> ## Documentation Index > Fetch the complete documentation index at: https://blackbox.dasha.ai/llms.txt > Use this file to discover all available pages before exploring further. # Add custom SIP domain > Registers a hostname you control as a SIP domain for registered inbound calls. The domain starts in PendingVerification. Publish the DNS records from the response, then call verify. Once Active, pass its id as sipDomainId when registering a call to receive sip:{callId}@{your-domain}. ## DNS records The response contains two kinds of records: * **Verification** — a `TXT` record at `_dasha-verify.{domain}` proving you control the hostname. Required before the domain can be verified. * **Routing** — a `CNAME` from the domain to the Dasha SIP host, so that calls placed to `sip:{callId}@{domain}` reach Dasha. SIP phones and PBXs resolve the host with A records, which the CNAME provides. Use a dedicated hostname: a CNAME cannot share its name with other records. DNS changes can take a few minutes to propagate. Call the verify endpoint once the TXT record is visible. ## OpenAPI ````yaml https://blackbox.dasha.ai/swagger/v1/swagger.json post /api/v1/sip-domains openapi: 3.0.4 info: title: Dasha BlackBox Agent API description: API for managing AI agents and calls contact: name: DashaAI Team email: support@dasha.ai version: v1 servers: - url: https://blackbox.dasha.ai description: Dasha BlackBox Agent API security: - ApiKey: [] - OAuth: [] tags: - name: ActivityLogs - name: Agents - name: AgentTestCases - name: CallResults - name: Calls - name: Chats - name: Copilot - name: CustomerData - name: Mcp - name: Media - name: Misc - name: PronunciationDictionaries - name: Providers - name: SipAliases - name: SipCredentials - name: SipDomains - name: SipPhoneNumbers - name: SipRegisterCallWebhook - name: TextChat - name: TwilioProvider - name: Voice - name: WebhookTest - name: WebIntegrations - name: WebSocket description: WebSocket endpoints for real-time communication paths: /api/v1/sip-domains: post: tags: - SipDomains summary: Add custom SIP domain description: >- Registers a hostname you control as a SIP domain for registered inbound calls. The domain starts in PendingVerification. Publish the DNS records from the response, then call verify. Once Active, pass its id as sipDomainId when registering a call to receive sip:{callId}@{your-domain}. requestBody: description: Domain to add content: application/json: schema: allOf: - $ref: '#/components/schemas/SipDomainRequestDto' description: >- Request to add a custom SIP domain for registered inbound calls. The domain must be a hostname you control; you prove ownership with a DNS TXT record before it becomes usable. text/json: schema: allOf: - $ref: '#/components/schemas/SipDomainRequestDto' description: >- Request to add a custom SIP domain for registered inbound calls. The domain must be a hostname you control; you prove ownership with a DNS TXT record before it becomes usable. application/*+json: schema: allOf: - $ref: '#/components/schemas/SipDomainRequestDto' description: >- Request to add a custom SIP domain for registered inbound calls. The domain must be a hostname you control; you prove ownership with a DNS TXT record before it becomes usable. responses: '201': description: Domain created content: application/json: schema: $ref: '#/components/schemas/SipDomainResponseDto' '400': description: Invalid hostname, or domain limit reached content: application/json: schema: $ref: '#/components/schemas/ProblemDetails' '401': description: Authentication failed or API key is missing content: application/json: schema: $ref: '#/components/schemas/ProblemDetails' '403': description: Custom SIP domains are not enabled for this organization content: application/json: schema: $ref: '#/components/schemas/ProblemDetails' '409': description: Hostname already registered content: application/json: schema: $ref: '#/components/schemas/ProblemDetails' '500': description: Server error components: schemas: SipDomainRequestDto: required: - domain type: object properties: domain: minLength: 1 type: string description: >- Hostname to register, e.g. "calls.example.com". Lowercased and stored without a trailing dot. Wildcards, IP addresses, ports and schemes are not accepted. additionalProperties: false description: >- Request to add a custom SIP domain for registered inbound calls. The domain must be a hostname you control; you prove ownership with a DNS TXT record before it becomes usable. SipDomainResponseDto: required: - createdTime - dns - domain - exampleSipUri - id - lastUpdateTime - orgId - status type: object properties: id: type: string description: >- Unique identifier of the domain record. Pass it as sipDomainId when registering a call. format: uuid orgId: minLength: 1 type: string description: Organization that owns the domain. domain: minLength: 1 type: string description: Normalized hostname. status: allOf: - $ref: '#/components/schemas/SipDomainStatus' description: >- PendingVerification until the TXT record is found and the platform registration succeeds; Active when usable; Failed when the platform refused the domain. lastError: type: string description: >- Reason for the last failed verification or registration attempt, if any. nullable: true verifiedTime: type: string description: When the domain became Active. format: date-time nullable: true defaultAgentId: type: string description: >- Agent that answers inbound calls on this domain whose SIP user part is not a registered call id. Null means such calls are rejected with SIP 404. nullable: true defaultAgentName: type: string description: Display name of the default agent, when set. nullable: true createdTime: type: string description: Timestamp when the domain was added. format: date-time lastUpdateTime: type: string description: Timestamp of the last change. format: date-time exampleSipUri: minLength: 1 type: string description: Example of the SIP URI registered calls will get on this domain. dns: allOf: - $ref: '#/components/schemas/SipDomainDnsInstructionsDto' description: DNS records to publish for verification and routing. routingRecordsDetected: type: boolean description: >- Result of the last routing DNS check: true when the domain already resolves to the Dasha SIP host (CNAME or copied A records). Only set by the verify endpoint. nullable: true additionalProperties: false description: >- Custom SIP domain with its verification state and the DNS records to publish. ProblemDetails: type: object properties: type: type: string nullable: true title: type: string nullable: true status: type: integer format: int32 nullable: true detail: type: string nullable: true instance: type: string nullable: true additionalProperties: {} SipDomainStatus: enum: - PendingVerification - Active - Failed type: string description: Lifecycle of a custom SIP domain used for registered inbound calls. SipDomainDnsInstructionsDto: required: - routing - sipTarget - verification type: object properties: verification: allOf: - $ref: '#/components/schemas/DnsRecordDto' description: >- TXT record proving ownership. Must exist before verification succeeds. routing: allOf: - $ref: '#/components/schemas/DnsRecordDto' description: >- CNAME from the domain to the Dasha SIP host. SIP phones and PBXs resolve the host with A records, so a CNAME is what makes sip:{callId}@{domain} reach Dasha. A CNAME cannot share its name with other records, so the domain must be a dedicated hostname. sipTarget: minLength: 1 type: string description: Dasha SIP host that the CNAME points at. additionalProperties: false description: >- DNS records the customer must publish for a custom SIP domain: one TXT record to prove ownership, and one CNAME so calls to the domain reach Dasha. DnsRecordDto: required: - name - type - value type: object properties: type: minLength: 1 type: string description: 'Record type: TXT or CNAME.' name: minLength: 1 type: string description: Fully qualified record name, e.g. "_dasha-verify.calls.example.com". value: minLength: 1 type: string description: >- Record data as it should appear in the zone, e.g. "dasha-domain-verification=abc123" or "sip.us.dasha.ai". target: type: string description: Target hostname. Set for CNAME records. nullable: true additionalProperties: false description: One DNS record the customer must create. securitySchemes: ApiKey: type: http description: API Key Authentication (Bearer {key}) scheme: Bearer OAuth: type: oauth2 flows: implicit: authorizationUrl: https://auth.dasha.ai/connect/authorize scopes: platform_api: Platform API ````