> ## Documentation Index > Fetch the complete documentation index at: https://docs.airscale.io/llms.txt > Use this file to discover all available pages before exploring further. # US DNC Checker > Check whether a US phone number is listed on the US Do Not Call list. Rate limit: 5 requests per second per workspace. Submit a US phone number using `phone`. The operation normalizes accepted numbers to `+1` format and returns whether the number is listed on the US Do Not Call (DNC) list. For UK numbers, use the [UK DNC Checker](https://docs.airscale.io/api-reference/uk-dnc-checker.md). > [!NOTE] > > A successful check costs 1 credit whether `listed` is `true` or `false`. The limit is 5 requests per second per workspace. Validation and lookup failures are not charged. `POST /v1/dnc-check` remains supported for existing integrations; it accepts the same request and returns the same response, pricing, and limits as `POST /v1/us-dnc-check`. Non-US numbers return `422` with `code: "unsupported_phone_region"` without starting a check. Malformed numbers return `422` with `code: "invalid_input"`. Correct the input before retrying either response. `phone_number` and `mobile_phone` are accepted aliases. `phone` takes precedence when non-null, followed by `phone_number`, then `mobile_phone`. Use one field to avoid ambiguity. ## Read a successful result | Field | Meaning | | - | - | | `status` | `success` for a completed check. | | `phone` | Normalized US phone number. | | `listed` | Boolean indicating whether the number is listed. | | `result` | `Listed on DNC` or `Not listed on DNC`. | | `credits_used` | Credits charged for this check. | | `credits_remaining` | Remaining workspace credit balance. | After `429`, retry in a later second with bounded exponential backoff. For temporary `502` or `503` responses, retry with increasing delays and a fixed retry limit; contact support if errors persist. The maximum JSON body size is 256 KiB. ## Next step Review [Authentication](https://docs.airscale.io/api-reference/authentication.md) before updating an existing integration. ## OpenAPI ````yaml openapi.json POST /v1/us-dnc-check openapi: 3.1.0 info: title: Airscale Public API version: '2026-09-11' description: >- Search, enrich, resolve public business data, and monitor job changes with Airscale. x-airscale-source-repository: ViceScale/airscale-code x-airscale-source-sha: 1de19e1b70a052a4b8d9c2075021a7e5e7a94d51 servers: - url: https://api.airscale.io description: Production security: - bearerAuth: [] tags: - name: Search and discovery description: Search people, companies, and the web. - name: Contact data description: Find professional and personal contact data. - name: Profiles and reverse lookup description: Extract profiles or resolve a person from known contact data. - name: Post engagement description: Retrieve and enrich people who liked or commented on LinkedIn posts. - name: LinkedIn content description: >- Search LinkedIn posts, read profile and company feeds, and retrieve profile comments and comment reactions. - name: Job change monitoring description: Track LinkedIn profiles and receive job-change events. - name: New hire monitoring description: Watch companies or the market for people who start a matching role. - name: Post engagement monitoring description: >- Follow LinkedIn company pages and profiles and receive the people who engage with their posts. - name: Account description: Inspect workspace account state. - name: Miscellaneous description: >- Find website technologies and check WhatsApp availability, Meta ads, and email deliverability. paths: /v1/us-dnc-check: post: tags: - Miscellaneous summary: Check a US phone number against the US DNC list description: >- Checks a US phone number against the US Do Not Call list. A successful check costs one credit whether the number is listed or not. Non-US and malformed numbers are rejected before the lookup. The original /v1/dnc-check route accepts the same request and returns the same response for existing integrations. For UK numbers, use /v1/uk-dnc-check. operationId: checkDnc requestBody: required: true content: application/json: schema: type: object properties: phone: type: string minLength: 1 description: >- Recommended phone field. A US phone number, normalized to +1 format. phone_number: type: string description: Alias used only if phone is null or absent. mobile_phone: type: string description: >- Alias used only if phone and phone_number are null or absent. anyOf: - required: - phone - required: - phone_number - required: - mobile_phone examples: example: value: phone: '+12025550147' responses: '200': description: The result of a completed DNC check. content: application/json: schema: type: object required: - status - phone - listed - result - credits_used - credits_remaining properties: status: type: string const: success phone: type: string listed: type: boolean result: type: string enum: - Listed on DNC - Not listed on DNC credits_used: type: number credits_remaining: type: - number - 'null' examples: example: value: status: success phone: '+12025550147' listed: false result: Not listed on DNC credits_used: 1 credits_remaining: 99 '400': description: Invalid request. content: application/json: schema: $ref: '#/components/schemas/Error' '401': $ref: '#/components/responses/Unauthorized' '403': description: Insufficient credits or access. content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Unknown path or method. content: application/json: schema: $ref: '#/components/schemas/Error' '413': description: Request body exceeds 256 KiB. content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: Invalid or unsupported US phone number. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Workspace rate limit exceeded. content: application/json: schema: $ref: '#/components/schemas/Error' '500': description: Service configuration error. content: application/json: schema: $ref: '#/components/schemas/Error' '502': description: Upstream service failed. content: application/json: schema: $ref: '#/components/schemas/Error' '503': description: >- A required service is temporarily unavailable. Retry after the Retry-After delay when one is returned. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: Error: type: object additionalProperties: true properties: error: type: string message: type: string responses: Unauthorized: description: The Bearer token is missing or invalid. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: API key description: >- Use an Airscale workspace API key. Never expose the key in client-side code. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.