> ## 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. # Create a webhook subscription > Create a webhook subscription by configuring an endpoint to receive notifications. ## OpenAPI ````yaml openapi/configurations.yaml post /v2/cpn/notifications/subscriptions openapi: 3.0.3 info: version: '1.0' title: API Overview description: Common endpoints shared across all CPN APIs. license: name: Proprietary url: https://www.circle.com/legal servers: - url: https://api.circle.com security: [] tags: - name: Health description: Inspect the health of the API. - name: Webhook Subscriptions description: Manage subscriptions to notifications. paths: /v2/cpn/notifications/subscriptions: post: tags: - Webhook Subscriptions summary: Create a webhook subscription description: > Create a webhook subscription by configuring an endpoint to receive notifications. operationId: createSubscription parameters: - $ref: '#/components/parameters/XRequestId' requestBody: $ref: '#/components/requestBodies/CreateSubscription' responses: '200': content: application/json: schema: $ref: '#/components/schemas/SubscriptionResponse' description: Successfully created a webhook subscription. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' security: - BearerAuth: [] components: parameters: XRequestId: name: X-Request-Id description: >- Developer-provided parameter used to identify this request. Useful when communicating with Circle Support. in: header schema: $ref: '#/components/schemas/XRequestId' requestBodies: CreateSubscription: content: application/json: schema: description: Required parameters to create a new subscription. type: object required: - endpoint properties: endpoint: type: string description: >- URL of the endpoint to subscribe to notifications. Must be publicly accessible, use HTTPS, and respond with a 2XX status to a POST request. example: https://example.org/handler/for/notifications notificationTypes: type: array description: >- The notification types to subscribe to. If not provided, the webhook will be unrestricted, and a notification is sent for every notification type. If the wildcard (`*`) or any combination of the wildcard and a set of notification types is provided, the webhook will also be unrestricted. If a set of notification types are provided, the webhook will be restricted. The restricted status of the webhook is returned in the response object. Each category of notification types also has a wildcard, which will restrict to all notification types from that category. items: $ref: '#/components/schemas/NotificationType' example: - '*' required: true description: Schema for the request payload to create a new subscription. schemas: SubscriptionResponse: title: SubscriptionResponse type: object properties: data: $ref: '#/components/schemas/Subscription' XRequestId: type: string description: >- A unique identifier, which can be helpful for identifying a request when communicating with Circle support. example: 2adba88e-9d63-44bc-b975-9b6ae3440dde NotificationType: type: string description: > The type of notification that can be subscribed to. Supports wildcard patterns (e.g., 'cpn.payment.*') to subscribe to all notifications within a category. The '*' wildcard can be used to subscribe to all notifications. enum: - '*' - cpn.payment.* - cpn.payment.cryptoFundsPending - cpn.payment.fiatPaymentInitiated - cpn.payment.completed - cpn.payment.failed - cpn.payment.delayed - cpn.rfi.* - cpn.rfi.informationRequired - cpn.rfi.inReview - cpn.rfi.approved - cpn.rfi.rejected - cpn.transaction.* - cpn.transaction.broadcasted - cpn.transaction.completed - cpn.transaction.failed example: cpn.payment.completed Subscription: type: object title: Subscription description: Contains information about a webhook notification subscription. required: - id - name - endpoint - enabled - createDate - updateDate properties: id: $ref: '#/components/schemas/Id' name: type: string description: Name of the webhook notification subscription. example: Transactions Webhook endpoint: type: string description: >- URL of the endpoint subscribing to notifications. Must be enabled to receive notifications. example: https://example.org/handler/for/notifications enabled: type: boolean description: >- Whether the subscription is enabled. `true` indicates the subscription is enabled. example: true createDate: $ref: '#/components/schemas/CreateDate' updateDate: $ref: '#/components/schemas/UpdateDate' notificationTypes: type: array description: The notification types on which a notification will be sent. items: $ref: '#/components/schemas/NotificationType' example: - '*' restricted: type: boolean description: >- Whether the webhook is restricted to specific notification types. An unrestricted webhook will notify on all notification types. A restricted webhook will only notify on the notification types in the `notificationTypes` field. example: false ErrorCode: title: ErrorCode type: integer description: Code that corresponds to the error. enum: - -1 - 0 - 1 - 2 - 3 - 290000 - 290001 - 290100 - 290101 - 290102 - 290103 - 290200 - 290201 - 290202 - 290203 - 290204 - 290205 - 290206 - 290211 - 290300 - 290301 - 290302 - 290303 - 290304 - 290305 - 290306 - 290307 - 290308 - 290309 - 290310 - 290311 - 290312 - 290313 - 290314 - 290315 - 290316 - 290317 - 290318 - 290319 - 290320 - 290321 - 290322 - 290323 - 290324 - 290325 - 290327 - 290328 - 290329 - 290330 - 290331 - 290332 - 290333 - 290338 - 290339 - 290340 - 290341 - 290349 - 290352 - 290400 - 290401 - 290500 - 290502 - 290503 - 290600 - 290601 - 290602 - 290603 - 290604 - 290605 - 290606 x-enum-descriptions: - Unknown error - Success - API parameter missing - API parameter invalid - Forbidden - >- Parameters of request do not match the tenancy environment associated with request - A request with this idempotency key has already been processed. - Amount provided is outside our supported limits - No bfis available to create requested quote - Parameters of request do not match any supported payment routes - Route does not support the requested use case - Quote not found with provided id - Quote already used by another payment - Quote past timestamp at which it expires - Blockchain for sender address does not blockchain requested in quote - Provided wallet address is on sanctioned lists - Pending RFI verification - RFI rejected - Payment