Connect Exotel SIP trunking with Vocallabs (Superflow B2B API)(Alpha)

10 min

This guide links Exotel SIP trunking and your Exotel DID to Vocallabs. Vocallabs publishes a B2B REST API on https://api.superflow.run/b2b/ — including createSIPCall with did, phone_number, websocket_url, and webhook_url — not the same dashboard BYO SIP trunk pattern as Vapi or ElevenLabs. Use this article for API + telephony alignment; confirm inbound SIP URIs and static egress IPs with Vocallabs if you need classic trunk destination-uris / whitelisted-ips.

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

Applicability: API-driven (token + createSIPCall / websockets / webhooks). SIP trunk routing is optional and only applies if Vocallabs provides a stable SIP target.

Docs: Vocallabs API documentation (hosted API reference and samples).

Engineering detail: vocallabs/integrations/exotel-vsip/vocallabs-exotel-voice-ai-connector.md

Quickstart: vocallabs/integrations/exotel-vsip/QUICKSTART.md

Vocallabs API (from official docs)

Topic	Detail
Base	https://api.superflow.run/b2b/
Auth	POST …/createAuthToken/ — JSON clientId, clientSecret → Bearer token for subsequent calls (docs)
SIP call	POST …/vocallabs/createSIPCall — phone_number, did, websocket_url, webhook_url, sample_rate
Outbound-style calls	POST …/vocallabs/initiateVocallabsCall — agentId, prospect_id
Webhook dial	POST …/vocallabs/initiateCallWebhook — from (DID), number (destination)
Websocket URL	GET …/vocallabs/getWebsocketUrl — query agent_id, prospect_id

Wallet / usage: GET …/getGreenBalance, transaction history — see Vocallabs docs for billing context.

How this maps to Exotel

Concept	Exotel side	Vocallabs side
DID	Exophone on SIP trunk (snippets)	Use the same E.164 as did (or from in webhook flows) where the API expects your caller / rented number
PSTN termination	Exotel edge IP:port + digest (POST …/credentials)	Not fully specified in the public reference as a single “SIP gateway hostname” like other providers — coordinate with Vocallabs for SIP leg details if createSIPCall is meant to drive traffic to Exotel
Inbound PSTN → AI	Trunk destination-uris + Flow Connect sip:<trunk_sid>	Requires a SIP origination target from Vocallabs. If their team only documents REST + websocket, implement that path first; add destination-uris when they provide a stable SIP URI

Part A — Vocallabs (auth + SIP call)

1. Create token

curl -s -X POST 'https://api.superflow.run/b2b/createAuthToken/' \ -H 'Content-Type: application/json' \ -d '{"clientId":"CLIENT_ID","clientSecret":"CLIENT_SECRET"}'

Use the returned token as Authorization: Bearer <token>.

2. Create SIP call (example shape)

Per Vocallabs API docs:

curl -s -X POST 'https://api.superflow.run/b2b/vocallabs/createSIPCall' \ -H 'Content-Type: application/json' \ -H 'Authorization: Bearer AUTH_TOKEN' \ -d '{ "phone_number": "+91XXXXXXXXXX", "did": "+91YYYYYYYYYY", "websocket_url": "wss://your-bridge.example.com/media", "webhook_url": "https://your-app.example.com/vocallabs/webhook", "sample_rate": "16000" }'

Replace did with your Exotel number in E.164 when that number is the identity Vocallabs should use for the session. websocket_url / webhook_url must be your endpoints as required by Vocallabs — see their latest field definitions.

3. Other flows

initiateVocallabsCall — agent + prospect (docs).

initiateCallWebhook — from / number for click-to-call style flows.

getWebsocketUrl — retrieve media URL for agent_id + prospect_id.

Part B — Exotel (SIP trunk + DID)

When you use Exotel as the Indian PSTN carrier for the same DID you pass to Vocallabs:

Create trunk → map DID → POST …/credentials (if your design uses SIP digest toward Exotel).

Templates: _exotel-trunk-api-snippets.md.

Optional: POST …/whitelisted-ips only if Vocallabs publishes fixed static egress IPs (mask: 32 per IP).

Inbound (only if Vocallabs gives you a SIP URI to send calls to): POST …/destination-uris toward that URI → Flow → Connect → sip:<trunk_sid> (Detailed SIP Trunking API ReferenceVoice AI / SIP trunking).

Troubleshooting

Symptom	What to check
401 on Superflow	Valid createAuthToken + Bearer header
Call fails / wrong CLI	did / from match E.164 Exotel number you own
No media	websocket_url, getWebsocketUrl, firewall to Vocallabs / your bridge
SIP vs API mismatch	Vocallabs may be API-first — confirm with their team before assuming full SIP trunk parity

References

Resource	URL
Vocallabs API docs	https://docs.vocallabs.ai/vocallabs
Exotel SIP API	https://docs.exotel.com/dynamic-sip-trunking/detailed-sip-trunking-api-reference
Exotel network / firewall	https://docs.exotel.com/dynamic-sip-trunking/network-and-firewall-configuration