--- title: "CreateMerchantCustomAttributeDefinition" method: POST path: "/v2/merchants/custom-attribute-definitions" tags: ["MerchantCustomAttributes"] --- # CreateMerchantCustomAttributeDefinition `POST /v2/merchants/custom-attribute-definitions` Creates a merchant-related [custom attribute definition](entity:CustomAttributeDefinition) for a Square seller account. Use this endpoint to define a custom attribute that can be associated with a merchant connecting to your application. A custom attribute definition specifies the `key`, `visibility`, `schema`, and other properties for a custom attribute. After the definition is created, you can call [UpsertMerchantCustomAttribute](api-endpoint:MerchantCustomAttributes-UpsertMerchantCustomAttribute) or [BulkUpsertMerchantCustomAttributes](api-endpoint:MerchantCustomAttributes-BulkUpsertMerchantCustomAttributes) to set the custom attribute for a merchant. ## Request body - CreateMerchantCustomAttributeDefinitionRequest — Represents a [CreateMerchantCustomAttributeDefinition](api-endpoint:MerchantCustomAttributes-CreateMerchantCustomAttributeDefinition) request. - `custom_attribute_definition` CustomAttributeDefinition, required — Represents a definition for custom attribute values. A custom attribute definition specifies the key, visibility, schema, and other properties for a custom attribute. - `key` string, nullable — The identifier of the custom attribute definition and its corresponding custom attributes. This value can be a simple key, which is the key that is provided when the custom attribute definition is created, or a qualified key, if the requesting application is not the definition owner. The qualified key consists of the application ID of the custom attribute definition owner followed by the simple key that was provided when the definition was created. It has the format application_id:simple key. The value for a simple key can contain up to 60 alphanumeric characters, periods (.), underscores (_), and hyphens (-). This field can not be changed after the custom attribute definition is created. This field is required when creating a definition and must be unique per application, seller, and resource type. - `schema` object, nullable — The JSON schema for the custom attribute definition, which determines the data type of the corresponding custom attributes. For more information, see [Custom Attributes Overview](https://developer.squareup.com/docs/devtools/customattributes/overview). This field is required when creating a definition. - `name` string, nullable — The name of the custom attribute definition for API and seller-facing UI purposes. The name must be unique within the seller and application pair. This field is required if the `visibility` field is `VISIBILITY_READ_ONLY` or `VISIBILITY_READ_WRITE_VALUES`. - `description` string, nullable — Seller-oriented description of the custom attribute definition, including any constraints that the seller should observe. May be displayed as a tooltip in Square UIs. This field is required if the `visibility` field is `VISIBILITY_READ_ONLY` or `VISIBILITY_READ_WRITE_VALUES`. - `visibility` 'VISIBILITY_HIDDEN' | 'VISIBILITY_READ_ONLY' | 'VISIBILITY_READ_WRITE_VALUES' — The level of permission that a seller or other applications requires to view this custom attribute definition. The `Visibility` field controls who can read and write the custom attribute values and custom attribute definition. - `version` integer — Read only. The current version of the custom attribute definition. The value is incremented each time the custom attribute definition is updated. When updating a custom attribute definition, you can provide this field and specify the current version of the custom attribute definition to enable [optimistic concurrency](https://developer.squareup.com/docs/build-basics/common-api-patterns/optimistic-concurrency). On writes, this field must be set to the latest version. Stale writes are rejected. This field can also be used to enforce strong consistency for reads. For more information about strong consistency for reads, see [Custom Attributes Overview](https://developer.squareup.com/docs/devtools/customattributes/overview). - `updated_at` string — The timestamp that indicates when the custom attribute definition was created or most recently updated, in RFC 