> ## Documentation Index > Fetch the complete documentation index at: https://docs.interchange.io/llms.txt > Use this file to discover all available pages before exploring further. # Create media billing entity (admin) > Create a media billing entity. An org's FIRST entity always becomes PRIMARY (the mandatory backstop every media-transacting org must have) regardless of `isPrimary`. Admin-only. ## OpenAPI ````yaml /v2/buyer-api-v2.yaml post /billing/media-entities openapi: 3.0.0 info: title: Scope3 Buyer API version: 2.0.0 description: |- REST API for advertisers to manage advertisers, campaigns, and reporting. ## Authentication All endpoints require a Bearer token in the Authorization header: ``` Authorization: Bearer your-api-key ``` ## Base URL `https://api.interchange.io/api/v2/buyer` ## For AI Agents AI agents can use the MCP endpoint at `/mcp/v2/buyer` with three tools: - `initialize`: Start an MCP session - `api_call`: Make REST API calls - `ask_about_capability`: Learn about API features servers: - url: https://api.interchange.io/api/v2/buyer description: Production server security: [] tags: - name: Account description: Account management, service tokens, and preferences - name: Advertisers description: Manage advertisers - name: Product Discovery description: Discover and select products - name: Campaigns description: Manage advertising campaigns - name: Creatives description: Build, manage, and sync campaign creatives via AdCP Creative Protocol - name: Reporting description: Access performance metrics - name: Event Sources description: >- Manage event source configurations and log conversion/marketing events for attribution - name: Property Lists description: Validate property lists against AAO registry - name: Sales Agents description: View and connect sales agents - name: Measurement description: Measurement sources, records, context, and freshness - name: Syndication description: Syndicate resources to ADCP agents - name: Tasks description: Track async operation status - name: Planning Briefs description: >- Share prospective briefs with publishers and collect their fit/quote/clarify/decline/book responses (gated by the demand-supply-signals flag). - name: Buyer Billing description: >- Consolidated invoicing for buyers — invoices and pending invoice items issued by Scope3 across the buyer customer. - name: MCP description: Model Context Protocol endpoints for AI agents paths: /billing/media-entities: servers: - url: https://api.interchange.io/api/v2 description: Production server post: tags: - Media Billing summary: Create media billing entity (admin) description: >- Create a media billing entity. An org's FIRST entity always becomes PRIMARY (the mandatory backstop every media-transacting org must have) regardless of `isPrimary`. Admin-only. operationId: createMediaBillingEntity requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateMediaBillingEntityBody' responses: '200': description: Create media billing entity (admin) content: application/json: schema: $ref: '#/components/schemas/CreateMediaBillingEntityResponse' '400': description: Bad request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: ACCESS_DENIED (not an account admin). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '409': description: CONFLICT (an entity with this name and currency already exists). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - bearerAuth: [] components: schemas: CreateMediaBillingEntityBody: description: >- Create a media billing entity — a legal entity Scope3 invoices for media spend. type: object properties: entityName: description: >- Legal name of the media billing entity (e.g. "WPP South Africa (Pty) Ltd"). type: string minLength: 1 maxLength: 255 countryCode: description: >- Country of the billing entity, as an ISO 3166-1 alpha-2 code. Metadata only — drives tax treatment and bank/address formatting, never invoice routing (money-streams.md §6.4). example: US type: string pattern: ^[A-Z]{2}$ currency: description: ISO 4217 currency code example: USD type: string pattern: ^[A-Z]{3}$ billingEmails: description: >- Invoicing contact email(s) for this entity. At least one is required. minItems: 1 maxItems: 20 type: array items: type: string format: email pattern: >- ^(?!\.)(?!.*\.\.)([A-Za-z0-9_'+\-\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\-]*\.)+[A-Za-z]{2,}$ addressLine1: description: Entity street address, line 1. type: string minLength: 1 maxLength: 255 addressLine2: description: Entity street address, line 2 (optional). type: string maxLength: 255 city: description: Entity city. type: string minLength: 1 maxLength: 128 state: description: Entity state/province/region (optional). type: string maxLength: 128 postalCode: description: Entity postal/ZIP code. type: string minLength: 1 maxLength: 32 taxId: description: >- Tax identifier for this entity (e.g. VAT number, EIN), when applicable. type: string maxLength: 64 isPrimary: description: >- Set true to make this the org's PRIMARY media billing entity (the mandatory backstop every media-transacting org must have), demoting any other primary entity. Omit to leave the current primary/non-primary status unchanged. An org's FIRST entity always becomes primary regardless of this field. type: boolean required: - entityName - countryCode - currency - billingEmails - addressLine1 - city - postalCode CreateMediaBillingEntityResponse: type: object properties: entity: $ref: '#/components/schemas/MediaBillingEntity' required: - entity additionalProperties: false ErrorResponse: description: Standard error response type: object properties: data: type: string nullable: true enum: - null error: $ref: '#/components/schemas/ApiError' required: - data - error additionalProperties: false MediaBillingEntity: description: A media billing entity — a legal entity Scope3 invoices for media spend. type: object properties: id: description: Media billing entity ID type: integer minimum: -9007199254740991 maximum: 9007199254740991 entityName: description: >- Legal name of the media billing entity (e.g. "WPP South Africa (Pty) Ltd"). type: string minLength: 1 maxLength: 255 countryCode: description: >- Country of the billing entity, as an ISO 3166-1 alpha-2 code. Metadata only — drives tax treatment and bank/address formatting, never invoice routing (money-streams.md §6.4). example: US type: string pattern: ^[A-Z]{2}$ currency: description: ISO 4217 currency code example: USD type: string pattern: ^[A-Z]{3}$ billingEmails: description: >- Invoicing contact email(s) for this entity. At least one is required. minItems: 1 maxItems: 20 type: array items: type: string format: email pattern: >- ^(?!\.)(?!.*\.\.)([A-Za-z0-9_'+\-\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\-]*\.)+[A-Za-z]{2,}$ addressLine1: description: Entity street address, line 1. type: string minLength: 1 maxLength: 255 addressLine2: nullable: true description: Entity street address, line 2 (optional). type: string maxLength: 255 city: description: Entity city. type: string minLength: 1 maxLength: 128 state: nullable: true description: Entity state/province/region (optional). type: string maxLength: 128 postalCode: description: Entity postal/ZIP code. type: string minLength: 1 maxLength: 32 taxId: nullable: true description: >- Tax identifier for this entity (e.g. VAT number, EIN), when applicable. type: string maxLength: 64 isPrimary: description: >- Whether this is the org's PRIMARY media billing entity — the mandatory backstop used when no advertiser or account attachment matches. At most one entity per org is primary. type: boolean createdAt: description: Creation timestamp (ISO 8601) type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d+)?)?(?:Z))$ updatedAt: description: Last update timestamp (ISO 8601) type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d+)?)?(?:Z))$ required: - id - entityName - countryCode - currency - billingEmails - addressLine1 - city - postalCode - isPrimary - createdAt - updatedAt additionalProperties: false ApiError: description: Structured error object type: object properties: code: description: Machine-readable error code type: string message: description: Human-readable error message type: string field: description: Field path associated with the error type: string details: description: Additional error context type: object additionalProperties: {} required: - code - message additionalProperties: false securitySchemes: bearerAuth: type: http scheme: bearer description: API key or access token ````