> ## 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. # Create daily custody balance report > Creates a daily custody balance report for USDC and EURC and sends it to Circle. For `reportType=eea`, this endpoint represents the four reportable cells of EBA Template S 08.00 for one token and one reference date: CASP total token count and EUR value, plus the EU-client subset token count and EUR value. MiCA / EBA S 08.00 mapping (`reportType=eea`): - S 08.00 Row 0010 / Col 0010 maps to `additionalFields.totalBalance` - S 08.00 Row 0010 / Col 0020 maps to `additionalFields.equivalentEuroTotalBalance` - S 08.00 Row 0020 / Col 0010 maps to `localBalance` - S 08.00 Row 0020 / Col 0020 maps to `additionalFields.equivalentEuroLocalBalance` `localBalance` and `totalBalance` are token-unit counts. `equivalentEuroLocalBalance` and `equivalentEuroTotalBalance` are EUR values. EU clients are determined by habitual residence for natural persons and registered office for legal persons. USD/EUR FX conversion should be based on the ECB rate applicable for that date, as available on the ECB website. Validation rules: - `localBalance` must be less than or equal to `additionalFields.totalBalance` - `equivalentEuroLocalBalance` must be less than or equal to `equivalentEuroTotalBalance` - Only one submission per day per currency - USDC and EURC require separate submissions ## OpenAPI ````yaml openapi/reserve-management.yaml post /v2/reserveManagement/dailyCustodyBalances openapi: 3.0.2 info: version: ${version} title: Reserve Management API description: > The Reserve Management API allows you to report your daily USDC and EURC balances to Circle to comply with regulatory requirements. servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Reserve Management description: Report daily stablecoin balances to Circle. paths: /v2/reserveManagement/dailyCustodyBalances: post: tags: - Reserve Management summary: Create daily custody balance report description: > Creates a daily custody balance report for USDC and EURC and sends it to Circle. For `reportType=eea`, this endpoint represents the four reportable cells of EBA Template S 08.00 for one token and one reference date: CASP total token count and EUR value, plus the EU-client subset token count and EUR value. MiCA / EBA S 08.00 mapping (`reportType=eea`): - S 08.00 Row 0010 / Col 0010 maps to `additionalFields.totalBalance` - S 08.00 Row 0010 / Col 0020 maps to `additionalFields.equivalentEuroTotalBalance` - S 08.00 Row 0020 / Col 0010 maps to `localBalance` - S 08.00 Row 0020 / Col 0020 maps to `additionalFields.equivalentEuroLocalBalance` `localBalance` and `totalBalance` are token-unit counts. `equivalentEuroLocalBalance` and `equivalentEuroTotalBalance` are EUR values. EU clients are determined by habitual residence for natural persons and registered office for legal persons. USD/EUR FX conversion should be based on the ECB rate applicable for that date, as available on the ECB website. Validation rules: - `localBalance` must be less than or equal to `additionalFields.totalBalance` - `equivalentEuroLocalBalance` must be less than or equal to `equivalentEuroTotalBalance` - Only one submission per day per currency - USDC and EURC require separate submissions operationId: ReportDailyCustodyBalances requestBody: content: application/json: schema: $ref: '#/components/schemas/DailyCustodyBalancesRequest' responses: '200': description: > Request with duplicate values and idempotency key has already been made. Existing record is returned. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: title: DuplicateRequest type: object properties: data: $ref: '#/components/schemas/DailyCustodyBalancesResponse' examples: response: value: data: idempotencyKey: ba943ff1-ca16-49b2-ba55-1057e70ca5c7 id: b8627ae8-732b-4d25-b947-1df8f4007a29 createDate: '2025-07-15T18:03:52.429Z' localBalance: 1000000 currency: USDC asOfDate: '2025-06-26' reportType: eea additionalFields: equivalentEuroLocalBalance: 26994.6 totalBalance: 5000000 equivalentEuroTotalBalance: 853949.09 '201': description: | Successfully created daily custody balance report. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: title: NewReportSuccess type: object properties: data: $ref: '#/components/schemas/DailyCustodyBalancesResponse' examples: response: value: data: idempotencyKey: ba943ff1-ca16-49b2-ba55-1057e70ca5c7 id: b8627ae8-732b-4d25-b947-1df8f4007a29 createDate: '2025-07-15T18:03:52.429Z' localBalance: 1000000 currency: USDC asOfDate: '2025-06-26' reportType: eea additionalFields: equivalentEuroLocalBalance: 26994.6 totalBalance: 5000000 equivalentEuroTotalBalance: 853949.09 '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '403': $ref: '#/components/responses/Forbidden' '409': $ref: '#/components/responses/Conflict' security: - bearerAuth: [] components: schemas: DailyCustodyBalancesRequest: type: object required: - idempotencyKey - currency - localBalance - asOfDate - reportType - additionalFields properties: idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' currency: type: string description: The type of token being reported. enum: - USDC - EURC example: USDC localBalance: type: number format: double description: > Regional specific balance for the provided token type, expressed in token units. For `eea`, this is the EU-client subset (not the CASP's total holdings). EU clients are determined by habitual residence for natural persons and registered office for legal persons. For `japan_trust`, this is the total amount held in custody on behalf of customers of the EPIESP. example: 1000000 asOfDate: type: string format: date description: The day being reported in the format YYYY-MM-DD with timezone UTC. example: '2025-06-26' reportType: type: string description: The type of report being created. enum: - eea - japan_trust example: eea additionalFields: type: object description: > Additional fields are required only for the `eea` report type. They are ignored for the `japan_trust` report type. required: - equivalentEuroLocalBalance - totalBalance - equivalentEuroTotalBalance properties: equivalentEuroLocalBalance: type: number format: double description: EUR equivalent of the `localBalance` field. example: 26994.6 totalBalance: type: number format: double description: Tokens held by the EU licensed crypto-asset service provider example: 5000000 equivalentEuroTotalBalance: type: number format: double description: >- EUR equivalent of the reporting CASP's total holdings for the token in scope. example: 853949.09 DailyCustodyBalancesResponse: type: object properties: idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' id: $ref: '#/components/schemas/Id' createDate: type: string format: date-time example: '2025-07-15T18:03:52.429Z' localBalance: type: number format: double description: > Regional specific balance for the provided token type, expressed in token units. For `eea`, this is the EU-client subset (not the CASP's total holdings). EU clients are determined by habitual residence for natural persons and registered office for legal persons. For `japan_trust`, this is the total amount held in custody on behalf of customers of the EPIESP. example: 1000000 currency: type: string description: The type of token being reported. enum: - USDC - EURC example: USDC asOfDate: type: string format: date description: The day being reported in the format YYYY-MM-DD with timezone UTC. example: '2025-06-26' reportType: type: string description: The type of report being created. enum: - eea - japan_trust example: eea additionalFields: type: object description: > Additional fields are required only for the `eea` report type. They are ignored for the `japan_trust` report type. properties: equivalentEuroLocalBalance: type: number format: double description: EUR equivalent of the `localBalance` field. example: 26994.6 totalBalance: type: number format: double description: Tokens held by the EU licensed crypto-asset service provider example: 5000000 equivalentEuroTotalBalance: type: number format: double description: >- EUR equivalent of the reporting CASP's total holdings for the token in scope. example: 853949.09 IdempotencyKey: type: string description: >- Universally unique identifier (UUID v4) idempotency key. This key is utilized to ensure exactly-once execution of mutating requests. format: uuid example: ba943ff1-ca16-49b2-ba55-1057e70ca5c7 Id: type: string description: Unique system generated identifier for the entity. format: uuid example: b8627ae8-732b-4d25-b947-1df8f4007a29 headers: XRequestId: description: >- Universally unique identifier (UUID v4) for the request. Helpful for identifying a request when communicating with Circle support. schema: type: string format: uuid example: 2adba88e-9d63-44bc-b975-9b6ae3440dde responses: BadRequest: description: The request cannot be processed due to a client error. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: BadRequest required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 400 message: Bad request. examples: response: value: code: 400 message: Bad request. NotAuthorized: description: >- The request has not been applied because it lacks valid authentication credentials. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: NotAuthorized required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 401 message: Malformed authorization. examples: response: value: code: 401 message: Malformed authorization. Forbidden: description: >- The request provides authentication, but the authenticated user does not possess sufficient permissions for accessing this resource. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: Forbidden required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 3 message: Forbidden examples: response: value: code: 3 message: Forbidden Conflict: description: >- The request has not been applied because it comes in conflict with another request (such as re-using an idempotencyKey for a different request). headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: Conflict required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 409 message: Conflicts with another request. examples: response: value: code: 409 message: Conflicts with another request. securitySchemes: bearerAuth: type: http scheme: bearer ````