3339 format. - `created_at` string — The timestamp that indicates when the custom attribute definition was created, in RFC 3339 format. - `idempotency_key` string — A unique identifier for this request, used to ensure idempotency. For more information, see [Idempotency](https://developer.squareup.com/docs/build-basics/common-api-patterns/idempotency). ## Response `200` Success - CreateMerchantCustomAttributeDefinitionResponse — Represents a [CreateMerchantCustomAttributeDefinition](api-endpoint:MerchantCustomAttributes-CreateMerchantCustomAttributeDefinition) response. Either `custom_attribute_definition` or `errors` is present in the response. - `custom_attribute_definition` CustomAttributeDefinition — Represents a definition for custom attribute values. A custom attribute definition specifies the key, visibility, schema, and other properties for a custom attribute. - `key` string, nullable — The identifier of the custom attribute definition and its corresponding custom attributes. This value can be a simple key, which is the key that is provided when the custom attribute definition is created, or a qualified key, if the requesting application is not the definition owner. The qualified key consists of the application ID of the custom attribute definition owner followed by the simple key that was provided when the definition was created. It has the format application_id:simple key. The value for a simple key can contain up to 60 alphanumeric characters, periods (.), underscores (_), and hyphens (-). This field can not be changed after the custom attribute definition is created. This field is required when creating a definition and must be unique per application, seller, and resource type. - `schema` object, nullable — The JSON schema for the custom attribute definition, which determines the data type of the corresponding custom attributes. For more information, see [Custom Attributes Overview](https://developer.squareup.com/docs/devtools/customattributes/overview). This field is required when creating a definition. - `name` string, nullable — The name of the custom attribute definition for API and seller-facing UI purposes. The name must be unique within the seller and application pair. This field is required if the `visibility` field is `VISIBILITY_READ_ONLY` or `VISIBILITY_READ_WRITE_VALUES`. - `description` string, nullable — Seller-oriented description of the custom attribute definition, including any constraints that the seller should observe. May be displayed as a tooltip in Square UIs. This field is required if the `visibility` field is `VISIBILITY_READ_ONLY` or `VISIBILITY_READ_WRITE_VALUES`. - `visibility` 'VISIBILITY_HIDDEN' | 'VISIBILITY_READ_ONLY' | 'VISIBILITY_READ_WRITE_VALUES' — The level of permission that a seller or other applications requires to view this custom attribute definition. The `Visibility` field controls who can read and write the custom attribute values and custom attribute definition. - `version` integer — Read only. The current version of the custom attribute definition. The value is incremented each time the custom attribute definition is updated. When updating a custom attribute definition, you can provide this field and specify the current version of the custom attribute definition to enable [optimistic concurrency](https://developer.squareup.com/docs/build-basics/common-api-patterns/optimistic-concurrency). On writes, this field must be set to the latest version. Stale writes are rejected. This field can also be used to enforce strong consistency for reads. For more information about strong consistency for reads, see [Custom Attributes Overview](https://developer.squareup.com/docs/devtools/customattributes/overview). - `updated_at` string — The timestamp that indicates when the custom attribute definition was created or most recently updated, in RFC 3339 format. - `created_at` string — The timestamp that indicates when the custom attribute definition was created, in RFC 3339 format. - `errors` Error[] — Any errors that occurred during the request. - `category` 'API_ERROR' | 'AUTHENTICATION_ERROR' | 'INVALID_REQUEST_ERROR' | 'RATE_LIMIT_ERROR' | 'PAYMENT_METHOD_ERROR' | 'REFUND_ERROR' | 'MERCHANT_SUBSCRIPTION_ERROR' | 'EXTERNAL_VENDOR_ERROR', required — Indicates which high-level category of error has occurred during a