> ## 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. # List attestations for crosschain transfers > Returns an array of attestations for the specified crosschain transfers, filtered by remote domain. Use the Link header in the response to navigate between pages. ## OpenAPI ````yaml openapi/xreserve.yaml get /v1/remote-domains/{remoteDomain}/attestations openapi: 3.0.2 info: title: Circle xReserve version: 1.0.0 description: > xReserve enables transfers between USDC and USDC-backed tokens across supported blockchain networks using a secure attestation system. servers: - url: https://xreserve-api-testnet.circle.com description: Testnet - url: https://xreserve-api.circle.com description: Mainnet security: [] tags: - name: xReserve description: xReserve endpoints paths: /v1/remote-domains/{remoteDomain}/attestations: get: tags: - xReserve summary: List attestations for crosschain transfers description: > Returns an array of attestations for the specified crosschain transfers, filtered by remote domain. Use the Link header in the response to navigate between pages. operationId: listAttestations parameters: - $ref: '#/components/parameters/RemoteDomain' - $ref: '#/components/parameters/PageSize' - $ref: '#/components/parameters/PageAfter' - $ref: '#/components/parameters/PageBefore' - $ref: '#/components/parameters/From' - $ref: '#/components/parameters/To' responses: '200': $ref: '#/components/responses/AttestationsListResponse' '400': $ref: '#/components/responses/ErrorResponse' '404': $ref: '#/components/responses/ErrorResponse' '500': $ref: '#/components/responses/ErrorResponse' components: parameters: RemoteDomain: in: path name: remoteDomain required: true schema: type: integer minimum: 0 description: The remote domain ID by which to filter results. example: 1 PageSize: in: query name: pageSize required: false schema: type: integer minimum: 1 maximum: 1000 description: The number of results to return per page. example: 50 PageAfter: in: query name: pageAfter required: false schema: type: string description: >- Base64-encoded pagination cursor that returns the next page of results. Do not use with `pageBefore`. PageBefore: in: query name: pageBefore required: false schema: type: string description: >- Base64-encoded pagination cursor that returns the previous page of results. Do not use with `pageAfter`. From: in: query name: from required: false schema: type: string format: date-time description: > Filters results starting from the specified timestamp, in ISO 8601 format. Example: 2025-11-17T23:59:59Z To: in: query name: to required: false schema: type: string format: date-time description: | Filters results up to the specified timestamp, in ISO 8601 format. Example: 2025-11-17T23:59:59Z responses: AttestationsListResponse: description: Successfully retrieved attestations. headers: Link: description: | Provides pagination links for navigating result pages: - `rel="self"`: current page - `rel="first"`: first page - `rel="next"`: next page - `rel="prev"`: previous page schema: type: string example: >- ; rel="self", ; rel="first", ; rel="next" content: application/json: schema: $ref: '#/components/schemas/AttestationsListResponse' ErrorResponse: description: Standard error response. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' schemas: AttestationsListResponse: type: object description: Contains a list of returned attestations. properties: attestations: type: array description: Contains an array of attestations. items: $ref: '#/components/schemas/AttestationObject' required: - attestations ErrorResponse: type: object description: Standard error response. properties: success: type: boolean example: false message: type: string example: Error message AttestationObject: type: object description: Contains attestation data. properties: payload: type: string pattern: ^0x[a-fA-F0-9]*$ description: The encoded attestation payload data. example: '0x123456' messageHash: type: string pattern: ^0x[a-fA-F0-9]{64}$ description: The deposit message hash that identifies the attestation. attestation: type: string pattern: ^0x[a-fA-F0-9]*$ description: The xReserve attestation signature. required: - payload - messageHash - attestation ````