> ## 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.

# Gas Station

Gas Station enables developers to build experiences that abstract gas - both for
end-users and developers. Developers can sponsor network fees for the end-user,
removing the need for end-users to hold native tokens in their wallets. The
sponsored gas fees are charged to the developer's credit card; hence, not having
them to hold native tokens across chains. This abstracts gas fees: one of the
biggest problems of building blockchain apps.

## Problem with gas fees

Blockchains require gas transaction fees to incentivize validators and protect
networks against denial of service attacks. The mechanics for these fees have
traditionally been built into the blockchain itself, often requiring gas fees to
be paid in native tokens and sourced by the address that initiated the
transaction.

The experience of sourcing native tokens by the originating wallet makes it hard
for users to interact onchain and limits the usability of blockchain
applications. Depending on the blockchain, there can be different ways to
abstract gas. For example:

1. On EVM chains: With the introduction of
   [ERC-4337](https://eips.ethereum.org/EIPS/eip-4337) (account abstraction),
   there is a way to pay network fees in non-native tokens via smart contracts
   called paymasters
2. On Solana: By using the concept of fee-payers, third party wallets can pay
   for gas on behalf of a user.

## Circle's Gas Station solution

Circle's Gas Station utilizes paymasters (on EVM) and fee-payers (on Solana) to
create a solution that completely abstracts gas. Circle has deployed paymaster
smart contracts and fee-payer wallets that developers can use with Circle
Wallets.

The solution has the following components:

1. **Gas Sponsor:** A third party smart contract or wallet that pays on-chain
   gas fees according to the sponsorship conditions.
   1. Paymaster (EVM): Smart contract (ERC-4337 standard)
   2. Fee-Payer (Solana): Wallets that pay gas fees
2. **Policy:** Let developers set up custom rules and limits on the blockchains
   they want to sponsor.
3. **Billing:** Let developers pay all the gas fees using their preferred
   payment modes (cards).

On EVM chains, the Programmable Wallet must be an ERC-4337-compliant smart
contract account. Developers can create these wallets by passing
`"accountType": "SCA"` in the create wallet API for Wallets.

To learn more on creating a SCA wallet follow one of the two guides:

1. [Create your first developer-controlled wallets](/wallets/dev-controlled/create-your-first-wallet).
2. [Create your first user-controlled wallet](/sdks/user-controlled/react-native-sdk-ui-customization-api).

On Solana, Gas Station can
[sponsor](/wallets/gas-station/solana-ata-sponsorship) the rent deposit for
ATAs, or you can
[create and fund an ATA yourself](/wallets/gas-station/create-solana-ata).

## Supported blockchains

Circle Gas Stations support the following blockchains:

| Blockchain Network | PW User-Controlled | PW Developer Controlled |
| :- | :- | :- |
| Aptos Mainnet | ✅ | ✅ |
| Aptos Testnet | ✅ | ✅ |
| Arbitrum Mainnet | ✅ | ✅ |
| Arbitrum Sepolia Testnet | ✅ | ✅ |
| Arc Mainnet | ✅ | ✅ |
| Arc Testnet | ✅ | ✅ |
| Avalanche Mainnet | ✅ | ✅ |
| Avalanche Fuji Testnet | ✅ | ✅ |
| Base Mainnet | ✅ | ✅ |
| Base Sepolia Testnet | ✅ | ✅ |
| Ethereum Mainnet | ✅ | ✅ |
| Ethereum Sepolia Testnet | ✅ | ✅ |
| Monad Mainnet | ✅ | ✅ |
| Monad Testnet | ✅ | ✅ |
| Optimism Mainnet | ✅ | ✅ |
| Optimism Sepolia Testnet | ✅ | ✅ |
| Polygon Mainnet | ✅ | ✅ |
| Polygon Amoy Testnet | ✅ | ✅ |
| Solana Mainnet | ✅ | ✅ |
| Solana Devnet | ✅ | ✅ |
| Unichain Mainnet | ✅ | ✅ |
| Unichain Sepolia Testnet | ✅ | ✅ |

## Related products

Gas Station allows you to sponsor network fees for your users. If you want to
allow users to pay their network fees with USDC themselves, see the
[Circle Paymaster](/paymaster).

### Comparison with Circle Paymaster

| Category | Circle Paymaster | Gas Station |
| - | - | - |
| **Description** | A permissionless smart contract that allows users to pay gas fees in USDC instead of native tokens. | A feature of Wallets that allows developers to sponsor gas fees for their users. |
| **Circle account** | Not required | Required |
| **Compatible wallets** | Any ERC-4337-compliant wallet | Circle Wallets |
| **Gas fees paid in** | USDC | Fiat currency via credit card |
| **Pricing model** | 10% of the gas fee | 5% of the gas fee |
| **Paid by** | End user | Developer |