DIDWW Voice and Number Management API vs Voximplant

DIDWW Voice and Number Management API

An OpenAPI 3.0.3 document with 107 operations, Markdown docs, a free sandbox and SDKs in seven languages cover number ordering and SIP trunk set-up. No per-number or per-minute price is public, API keys carry no scopes, orders have no idempotency key, and outbound calling needs an approved application. Calls travel over SIP only.

Voximplant

Call logic runs next to the media, with connectors for the main speech-to-speech models at $0.004 a minute. Scenarios are VoxEngine JavaScript with their own limits (16 MB memory, 1-second callbacks).

DIDWW Voice and Number Management API

1. Send Api-Key: <key> with no Bearer prefix, plus Accept: application/vnd.api+json, and Content-Type: application/vnd.api+json on every request with a body
2. Set X-DIDWW-API-Version: 2026-04-16 on each request and read meta.api_version in the reply. A header older than the account's version is ignored
3. Before retrying a timed-out POST /orders, list GET /orders first. The order is charged to the balance at once and no idempotency key exists
4. Stay under 20 requests a second per key. On 429 wait before retrying, since no Retry-After header is documented
5. Use fields[...], filter[...], include and page[size] (default 50, maximum 100) to keep JSON:API replies small
6. Check GET /address_requirements before buying a number. Many countries need a verified identity and address, and the sandbox cannot run identity verification
7. Create and enable a callback secret in the User Panel before relying on callbacks. Without one nothing is sent, and receivers must verify X-DIDWW-Signature

Voximplant

1. Upload a VoxEngine scenario and a rule first, then start it with StartScenarios and pass the number in script_custom_data
2. Use a service-account JWT rather than api_key in the URL
3. Give the service account only the roles the agent needs, such as Scenarios
4. Ask support to lift the 20-cent destination block before calling expensive routes