> ## Documentation Index > Fetch the complete documentation index at: https://docs.knotapi.com/llms.txt > Use this file to discover all available pages before exploring further. # Create Knot Zero Link > Create a Knot Zero link for a single user. ## OpenAPI ````yaml POST /zero-link/create openapi: 3.1.0 info: title: Knot API description: An API to interact with the Knot merchant connectivity platform. version: 1.0.0 servers: - url: https://development.knotapi.com description: Development server security: - basicAuth: [] paths: /zero-link/create: post: summary: Create Knot Zero Link description: Create a Knot Zero link for a single user. operationId: clip_link_create requestBody: description: The parameters to include in the user's link. content: application/json: schema: type: object properties: type: type: string enum: - card_switcher description: Product to associate the link with. example: card_switcher phone_number: type: string description: >- User's phone number in E.164 format. Must be a valid US or Canadian phone number. Knot sends a one-time code to this number to verify the user each time they open the link. example: '+12025550123' external_user_id: type: string description: Your unique identifier for the user. example: 123abc maxLength: 256 card_id: type: string description: Your unique identifier for the user's card. example: 81n9al10a0ayn13 maxLength: 256 required: - type - phone_number - external_user_id - card_id examples: CreateLink: summary: Create link value: type: card_switcher phone_number: '+12025550123' external_user_id: 123abc card_id: 81n9al10a0ayn13 responses: '200': description: Successful request. content: application/json: schema: type: object properties: link: type: string description: >- The Knot Zero link for the user: your base link with a unique token appended that references the user's stored parameters. Share it as a URL or encode it as a QR code. The link can be opened any number of times, with a new one-time code each time, and expires after 1 year. It stops working earlier if you create a new link for the same user and card, or revoke it. example: >- https://clip.knotapi.com/switch?token=example_knot_zero_token_1xxxxxxxxxxxxxxxxxx token: type: string description: >- The unique token in `link`, returned separately so you don't need to parse it from the link. example: example_knot_zero_token_1xxxxxxxxxxxxxxxxxx '400': description: Bad request. content: application/json: schema: $ref: '#/components/schemas/Error' examples: TypeRequired: summary: type is missing value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: The type field is required. PhoneNumberRequired: summary: phone_number is missing value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: The phone number field is required. InvalidPhoneNumber: summary: Phone number is invalid value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: The phone number format is invalid. UnsupportedPhoneNumber: summary: Phone number isn't a valid US or Canadian number value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: >- The phone number must be a valid number in a supported country. ExternalUserIdRequired: summary: external_user_id is missing value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: The external user id field is required. CardIdRequired: summary: card_id is missing value: error_type: INVALID_REQUEST error_code: INVALID_FIELD error_message: The card id field is required. '401': description: Unauthorized request. content: application/json: schema: $ref: '#/components/schemas/Error' examples: AuthFailed: summary: Auth failed value: error_type: INVALID_INPUT error_code: INVALID_API_KEYS error_message: Invalid client_id or secret provided. '403': description: Forbidden request. content: application/json: schema: $ref: '#/components/schemas/Error' examples: NoAccess: summary: No access value: error_type: INVALID_REQUEST error_code: NO_ACCESS error_message: >- Knot Zero is not enabled. Please contact Knot for access to this endpoint. '429': description: Too many requests. Limited to 600 requests per minute per client. content: application/json: schema: $ref: '#/components/schemas/Error' examples: RateLimited: summary: Rate limited value: error_type: RATE_LIMIT_ERROR error_code: TOO_MANY_REQUESTS error_message: >- Rate limit exceeded. Please retry after the time indicated in the Retry-After header. retry_after: 42 components: schemas: Error: type: object properties: error_type: type: string description: Type of error. enum: - INVALID_INPUT - INVALID_REQUEST - USER_ERROR - SESSION_ERROR - MERCHANT_ACCOUNT_ERROR - MERCHANT_ERROR - SUBSCRIPTION_ERROR - TRANSACTION_ERROR - CART_ERROR - WEBHOOK_ENDPOINT_ERROR example: INVALID_REQUEST error_code: type: string description: Error code. enum: - INVALID_API_KEYS - INVALID_FIELD - INVALID_JWE - INVALID_CURSOR_FORMAT - USER_NOT_FOUND - MERCHANT_ACCOUNT_NOT_FOUND - MERCHANT_ACCOUNT_DISCONNECTED - SESSION_NOT_FOUND - EXTEND_NOT_SUPPORTED - MERCHANT_UNAVAILABLE - NO_ACCESS - TRANSACTION_NOT_FOUND - NO_TRANSACTIONS - SUBSCRIPTION_NOT_FOUND - CANCELLABLE_SUBSCRIPTION_NOT_FOUND - MULTIPLE_CANCELLABLE_SUBSCRIPTIONS_FOUND - ONGOING_OPERATION - CART_NOT_FOUND - FULFILLMENT_NOT_FOUND - INVALID_ACCESS_TOKEN - INSUFFICIENT_SCOPE - INSUFFICIENT_ROLE - WEBHOOK_ENDPOINT_NOT_FOUND - WEBHOOK_ENDPOINT_LIMIT_REACHED - WEBHOOK_ENDPOINT_ALREADY_EXISTS - RATE_LIMIT_EXCEEDED - ENVIRONMENT_MISMATCH example: INVALID_FIELD error_message: type: string description: Detailed error message. example: The limit may not be greater than 10. securitySchemes: basicAuth: type: http scheme: basic description: >- Basic authentication header of the form `Basic `, where `` is the base64-encoded string `username:password`. Use your `client_id` as the `username` and your `secret` as the `password` value. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.