Sinch Elastic SIP Trunking API

Overview

The Sinch Elastic SIP Trunking (EST) API lets you programmatically provision SIP trunks and route voice traffic between customer infrastructure and the PSTN. The core workflow is: create a trunk, authorize it (ACL or credentials), attach endpoints, assign phone numbers.

Agent Instructions

Before generating code, gather from the user (skip any item already specified in the prompt or context):

1. Direction — inbound (receive calls from PSTN), outbound (send calls to PSTN), or both?
2. Auth method for the trunk (if outbound or both) — ACL-based (static IPs) or Credential-based (digest auth / dynamic IPs)?
3. Endpoint type (if inbound or both) — Static endpoint (fixed IP/port) or Registered endpoint (SIP UA registers dynamically)?
4. Approach — SDK or direct API calls (curl/fetch/requests)?
5. Language — for SDK: Node.js. For direct API: any language, or curl. Python, Java, and .NET must use direct HTTP — only Node.js has SDK support.

When the user chooses SDK, refer to the sinch-sdks skill for installation and client initialization, then to the API references linked in References.

When the user chooses direct API calls, refer to the API references linked in References for request/response schemas.