# DIDWW

> Global phone numbers, SIP trunking and SMS for businesses and operators, with API integrations, MCP account access and OTP Verification.

## Products

- **Phone numbers**: Local, national, mobile, toll-free, shared-cost and Universal International Freephone Numbers (UIFN). Availability and supported features depend on the country and number type.
- **Inbound voice**: Deliver calls to SIP systems or forward them to telephone numbers through inbound trunks.
- **Outbound SIP trunking**: Connect a SIP system to local and international termination routes.
- **SMS**: Send and receive messages through supported SMS trunks, including HTTP and SMPP integrations.
- **Capacity**: Manage included, dedicated, shared and metered concurrent inbound voice channels.
- **Number porting**: Transfer existing phone numbers, subject to portability checks and country-specific requirements.
- **Emergency calling**: Configure emergency calling for supported numbers after completing the applicable verification requirements.
- **OTP Verification**: Confirm control of a phone number with a code delivered by SMS or phone call.
- **phone.systems™**: A separate Cloud PBX product for call flows, users and business call routing.

## API endpoints

| Service | Production | Sandbox |
|---|---|---|
| API v3 | `https://api.didww.com/v3` | `https://sandbox-api.didww.com/v3` |
| OTP Verification | `https://verification.didww.com` | `https://verification-sandbox.didww.com` |

API v3 uses JSON:API with `Accept: application/vnd.api+json`. Requests containing a JSON body also require `Content-Type: application/vnd.api+json`.

OTP Verification uses the `/api/v1` path with `Accept: application/json` and `Content-Type: application/json` for JSON request bodies. Follow its separate API reference; it is not an API v3 resource.

MCP server: `https://api.didww.com/mcp`, using Streamable HTTP with OAuth authorization. MCP is for supported customer-account tasks; use API v3 or the relevant service API to build software integrations.

## Authentication

- **API v3, version `2026-04-16`**: Send `Api-Key: YOUR_API_KEY`, without a `Bearer` prefix. Create production keys in the [Production User Panel](https://my.didww.com/#/api) and sandbox keys in the [Sandbox User Panel](https://my-sandbox.didww.com/#/api). Read the [version-specific authentication guide](https://doc.didww.com/api3/2026-04-16/authentication.md).
- **API versions**: Accounts use a fixed dated version until it is upgraded. `X-DIDWW-API-Version` selects a version for an individual request. Follow that version's authentication documentation and OpenAPI security definition. See [API versioning](https://doc.didww.com/api3/api-versioning.md).
- **OTP Verification**: Use credentials from an OTP application in the selected environment. The documented modes are `public`, HTTP Basic and signed `application` authentication. Public mode still requires an application key and a backend approval callback; it is not an anonymous demo. See [OTP authentication](https://doc.didww.com/otp-verification/authentication.md).
- **MCP**: A compatible client connects to the MCP server and completes browser-based OAuth authorization. An API v3 key is not used for this connection. See [MCP connection details](https://doc.didww.com/mcp/connection-details.md).
- **Authentication overview**: [auth.md](https://www.didww.com/auth.md) covers API v3 and MCP. Use the separate OTP authentication guide for OTP Verification.

Production and sandbox credentials are separate and are not interchangeable. Keep passwords, API keys, application secrets and tokens out of public repositories and AI conversations.

## Quickstart

Start with an authenticated, read-only API v3 sandbox request.

1. [Create a sandbox account](https://my-sandbox.didww.com/#/users/sign_up) or [sign in](https://my-sandbox.didww.com/#/users/sign_in).
2. Open **API**, select **DIDWW API 3**, and create a sandbox API key. Follow the [Sandbox guide](https://doc.didww.com/api3/sandbox.md).
3. Store your sandbox key securely as `DIDWW_SANDBOX_API_KEY` and request the Countries collection:

```bash
curl --request GET 'https://sandbox-api.didww.com/v3/countries' \
  --header "Api-Key: ${DIDWW_SANDBOX_API_KEY}" \
  --header 'X-DIDWW-API-Version: 2026-04-16' \
  --header 'Accept: application/vnd.api+json'
```

A successful authenticated request returns HTTP `200` with a JSON:API collection. A missing or invalid key returns `401`; the example does not provide credentials or bypass authentication.