use case does not match the quote. - Payment already has an associated active or completed transaction - Blockchain is not supported by CPN - Blockchain is not supported for V2 transactions - Submitting a transaction not in submittable status - Payment not in correct status for processing a onchain transfer - The payment is not found - The transaction is not found - A signed transaction for the transaction has already been submitted - The payment is expired - >- The signed transaction is expired. Solana has a concept of recent blockhash in a transaction that expires after 150 blocks (~1 min) - >- The nonce in the signed transaction is lower than the current wallet nonce - The signed transaction payload does not match the payment - The sender's wallet balance is insufficient - The fee payer wallet lacks enough gas - >- The CPN Payment ID provided in the signed data (e.g., in the Solana memo or EIP-712 structure) does not match the expected value - >- The gas price in the signed transaction is below network thresholds. The fee must exceed the estimated high fee to ensure prompt confirmation - >- When resubmitting (e.g., for acceleration), the wallet address to sign the raw transaction or nonce does not match the original submission - >- The full node used by CPN is currently unavailable or returns an unexpected error during transaction validation - The Payment Ref ID has already been used on-chain - >- For EVM chains, the gas limit in the signed transaction is insufficient to cover the execution costs. For Solana, the allocated compute budget falls short of the transaction's requirements, preventing successful execution - >- The nonce has already been used with the same sender in another signed transaction submission for a CPN payment. The OFI must use a unique nonce - The signature in the transaction is invalid - Provided wallet address is on sanctioned lists - The blockchain is not supported by CPN - The cross-chain is not supported by CPN yet - Completed transaction exist. No need to accelerate - The signed transaction cannot be decoded or is invalid - The Solana account specified for transaction is not found - The targetted transaction for action is expired - >- Please sign existing transaction or wait for signed transaction to be broadcast - No broadcasted transaction to be accelerated - The Solana account specified for transaction is invalid - >- Another transaction for the same CPN payment has already been submitted and is being broadcasted - >- A signature for the transaction has already been submitted and accepted. - >- The submitted signature cannot be verified against the typed data to be signed. This typically indicates that the signature signed with the wrong private key, or the typed data gets manipulated before signing. - >- The ERC-20 allowance granted to the Permit2 contract is insufficient to cover the total required token amount for the payment, including both the payment amount and associated fees. - >- The Permit2 nonce included in the typed data for the sender has already been used. - >- Blockchain is not supported for V1 transactions; use transactionVersion=VERSION_2. - >- The signed transaction was submitted after the onchain settlement cutoff. - RFI is past timestamp at which it expires - RFI cannot be submitted in current status - >- The decryption process failed, possibly due to an invalid key or corrupted data - >- The JWE compact payload is not formatted correctly or is missing required components - >- The JWE compact payload was not encrypted with a supported encryption algorithm - Ticket reference ID is required for escalation tickets - Original ticket not found with provided reference ID - Issue type is not allowed for this origin - Payment not found with provided ID - Failed to create Circle Salesforce support ticket - Failed to create a BFI support ticket - Support ticket not found with provided ID DescriptiveError: title: DescriptiveError type: object required: - error - message properties: error: $ref: '#/components/schemas/DescriptiveErrorType' location: type: string nullable: true description: The key or path where the error occurred message: type: string description: Detailed description of the error Id: type: string format: uuid description: System-generated unique identifier of the resource. example: c4d1da72-111e-4d52-bdbf-2e74a2d803d5 CreateDate: type: string format: date-time description: Date and time when the resource was created example: '2023-01-01T12:04:05Z' UpdateDate: type: string format: date-time description: Date and time when the resource was last updated example: '2023-01-01T12:04:05Z' DescriptiveErrorType: title: DescriptiveErrorType type: string enum: - MISSING_OR_INVALID_FIELD description: Type of descriptive error headers: XRequestId: description: > Circle-generated universally unique identifier (UUID v4). Useful for identifying a specific request when communicating with Circle Support. schema: $ref: '#/components/schemas/XRequestId' responses: BadRequest: content: application/json: schema: type: object title: BadRequestResponse required: - code - message properties: code: $ref: '#/components/schemas/ErrorCode' message: type: string description: Human-readable message that describes the error. example: Unknown error occurred errors: type: array description: Array of detailed error descriptions items: $ref: '#/components/schemas/DescriptiveError' example: code: 400 message: Bad request. description: Request cannot be processed due to a client error. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' NotAuthorized: content: application/json: schema: type: object title: NotAuthorizedResponse required: - code - message properties: code: $ref: '#/components/schemas/ErrorCode' message: type: string description: Human-readable message that describes the error. example: Unknown error occurred errors: type: array description: Array of detailed error descriptions items: $ref: '#/components/schemas/DescriptiveError' example: code: 401 message: Malformed authorization. description: >- Request has not been applied because it lacks valid authentication credentials. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: PREFIX:ID:SECRET description: >- Circle's API Keys are formatted in the following structure "PREFIX:ID:SECRET". All three parts are requred to make a successful request. ````