.50 + destination gas |
| Sonic | \$0.20 | \$0.01 |
| Unichain | \$0.20 | \$0.001 |
| World Chain | \$0.20 | \$0.01 |
| XDC | \$1.45 | \$0.50 + destination gas |