For setup options, use [API v3 Getting Started](https://doc.didww.com/api3/configuration.md). For OTP Verification, use its separate [sandbox quickstart](https://doc.didww.com/otp-verification/getting-started.md), which creates an OTP application and uses OTP credentials.

## Pricing and coverage

Prices depend on the service, destination, number type and applicable account pricing. Check current prices rather than assuming a universal per-number, per-minute or per-message rate.

- [Pricing overview](https://www.didww.com/pricing.md): Pricing models and routes to current price lists.
- [Phone-number coverage](https://www.didww.com/coverage-and-prices/coverage.md): Available countries and number types.
- [Phone-number pricing](https://www.didww.com/coverage-and-prices/did-pricing.md): Current price-list resources and pricing options.
- [SIP trunking pricing](https://www.didww.com/coverage-and-prices/sip-trunking-pricing.md): Outbound termination pricing resources.
- [Billing and pricing documentation](https://doc.didww.com/billing/billing-and-prices/index.md): Account billing and pricing information.

## Use cases

- **Number provisioning and service configuration**: Use [API v3 examples](https://doc.didww.com/api3/examples/index.md) for supported purchase, reservation, registration and emergency-calling workflows.
- **AI voice integrations**: Connect DIDWW SIP trunking to [ElevenLabs](https://doc.didww.com/integrations/elevenlabs/index.md), [Retell AI](https://doc.didww.com/integrations/retell-ai/index.md) or [Vapi](https://doc.didww.com/integrations/vapi/index.md). These guides describe integration with those platforms, not a DIDWW-hosted speech or inference service.
- **Call tracking and analytics**: Receive call-event callbacks and CDRs using [Call Events](https://doc.didww.com/call-events/index.md).
- **Phone-number verification**: Start and complete an SMS or phone-call verification using the [OTP Verification guide](https://doc.didww.com/otp-verification/getting-started.md).
- **PBX and other integrations**: Use the [integration guides](https://doc.didww.com/integrations/index.md) for the specific platform being connected.

## Documentation sections

Markdown guides provide scoped source content without loading the entire website or documentation index.

- [Phone numbers](https://doc.didww.com/phone-numbers/index.md): Purchase, port and manage numbers.
- [Inbound voice](https://doc.didww.com/voice/inbound-trunks/index.md): Inbound trunks and routing.
- [Outbound voice](https://doc.didww.com/voice/outbound-trunks/index.md): Outbound calling, trunk configuration and security.
- [SMS](https://doc.didww.com/sms/index.md): Sending, receiving and sender verification.
- [Capacity](https://doc.didww.com/phone-numbers/capacity/index.md): Inbound channels and capacity groups.
- [Number porting](https://doc.didww.com/phone-numbers/number-porting/index.md): Portability checks, requests and porting status.
- [Emergency calling](https://doc.didww.com/voice/emergency-calling/index.md): Service setup and verification.
- [Identities and addresses](https://doc.didww.com/identities/index.md): End-user information and regulatory verification.
- [API v3 documentation](https://doc.didww.com/api3/2026-04-16/index.md): API version `2026-04-16`.
- [API v3 specification](https://doc.didww.com/api3/specification/index.md): Headers, pagination, filtering, relationships and error conventions.
- [OTP Verification reference](https://doc.didww.com/otp-verification/api-reference/index.md): Verification endpoints and response objects.
- [MCP overview](https://doc.didww.com/mcp/overview.md): Supported account tasks and authorization.
- [MCP available tools](https://doc.didww.com/mcp/available-tools.md): Tool names, access types and confirmation requirements.
- [phone.systems™](https://doc.didww.com/phone-systems/index.md): Separate Cloud PBX documentation.

