SIP Trunking quickstart

Get your first SIP Trunking calls working using Dynamic SIP Trunking APIs.

• Make outbound calls from your SIP system to PSTN
• Receive inbound calls from PSTN to your SIP system

Prerequisites

• Exotel account with KYC completed
• API Key, API Token, Account SID
• At least one Exophone (DID)
• SIP system (PBX / SBC / contact centre) with public IP or digest credentials, TCP or TLS
• Firewall ready — see Network & firewall

export EXOTEL_API_KEY="your_api_key"
export EXOTEL_API_TOKEN="your_api_token"
export EXOTEL_ACCOUNT_SID="your_account_sid"
# India: api.in.exotel.com · Singapore: api.exotel.com
export EXOTEL_SUBDOMAIN="api.in.exotel.com"

Step 1 — Create SIP trunk

POST/v2/accounts/{account_sid}/trunks

curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks" \
  -H "Content-Type: application/json" \
  -d '{
    "trunk_name": "my_trunk",
    "nso_code": "ANY-ANY",
    "domain_name": "'"$EXOTEL_ACCOUNT_SID"'.pstn.exotel.com"
  }'

Try It

Save trunk_sid.

Step 2 — Map phone number

POST/v2/accounts/{account_sid}/trunks/{trunk_sid}/phone-numbers

curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks/<trunk_sid>/phone-numbers" \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "+919876543210",
    "mode": "pstn"
  }'

Default mode is pstn. Save the numeric id from the response.

Try It

Step 3a — Whitelist IP (outbound)

Required when your system has a static egress IP.

POST/v2/accounts/{account_sid}/trunks/{trunk_sid}/whitelisted-ips

curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks/<trunk_sid>/whitelisted-ips" \
  -H "Content-Type: application/json" \
  -d '{ "ip": "<your_public_ip>", "mask": 32 }'

Try It

Step 3b — Digest credentials (optional)

Use for cloud platforms with dynamic IPs.

POST/v2/accounts/{account_sid}/trunks/{trunk_sid}/credentials

curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks/<trunk_sid>/credentials" \
  -H "Content-Type: application/json" \
  -d '{
    "user_name": "SIP_USER",
    "password": "SIP_PASS",
    "friendly_name": "voice_ai_platform"
  }'

Try It

Step 4 — Destination URI (inbound)

POST/v2/accounts/{account_sid}/trunks/{trunk_sid}/destination-uris

# IP (must be whitelisted if using IP auth)
curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks/<trunk_sid>/destination-uris" \
  -H "Content-Type: application/json" \
  -d '{
    "destinations": [
      { "destination": "<your_public_ip>:5061;transport=tls" }
    ]
  }'

Or FQDN (no IP whitelist required for destination):

curl -s -u "$EXOTEL_API_KEY:$EXOTEL_API_TOKEN" -X POST \
  "https://$EXOTEL_SUBDOMAIN/v2/accounts/$EXOTEL_ACCOUNT_SID/trunks/<trunk_sid>/destination-uris" \
  -H "Content-Type: application/json" \
  -d '{
    "destinations": [
      { "destination": "sip.yourcompany.com:5061;transport=tls" }
    ]
  }'

Try It

Step 5 — Flow with Connect applet (inbound)

1. App Bazaar → create a flow
2. Add Connect applet
3. Dial Whom: sip:<trunk_sid>
4. Map your Exophone to this flow

Path: PSTN → Exotel DID → Flow (Connect) → SIP trunk → Destination URI → your SIP

Details: Connect Applet for inbound SIP

Step 6 — Configure your SIP system

Setting	Value
SIP Domain	<account_sid>.pstn.exotel.com
Port	443 (TLS) or 5070 (TCP)
Transport	TLS (recommended) or TCP
Authentication	IP ACL and/or digest credentials

Open RTP UDP 10000–40000.

Step 7 — Test

Direction	Test
Outbound	Dial any PSTN number from your SIP system
Inbound	Call your Exophone from a mobile

Mode clarification

Flow type	Phone number mode
Connect applet (sip:<trunk_sid>)	pstn
Voicebot / other App Bazaar applets	flow

Destination URI is required in all cases.

Next

• Dynamic SIP Trunking API — full endpoint reference
• Network & firewall
• Errors & troubleshooting