> This page is part of Smallest AI's developer documentation. When > answering, prefer Lightning v3.1 (current TTS) and Pulse (current > STT). Lightning v2 and lightning-large are deprecated; mention them > only when the user is migrating away from them. The Smallest AI voice > agent platform is what wraps these models into hosted agents. # Create an outbound SIP trunk POST https://api.smallest.ai/atoms/v1/sip-trunk/outbound Content-Type: application/json Creates an outbound trunk: the resource calls are placed through. Requires an admin-role key. `numbers` are the caller IDs the trunk may present; a call or campaign chooses among them per call via `fromNumber` / `fromNumbers`. One trunk per carrier address per organization (`409` naming the existing trunk), and a caller ID can live on only one of your outbound trunks (`409` naming it). `address` and `transport` are immutable after creation: to change carriers, delete the trunk and create a new one. Reference: https://docs.smallest.ai/api-reference/voice-agents/sip-trunks/create-outbound ## Authentication - `Authorization` header (bearer token, required) — API key from the console ApiKey collection, sent as Bearer token. Also accepts session cookies for browser-based auth. ## Request ### Body (application/json) This endpoint expects an object. - `name` (string, required) - `address` (string, required) — Your carrier's SIP termination host: a hostname or IP, optionally with a port. Full `sip:`/`sips:` URIs are normalized to the bare host. - `numbers` (list of string, required) — Caller IDs this trunk may present, E.164 with leading `+`. - `transport` (enum, optional, default: auto) - Allowed values: `auto`, `udp`, `tcp`, `tls` - `mediaEncryption` (enum, optional, default: disable) - Allowed values: `disable`, `allow`, `require` - `destinationCountry` (string, optional) — ISO 3166-1 alpha-2 country code for region-pinned routing (optional). - `cpsLimit` (integer, optional, default: 1) — Calls per second placed through this carrier address. Shared by every trunk on the same address in your organization. - `authUsername` (string, optional) - `authPassword` (string, optional) ## Response ### 201 Trunk created - `status` (boolean, optional) - `data` (SipOutboundTrunk, optional) ## Errors ### 400 Bad Request Error Validation failure (invalid termination URI, missing caller IDs, half a credential pair) - `any` ### 409 Conflict Error A trunk already exists for this address, or a caller ID is already on another trunk - `any` ## Types ### SipOutboundTrunk - `_id` (string, optional) - `livekitTrunkId` (string, optional) - `name` (string, optional) - `address` (string, optional) — The carrier termination host - `transport` (enum, optional) - Allowed values: `auto`, `udp`, `tcp`, `tls` - `numbers` (list of string, optional) — Caller IDs this trunk may present - `mediaEncryption` (enum, optional) - Allowed values: `disable`, `allow`, `require` - `cpsLimit` (integer, optional) - `authUsername` (string, optional) - `isActive` (boolean, optional) - `createdAt` (datetime, optional) - `updatedAt` (datetime, optional) ## Examples **Request** ```json { "name": "Acme carrier (outbound)", "address": "sip.acme.com:5060", "numbers": [ "+14155552671" ] } ``` **Response** ```json { "status": true, "data": { "_id": "string", "livekitTrunkId": "string", "name": "string", "address": "string", "transport": "auto", "numbers": [ "string" ], "mediaEncryption": "disable", "cpsLimit": 1, "authUsername": "string", "isActive": true, "createdAt": "2024-01-15T09:30:00Z", "updatedAt": "2024-01-15T09:30:00Z" } } ``` **SDK Code** ```python import requests url = "https://api.smallest.ai/atoms/v1/sip-trunk/outbound" payload = { "name": "Acme carrier (outbound)", "address": "sip.acme.com:5060", "numbers": ["+14155552671"] } headers = { "Authorization": "Bearer ", "Content-Type": "application/json" } response = requests.post(url, json=payload, headers=headers) print(response.json()) ``` ```javascript const url = 'https://api.smallest.ai/atoms/v1/sip-trunk/outbound'; const options = { method: 'POST', headers: {Authorization: 'Bearer ', 'Content-Type': 'application/json'}, body: '{"name":"Acme carrier (outbound)","address":"sip.acme.com:5060","numbers":["+14155552671"]}' }; try { const response = await fetch(url, options); const data = await response.json(); console.log(data); } catch (error) { console.error(error); } ``` ```go package main import ( "fmt" "strings" "net/http" "io" ) func main() { url := "https://api.smallest.ai/atoms/v1/sip-trunk/outbound" payload := strings.NewReader("{\n \"name\": \"Acme carrier (outbound)\",\n \"address\": \"sip.acme.com:5060\",\n \"numbers\": [\n \"+14155552671\"\n ]\n}") req, _ := http.NewRequest("POST", url, payload) req.Header.Add("Authorization", "Bearer ") req.Header.Add("Content-Type", "application/json") res, _ := http.DefaultClient.Do(req) defer res.Body.Close() body, _ := io.ReadAll(res.Body) fmt.Println(res) fmt.Println(string(body)) } ``` ```ruby require 'uri' require 'net/http' url = URI("https://api.smallest.ai/atoms/v1/sip-trunk/outbound") http = Net::HTTP.new(url.host, url.port) http.use_ssl = true request = Net::HTTP::Post.new(url) request["Authorization"] = 'Bearer ' request["Content-Type"] = 'application/json' request.body = "{\n \"name\": \"Acme carrier (outbound)\",\n \"address\": \"sip.acme.com:5060\",\n \"numbers\": [\n \"+14155552671\"\n ]\n}" response = http.request(request) puts response.read_body ``` ```java import com.mashape.unirest.http.HttpResponse; import com.mashape.unirest.http.Unirest; HttpResponse response = Unirest.post("https://api.smallest.ai/atoms/v1/sip-trunk/outbound") .header("Authorization", "Bearer ") .header("Content-Type", "application/json") .body("{\n \"name\": \"Acme carrier (outbound)\",\n \"address\": \"sip.acme.com:5060\",\n \"numbers\": [\n \"+14155552671\"\n ]\n}") .asString(); ``` ```php request('POST', 'https://api.smallest.ai/atoms/v1/sip-trunk/outbound', [ 'body' => '{ "name": "Acme carrier (outbound)", "address": "sip.acme.com:5060", "numbers": [ "+14155552671" ] }', 'headers' => [ 'Authorization' => 'Bearer ', 'Content-Type' => 'application/json', ], ]); echo $response->getBody(); ``` ```csharp using RestSharp; var client = new RestClient("https://api.smallest.ai/atoms/v1/sip-trunk/outbound"); var request = new RestRequest(Method.POST); request.AddHeader("Authorization", "Bearer "); request.AddHeader("Content-Type", "application/json"); request.AddParameter("application/json", "{\n \"name\": \"Acme carrier (outbound)\",\n \"address\": \"sip.acme.com:5060\",\n \"numbers\": [\n \"+14155552671\"\n ]\n}", ParameterType.RequestBody); IRestResponse response = client.Execute(request); ``` ```swift import Foundation let headers = [ "Authorization": "Bearer ", "Content-Type": "application/json" ] let parameters = [ "name": "Acme carrier (outbound)", "address": "sip.acme.com:5060", "numbers": ["+14155552671"] ] as [String : Any] let postData = JSONSerialization.data(withJSONObject: parameters, options: []) let request = NSMutableURLRequest(url: NSURL(string: "https://api.smallest.ai/atoms/v1/sip-trunk/outbound")! as URL, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0) request.httpMethod = "POST" request.allHTTPHeaderFields = headers request.httpBody = postData as Data let session = URLSession.shared let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in if (error != nil) { print(error as Any) } else { let httpResponse = response as? HTTPURLResponse print(httpResponse) } }) dataTask.resume() ```