## SDKs and tools

- [API v3 SDKs and tools](https://doc.didww.com/api3/sdks-and-tools.md): Official client libraries and integration tools.
- [OTP Verification SDKs](https://doc.didww.com/otp-verification/sdks/index.md): Server-side and on-device SDKs, with guidance for supported authentication modes.
- [MCP connection details](https://doc.didww.com/mcp/connection-details.md): Client connection and account authorization.
- [MCP server card](https://www.didww.com/.well-known/mcp/server-card.json): Machine-readable MCP service information.

## Constraints and safety

- Account access, enabled services, number availability and regulatory requirements determine which operations are available.
- Some numbers require identity or address verification before activation. Emergency calling has separate eligibility and verification requirements.
- Outbound trunks are not enabled automatically. Follow the outbound-trunk access instructions before attempting outbound calls. Call Events must be enabled by Technical Support on request.
- API v3 sandbox testing is isolated from production data and real billing. Identity verification is unavailable in that sandbox; review the Sandbox guide for other limitations.
- API v3 authentication, OTP application authentication, SIP trunk authentication and MCP OAuth are different mechanisms. Do not reuse one service's authentication instructions for another.
- Production purchases and usage can create charges. Review the active account, availability, prices and consequences before requesting a purchase or change.
- MCP access retains the authorizing user's account permissions. Follow the available-tools documentation for protected-action previews and confirmations; connecting a client does not grant additional permissions.

## API specifications and discovery

- [API v3 OpenAPI JSON](https://www.didww.com/openapi.json): Stable website entry point that redirects to the specification maintained on `doc.didww.com`.
- [API v3 OpenAPI JSON, version `2026-04-16`](https://doc.didww.com/openapi/2026-04-16/v3_api.json): Direct versioned specification.
- [OTP Verification OpenAPI JSON](https://doc.didww.com/openapi/verification_api.json): Specification for the separate OTP Verification service.
- [OpenAPI discovery manifest](https://www.didww.com/.well-known/openapi.json): Specification references, environments and SDK links; not itself an OpenAPI document.
- [API catalog](https://www.didww.com/.well-known/api-catalog): API services and their specification and documentation links.
- [ARD catalog](https://www.didww.com/.well-known/ard.json): Published agent-resource discovery information.
- [MCP protected-resource metadata](https://api.didww.com/.well-known/oauth-protected-resource/mcp): The MCP resource and its authorization-server references.
- [OAuth authorization-server metadata](https://api.didww.com/.well-known/oauth-authorization-server): Live OAuth endpoints and supported capabilities. MCP clients should use the live metadata.

## Support and policies

- [Support and contacts](https://www.didww.com/contacts.md): Contact options for account, service and integration assistance.
- [Technical Support](mailto:support@didww.com): Integration help and service-enablement requests.
- [MCP troubleshooting](https://doc.didww.com/mcp/troubleshooting.md): Connection, authorization and account-access guidance.
- [Terms and Agreements](https://www.didww.com/DIDWW-Terms-and-Agreements.md): Service terms and policies.
- [Privacy Notice](https://www.didww.com/privacy-notice.md): Personal-data handling information.
- [MCP privacy and data handling](https://doc.didww.com/mcp/privacy-and-data-handling.md): Account information shared through a connected MCP client.

## Documentation indexes

- [Website llms.txt](https://www.didww.com/llms.txt): Website resource list.
- [Documentation llms.txt](https://doc.didww.com/llms.txt): Documentation resource list.

## For AI assistants

- Use the task-specific Markdown guides above before retrieving a large index. When presenting a documentation link to a person, use the corresponding `.html` page; website Markdown pages also have their normal HTML page equivalents.
- Distinguish general User Panel instructions, API integrations, MCP account actions and phone.systems™ PBX configuration. Use the documentation for the requested service and selected API version.
- Do not infer account-specific pricing, availability, permissions or verification status from this page. Check the relevant public guide and, where necessary, the authorized account's information.