SIP Trunking

Preview

SIP

Getting Started

Provision a trunk, secure it with credentials and IP ACLs, point your PBX or SBC at sip.sendexa.co, and complete your first inbound and outbound test calls.

Time to first call

~15m

With an existing PBX

SIP host

sip…

sip.sendexa.co

Ports

5060/61

UDP · TCP · TLS

Auth

Digest

+ optional IP ACL

Authentication

All REST requests use HTTP Basic Auth with your dashboard Base64 token: Authorization: Basic <token>. Auth guide →

Prerequisites

Sendexa account

Active business account with SIP Trunking enabled (Preview)
Dashboard API token for REST (Authentication)
Sufficient balance for outbound termination tests

Your infrastructure

PBX, SBC, or softswitch (Asterisk, FreeSWITCH, 3CX, etc.)
Public IP or NAT with correct SIP ALG / port mapping
Outbound firewall open to sip.sendexa.co:5060 and 5061
Optional: public SIP URI reachable for inbound DIDs

Setup workflow

Create a SIP trunk

POST /v1/sip/trunks with credentials, codecs, transport preference, and optional IP allowlist.

Configure your PBX / SBC

Point a SIP trunk or peer at sip.sendexa.co using the issued username and password. Prefer TLS 5061.

Place an outbound test call

Dial an E.164 destination through the trunk. Confirm ring, answer, two-way audio, and hangup.

Assign a DID for inbound

POST /v1/sip/numbers to attach a number and set primary/failover SIP URIs for origination.

Verify CDR

GET /v1/sip/cdr and confirm duration, direction, hangup cause, and billed minutes.

Step 1 — Create a trunk

POST

/v1/sip/trunks

A trunk is the logical SIP account that authenticates your PBX, holds capacity limits, and owns origination destinations for attached numbers.

Field	Type	Required	Description
name	string	required	Human-readable label shown in the dashboard and CDR filters.
auth.username	string	required	SIP digest username (3–64 chars, alphanumeric and _-). Must be unique per account.
auth.password	string	required	SIP digest password (min 12 characters). Returned only at creation — store immediately.
ipAllowlist	string[]	optional	CIDR list of source IPs allowed to signal. Strongly recommended for production.
codecs	string[]	optional	Allowed codecs. Default: ["PCMU","PCMA","G729","opus"]. Order is preference.
transport	string	optional	Preferred transport: "udp" \| "tcp" \| "tls". Default "tls". Your PBX may still use others if allowed.
maxConcurrentCalls	integer	optional	Simultaneous call cap for this trunk. Default depends on account plan (often 10–100).
origination.primaryUri	string	optional	Default SIP URI for inbound DIDs that do not override destination.
origination.failoverUri	string	optional	Tried if the primary URI fails (timeout, 5xx, or connection refused).

Bash

curl -X POST 'https://api.sendexa.co/v1/sip/trunks' \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Basic YOUR_DASHBOARD_BASE64_TOKEN' \
  -d '{
    "name": "Contact Centre Trunk",
    "auth": {
      "username": "cc_trunk_prod",
      "password": "S3cure-Long-Secret!"
    },
    "ipAllowlist": ["203.0.113.10/32"],
    "codecs": ["PCMU", "PCMA", "opus"],
    "transport": "tls",
    "maxConcurrentCalls": 30,
    "origination": {
      "primaryUri": "sip:inbound@pbx.example.com:5061;transport=tls",
      "failoverUri": "sip:inbound@backup.example.com:5061;transport=tls"
    }
  }'

Step 2 — Confirm the trunk

GET

/v1/sip/trunks

Bash

curl -X GET 'https://api.sendexa.co/v1/sip/trunks' \
  -H 'Authorization: Basic YOUR_DASHBOARD_BASE64_TOKEN'

response.json

{
  "success": true,
  "code": "OK",
  "data": {
    "trunks": [
      {
        "trunkId": "TRK-8c1e2b9a-4d3f-41a0-9e7c-12ab34cd56ef",
        "name": "Contact Centre Trunk",
        "status": "active",
        "sipHost": "sip.sendexa.co",
        "ports": { "udp": 5060, "tcp": 5060, "tls": 5061 },
        "auth": { "username": "cc_trunk_prod", "realm": "sendexa.co" },
        "ipAllowlist": ["203.0.113.10/32"],
        "codecs": ["PCMU", "PCMA", "opus"],
        "transport": "tls",
        "maxConcurrentCalls": 30,
        "activeCalls": 0,
        "createdAt": "2026-07-12T10:15:22.441Z"
      }
    ],
    "total": 1
  }
}

Step 3 — Point your PBX at Sendexa

Connection parameters

Setting	Value
Registrar / Proxy / Host	`sip.sendexa.co`
Port (UDP/TCP)	`5060`
Port (TLS)	`5061`
Outbound proxy	`sip.sendexa.co (same host)`
Username / Auth ID	`Your trunk auth.username`
Password	`Your trunk auth.password`
Realm / Domain	`sendexa.co`
From domain	`sendexa.co (or your verified domain)`
Register	`Optional — static IP ACL trunks often skip REGISTER`
DTMF	`RFC 2833 / telephone-event (preferred)`

Registration vs IP authentication

Most enterprise SBCs use static IP + digest without REGISTER. Softphones and some PBXes may REGISTER to receive inbound calls when they have dynamic IPs. If you use an IP allowlist and a fixed public URI for origination, registration is optional.

