> ## 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. # Get Gateway info for supported domains and tokens > Provides information about the API and details of the supported domains and tokens. ## OpenAPI ````yaml openapi/gateway.yaml get /v1/info openapi: 3.0.3 info: title: Circle Gateway version: 1.0.0 description: > Circle Gateway allows you to create a chain-abstracted USDC balance and transfer it instantly to any supported destination chain. servers: - url: https://gateway-api-testnet.circle.com - url: https://gateway-api.circle.com security: [] tags: - name: Gateway description: >- Endpoints for getting a unified USDC balance and creating attestations for transfer - name: Gateway Batch description: Endpoints for batch processing of EIP-3009 authorizations - name: Webhook Subscriptions description: Manage webhook subscriptions for Gateway event notifications. paths: /v1/info: get: tags: - Gateway summary: Get Gateway info for supported domains and tokens description: >- Provides information about the API and details of the supported domains and tokens. operationId: GetGatewayInfo responses: '200': description: Gateway info content: application/json: schema: $ref: '#/components/schemas/InfoResponse' components: schemas: InfoResponse: type: object description: Response containing information about supported domains and tokens properties: version: type: integer description: API version number domains: type: array description: List of supported domains and their contract information items: type: object properties: chain: type: string description: Human-readable chain name example: Ethereum network: type: string description: Human-readable network name example: Sepolia domain: $ref: '#/components/schemas/Domain' description: Domain identifier walletContract: type: object description: Wallet contract information for this domain properties: address: type: string description: Address of the wallet contract supportedTokens: type: array items: $ref: '#/components/schemas/Token' description: List of tokens supported by this wallet contract required: - address - supportedTokens minterContract: type: object description: Minter contract information for this domain properties: address: type: string description: Address of the minter contract supportedTokens: type: array items: $ref: '#/components/schemas/Token' description: List of tokens supported by this minter contract required: - address - supportedTokens processedHeight: type: string description: The latest processed block height for this network example: '8666762' burnIntentExpirationHeight: type: string description: >- The current minimum accepted block height for a burn intent expiration on this network. The value is based on the latest confirmed block. Developers should add some buffer to this value to avoid transfer request failures. example: '8666792' required: - chain - network - domain - processedHeight - burnIntentExpirationHeight required: - version - domains Domain: type: integer enum: - 0 - 1 - 2 - 3 - 5 - 6 - 7 - 10 - 13 - 14 - 16 - 19 - 26 description: | Circle domain identifiers for supported chains: - 0 - Ethereum - 1 - Avalanche - 2 - OP - 3 - Arbitrum - 5 - Solana - 6 - Base - 7 - Polygon PoS - 10 - Unichain - 13 - Sonic - 14 - World Chain - 16 - Sei - 19 - HyperEVM - 26 - Arc Token: type: string description: Supported tokens for Gateway enum: - USDC ````