request to the Connect API. - `code` 'INTERNAL_SERVER_ERROR' | 'UNAUTHORIZED' | 'ACCESS_TOKEN_EXPIRED' | 'ACCESS_TOKEN_REVOKED' | 'CLIENT_DISABLED' | 'FORBIDDEN' | 'INSUFFICIENT_SCOPES' | 'APPLICATION_DISABLED' | 'V1_APPLICATION' | 'V1_ACCESS_TOKEN' | 'CARD_PROCESSING_NOT_ENABLED' | 'MERCHANT_SUBSCRIPTION_NOT_FOUND' | 'BAD_REQUEST' | 'MISSING_REQUIRED_PARAMETER' | 'INCORRECT_TYPE' | 'INVALID_TIME' | 'INVALID_TIME_RANGE' | 'INVALID_VALUE' | 'INVALID_CURSOR' | 'UNKNOWN_QUERY_PARAMETER' | 'CONFLICTING_PARAMETERS' | 'EXPECTED_JSON_BODY' | 'INVALID_SORT_ORDER' | 'VALUE_REGEX_MISMATCH' | 'VALUE_TOO_SHORT' | 'VALUE_TOO_LONG' | 'VALUE_TOO_LOW' | 'VALUE_TOO_HIGH' | 'VALUE_EMPTY' | 'ARRAY_LENGTH_TOO_LONG' | 'ARRAY_LENGTH_TOO_SHORT' | 'ARRAY_EMPTY' | 'EXPECTED_BOOLEAN' | 'EXPECTED_INTEGER' | 'EXPECTED_FLOAT' | 'EXPECTED_STRING' | 'EXPECTED_OBJECT' | 'EXPECTED_ARRAY' | 'EXPECTED_MAP' | 'EXPECTED_BASE64_ENCODED_BYTE_ARRAY' | 'INVALID_ARRAY_VALUE' | 'INVALID_ENUM_VALUE' | 'INVALID_CONTENT_TYPE' | 'INVALID_FORM_VALUE' | 'CUSTOMER_NOT_FOUND' | 'ONE_INSTRUMENT_EXPECTED' | 'NO_FIELDS_SET' | 'TOO_MANY_MAP_ENTRIES' | 'MAP_KEY_LENGTH_TOO_SHORT' | 'MAP_KEY_LENGTH_TOO_LONG' | 'CUSTOMER_MISSING_NAME' | 'CUSTOMER_MISSING_EMAIL' | 'INVALID_PAUSE_LENGTH' | 'INVALID_DATE' | 'UNSUPPORTED_COUNTRY' | 'UNSUPPORTED_CURRENCY' | 'APPLE_TTP_PIN_TOKEN' | 'CARD_EXPIRED' | 'INVALID_EXPIRATION' | 'INVALID_EXPIRATION_YEAR' | 'INVALID_EXPIRATION_DATE' | 'UNSUPPORTED_CARD_BRAND' | 'UNSUPPORTED_ENTRY_METHOD' | 'INVALID_ENCRYPTED_CARD' | 'INVALID_CARD' | 'PAYMENT_AMOUNT_MISMATCH' | 'GENERIC_DECLINE' | 'CVV_FAILURE' | 'ADDRESS_VERIFICATION_FAILURE' | 'INVALID_ACCOUNT' | 'CURRENCY_MISMATCH' | 'INSUFFICIENT_FUNDS' | 'INSUFFICIENT_PERMISSIONS' | 'CARDHOLDER_INSUFFICIENT_PERMISSIONS' | 'INVALID_LOCATION' | 'TRANSACTION_LIMIT' | 'VOICE_FAILURE' | 'PAN_FAILURE' | 'EXPIRATION_FAILURE' | 'CARD_NOT_SUPPORTED' | 'READER_DECLINED' | 'INVALID_PIN' | 'MISSING_PIN' | 'MISSING_ACCOUNT_TYPE' | 'INVALID_POSTAL_CODE' | 'INVALID_FEES' | 'MANUALLY_ENTERED_PAYMENT_NOT_SUPPORTED' | 'PAYMENT_LIMIT_EXCEEDED' | 'GIFT_CARD_AVAILABLE_AMOUNT' | 'ACCOUNT_UNUSABLE' | 'BUYER_REFUSED_PAYMENT' | 'DELAYED_TRANSACTION_EXPIRED' | 'DELAYED_TRANSACTION_CANCELED' | 'DELAYED_TRANSACTION_CAPTURED' | 'DELAYED_TRANSACTION_FAILED' | 'CARD_TOKEN_EXPIRED' | 'CARD_TOKEN_USED' | 'AMOUNT_TOO_HIGH' | 'UNSUPPORTED_INSTRUMENT_TYPE' | 'REFUND_AMOUNT_INVALID' | 'REFUND_ALREADY_PENDING' | 'PAYMENT_NOT_REFUNDABLE' | 'PAYMENT_NOT_REFUNDABLE_DUE_TO_DISPUTE' | 'REFUND_ERROR_PAYMENT_NEEDS_COMPLETION' | 'REFUND_DECLINED' | 'INSUFFICIENT_PERMISSIONS_FOR_REFUND' | 'INVALID_CARD_DATA' | 'SOURCE_USED' | 'SOURCE_EXPIRED' | 'UNSUPPORTED_LOYALTY_REWARD_TIER' | 'LOCATION_MISMATCH' | 'ORDER_UNPAID_NOT_RETURNABLE' | 'PARTIAL_PAYMENT_DELAY_CAPTURE_NOT_SUPPORTED' | 'IDEMPOTENCY_KEY_REUSED' | 'UNEXPECTED_VALUE' | 'SANDBOX_NOT_SUPPORTED' | 'INVALID_EMAIL_ADDRESS' | 'INVALID_PHONE_NUMBER' | 'CHECKOUT_EXPIRED' | 'BAD_CERTIFICATE' | 'INVALID_SQUARE_VERSION_FORMAT' | 'API_VERSION_INCOMPATIBLE' | 'CARD_PRESENCE_REQUIRED' | 'UNSUPPORTED_SOURCE_TYPE' | 'CARD_MISMATCH' | 'PLAID_ERROR' | 'PLAID_ERROR_ITEM_LOGIN_REQUIRED' | 'PLAID_ERROR_RATE_LIMIT' | 'PAYMENT_SOURCE_NOT_ENABLED_FOR_TARGET' | 'CARD_DECLINED' | 'VERIFY_CVV_FAILURE' | 'VERIFY_AVS_FAILURE' | 'CARD_DECLINED_CALL_ISSUER' | 'CARD_DECLINED_VERIFICATION_REQUIRED' | 'BAD_EXPIRATION' | 'CHIP_INSERTION_REQUIRED' | 'ALLOWABLE_PIN_TRIES_EXCEEDED' | 'RESERVATION_DECLINED' | 'UNKNOWN_BODY_PARAMETER' | 'NOT_FOUND' | 'APPLE_PAYMENT_PROCESSING_CERTIFICATE_HASH_NOT_FOUND' | 'METHOD_NOT_ALLOWED' | 'NOT_ACCEPTABLE' | 'REQUEST_TIMEOUT' | 'CONFLICT' | 'GONE' | 'REQUEST_ENTITY_TOO_LARGE' | 'UNSUPPORTED_MEDIA_TYPE' | 'UNPROCESSABLE_ENTITY' | 'RATE_LIMITED' | 'NOT_IMPLEMENTED' | 'BAD_GATEWAY' | 'SERVICE_UNAVAILABLE' | 'TEMPORARY_ERROR' | 'GATEWAY_TIMEOUT', required — Indicates the specific error that occurred during a request to a Square API. - `detail` string — A human-readable description of the error for debugging purposes. - `field` string — The name of the field provided in the original request (if any) that the error pertains to. --- [API](https://skmtc.net/square/apis/connect-api.md) · [All operations](https://skmtc.net/square/apis/connect-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/square/connect-api/versions/6a5164284e41/schema)