Sample PBX snippets

Minimal examples to reach the edge. Full production configs (NAT, SRTP, codecs) are covered in Trunk Configuration.

pjsip_sendexa.conf

; Sendexa SIP trunk — Asterisk PJSIP
[sendexa-auth]
type=auth
auth_type=userpass
username=cc_trunk_prod
password=S3cure-Long-Secret!
realm=sendexa.co

[sendexa-aor]
type=aor
contact=sip:sip.sendexa.co:5061;transport=tls
qualify_frequency=60

[sendexa-endpoint]
type=endpoint
context=from-sendexa
disallow=all
allow=ulaw,alaw,g729,opus
outbound_auth=sendexa-auth
aors=sendexa-aor
from_domain=sendexa.co
direct_media=no
rtp_symmetric=yes
force_rport=yes
rewrite_contact=yes
media_encryption=sdes
transport=transport-tls

[sendexa-identify]
type=identify
endpoint=sendexa-endpoint
match=sip.sendexa.co

[sendexa-registration]
type=registration
outbound_auth=sendexa-auth
server_uri=sip:sip.sendexa.co:5061;transport=tls
client_uri=sip:cc_trunk_prod@sip.sendexa.co
retry_interval=60
; Omit registration if using static IP ACL only

Step 4 — Outbound test call (termination)

From an extension on your PBX, dial a known good mobile in E.164 (include country code, e.g. +233…).
Confirm your dialplan routes that call via the Sendexa trunk / gateway, not another provider.
Expect normal ringback. On answer you should have two-way audio.
Hang up cleanly and note the approximate duration for CDR checks.

SIP signaling path: your PBX INVITE → sip.sendexa.co → carrier → handset.

One-way audio checklist

Enable symmetric RTP / rtp_symmetric, disable SIP ALG on the firewall, ensure UDP RTP ports (typically 10000–20000 on your side) are open, and prefer Sendexa media relay (direct_media=no) behind NAT.

Step 5 — Assign a DID (origination)

POST

/v1/sip/numbers

Attach a purchased or inventory number to your trunk and define where inbound INVITEs should be sent. Numbers must already be available on your Sendexa account (order via dashboard or sales).

Field	Type	Required	Description
number	string	required	E.164 DID you own on Sendexa, e.g. +233302123456.
trunkId	string	required	Target trunk ID returned from POST /v1/sip/trunks.
destination.primaryUri	string	required	SIP URI that receives inbound calls for this DID. Overrides trunk default if set.
destination.failoverUri	string	optional	Secondary URI if primary is unreachable.
destination.timeoutSeconds	integer	optional	Seconds to wait for 18x/200 from primary before failover (default 20).

Bash

curl -X POST 'https://api.sendexa.co/v1/sip/numbers' \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Basic YOUR_DASHBOARD_BASE64_TOKEN' \
  -d '{
    "number": "+233302123456",
    "trunkId": "TRK-8c1e2b9a-4d3f-41a0-9e7c-12ab34cd56ef",
    "destination": {
      "primaryUri": "sip:inbound@pbx.example.com:5061;transport=tls",
      "failoverUri": "sip:inbound@backup.example.com:5061;transport=tls",
      "timeoutSeconds": 20
    }
  }'

response.json

{
  "success": true,
  "code": "NUMBER_ASSIGNED",
  "message": "DID assigned to trunk for origination.",
  "data": {
    "numberId": "DID-4f91aa20-22c1-4e0b-9c3a-77b1e0d9a001",
    "number": "+233302123456",
    "trunkId": "TRK-8c1e2b9a-4d3f-41a0-9e7c-12ab34cd56ef",
    "destination": {
      "primaryUri": "sip:inbound@pbx.example.com:5061;transport=tls",
      "failoverUri": "sip:inbound@backup.example.com:5061;transport=tls",
      "timeoutSeconds": 20
    },
    "status": "active",
    "assignedAt": "2026-07-12T10:40:11.102Z"
  }
}

Step 6 — Verify CDR

GET

/v1/sip/cdr

Bash

curl -G 'https://api.sendexa.co/v1/sip/cdr' \
  -H 'Authorization: Basic YOUR_DASHBOARD_BASE64_TOKEN' \
  --data-urlencode 'trunkId=TRK-8c1e2b9a-4d3f-41a0-9e7c-12ab34cd56ef' \
  --data-urlencode 'from=2026-07-12T00:00:00Z' \
  --data-urlencode 'to=2026-07-13T00:00:00Z' \
  --data-urlencode 'limit=20'

Full field reference is in CDR & Reporting.

Firewall & network

Direction	Port / Protocol	Purpose
Outbound + Inbound	`5060/udp, 5060/tcp`	SIP signaling
Outbound + Inbound	`5061/tcp`	SIP over TLS
Outbound + Inbound	`RTP UDP (dynamic)`	Media (Sendexa may relay)
Outbound	`443/tcp`	REST API api.sendexa.co

Go-live checklist

Trunk created and status is active

SIP credentials stored in PBX secret store

IP allowlist matches your egress public IPs

TLS preferred; certificate validation enabled

Outbound test call: ring, answer, two-way audio

DID assigned with primary + failover SIP URIs

Inbound test from mobile to DID reaches your IVR/queue

CDR shows correct direction, duration, and hangup cause

maxConcurrentCalls sized for peak + headroom

Monitoring/alerts on trunk registration or call failures

Trunk Configuration

Codecs, auth modes, failover, capacity, and full PBX examples.

Origination & Termination

DID routing, CLI, STIR/SHAKEN notes, and dial patterns.

Need capacity or number inventory?

During Preview, concurrent call limits and DID stock are provisioned per account. Contact your Sendexa account team for Ghana / regional numbers and higher maxConcurrentCalls.