Connect Exotel SIP Trunk to LiveKit

14 min

This guide connects Exotel SIP trunking to LiveKit Cloud telephony so PSTN calls can reach LiveKit rooms and outbound calls can use Exotel as the Indian PSTN leg.

GitHub repo (reference): https://github.com/exotel/AgentStream-VoiceAIEcosystem

What you will set up

Direction	Path
Inbound PSTN → LiveKit	PSTN → Exotel DID → trunk destination URI → LiveKit SIP endpoint → dispatch → room
Outbound PSTN ← LiveKit	LiveKit outbound trunk → digest → Exotel edge IP:port → PSTN

Exotel trunk ACL: use whitelisted-ips only when LiveKit (or your network) provides a fixed static egress IP to allow. Exotel trunk does not support CIDR range allowlisting — use mask: 32 and one POST per static IP. Otherwise rely on digest (POST .../credentials).

Architecture

Inbound: PSTN → Exotel DID → destination URI on trunk → LiveKit SIP host → room → agent Outbound: LiveKit → Exotel edge IP:port (digest) → PSTN

Prerequisites

Exotel: KYC, DID E.164, API credentials, https://api.in.exotel.com.

LiveKit: Cloud project, Telephony, SIP URI from Project settings (SIP trunk setup).

Part A — LiveKit Cloud

SIP endpoint and region (inbound)

Copy SIP URI from project settings. For India pinning: {subdomain}.india.sip.livekit.cloud (region pinning).

Inbound trunk

Telephony → SIP trunks → Inbound — include your Exotel DID in E.164 (Inbound trunk).

Dispatch rule

At least one rule so calls land in a room (Dispatch rule).

Outbound trunk

address — Exotel edge IP:port from Exotel.

numbers — Exotel DID E.164.

authUsername / authPassword — same as Exotel POST .../credentials.

{
  "name": "Exotel outbound",
  "address": "YOUR_EXOTEL_EDGE_IP:443",
  "numbers": ["+9198XXXXXXXX"],
  "authUsername": "SIP_USER",
  "authPassword": "SIP_PASS"
}

Agent in the same room

OUTBOUND-EXOTEL-NOTES.md — ring without bot audio usually means no publisher in the room.

Part B — Exotel APIs

Rate limit: 200/minute. Snippets: _exotel-trunk-api-snippets.md.

Outbound SIP — three steps

Create trunk

Map DID to trunk

POST .../credentials (user_name, password) — must match LiveKit outbound trunk auth

Optional: POST .../whitelisted-ips only if LiveKit gives you a static SIP egress IP to allow — single IP, mask: 32 per entry. No CIDR range on trunk.

Inbound only: POST .../destination-uris toward your LiveKit SIP host (not required for minimal outbound-only testing).

curl -s -X POST \
  "https://${API_KEY}:${API_TOKEN}@${SUBDOMAIN}/v2/accounts/${ACCOUNT_SID}/trunks/${TRUNK_SID}/credentials" \
  -H "Content-Type: application/json" \
  -d '{
    "user_name": "SIP_USER",
    "password": "SIP_PASS",
    "friendly_name": "livekit"
  }'

Inbound SIP — destination URI on trunk

curl -s -X POST "https://${API_KEY}:${API_TOKEN}@${SUBDOMAIN}/v2/accounts/${ACCOUNT_SID}/trunks/${TRUNK_SID}/destination-uris" \
  -H "Content-Type: application/json" \
  -d '{
    "destinations": [
      { "destination": "YOUR_SUBDOMAIN.india.sip.livekit.cloud:5061;transport=tls" }
    ]
  }'

Connect applet (inbound)

Dial whom: sip:<trunk_sid> — use the trunk_sid from create trunk (not a full SIP URI). Map DID to Flow. Detailed SIP Trunking API ReferenceSIP trunk guide.

Testing

Outbound SIP was validated with correct edge IP:port, digest, and E.164; optional static-IP ACL when applicable. Audio still requires an agent in the same room as the SIP participant.

Applicability: UI-driven + developer-driven (LiveKit Cloud console for trunks/dispatch; your app/agent joins rooms). Not a single “import trunk” wizard like some providers.

Exotel edge: Signaling toward Exotel uses edge IP:port from Exotel (network and firewall). Configure IP:port as Exotel assigns — not an assumed carrier hostname.

Edge hostnames you may see (India): in.voip.exotel.com:5070 (TCP) and in.voip.exotel.com:443 (TLS). Use the exact host/IP + port + transport Exotel assigns. See _exotel-trunk-api-snippets.md.

ACL vs digest (important): Exotel trunk ACL (whitelisted-ips) is intended for static /32 IPs only (mask: 32), not CIDR ranges. If the provider/network only has CIDR/shared egress, prefer digest and coordinate with Exotel support—IP allowlisting can become the primary trust signal and cause intermittent auth/routing issues in shared egress setups.

Scope: LiveKit Cloud with Telephony enabled. See OUTBOUND-EXOTEL-NOTES.md for 403, E.164, and “no audio” patterns.

Troubleshooting

Symptom	What to check
403 / 4001	Digest; optional static-IP ACL; correct edge IP:port
Wrong format	E.164 for India
Ring, no bot	Agent + room (OUTBOUND-EXOTEL-NOTES.md)
Connect broken	sip:<trunk_sid> only in Dial whom

References

Resource	URL
LiveKit Cloud	https://cloud.livekit.io/
LiveKit SIP trunk setup	https://docs.livekit.io/telephony/start/sip-trunk-setup/
Exotel SIP API	https://docs.exotel.com/dynamic-sip-trunking/detailed-sip-trunking-api-reference