SIP

Exotel SIP trunking for Bolna AI voice agents

Connect an Exotel SIP trunk to a Bolna voice agent with Bolna's Exotel preset, so the agent answers and places calls on your Exotel numbers at your Exotel rates.

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Official Documentation

At a glance

How Exotel SIP fits in the stack

Best for

Making and receiving real phone calls at production scale.

Use this layer when

You need numbers, trunking, call routing, or carrier control.

Connects to

STT, LLM, TTS, and workflow actions inside the live call.

Voice Stack

Telephony is the calling layer

This provider connects Bolna to the phone network. It controls how calls start, where they route, which numbers you use, and how the audio enters your agent pipeline.

TelephonyPhone Network

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STTListener

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LLMReasoning

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TTSVoice

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ToolsActions

Last updated 25 October 2026

What is Exotel SIP used for in a Bolna voice agent?

Exotel SIP connects your Exotel numbers to a Bolna voice agent over a SIP trunk, so the agent answers and places calls on those numbers while Exotel carries the minutes. It is different from the native Exotel integration, which connects your Exotel account to Bolna as a telephony provider. Bolna's docs have no Exotel-specific SIP guide, so setup follows the general connect-your-carrier flow with the Exotel preset.

How do I set up an Exotel SIP trunk with Bolna?

In the Bolna dashboard, under Deploy, open SIP Trunks and click Create trunk. Pick Exotel and enter a trunk name and channels. The preset fills in Gateway we dial.
On the Carrier IPs step, check the signalling IPs the Exotel preset prefills. Add carrier credentials only if Exotel issued a SIP username and password for the calls Bolna places.
Add your Exotel numbers in E.164 format and click Create trunk.
In Exotel, point your numbers at sip:trunk.bolna.ai:5060 (or 15.252.21.46 port 5060 if only an IP is accepted), and allowlist Bolna's IPs 15.252.21.46 and 13.206.230.198 for outbound calls. The trunk's Overview tab lists these values under Carrier setup.
Use Test trunk to place an echo call in each direction.
Assign an agent to each number for inbound calls, and set an agent's Telephony Provider to SIP Trunk to call out from your Exotel numbers.

Field-by-field details are in the connect your carrier guide in the Bolna docs.

Which values does Exotel need from Bolna?

Setting	Value
Inbound address	`sip:trunk.bolna.ai:5060`, or `15.252.21.46` port `5060` if only an IP is accepted
Transport	UDP or TCP on port `5060`. TLS is not supported
Bolna IPs to allowlist	`15.252.21.46` and `13.206.230.198`
Audio (RTP)	UDP `30000` to `40000`, to and from `15.252.21.46`
Codecs	`PCMU` and `PCMA`. Turn off others, such as G.729
DTMF	RFC 2833
Caller ID on outbound calls	One of your trunk numbers, in E.164 with the `+`

What can you build with Exotel SIP and Bolna?

AI on your existing Exotel numbers. Route Exotel numbers to a Bolna agent without changing numbers, or set a default agent for numbers without their own.

Outbound calling on your trunk. Place single calls or batches from Exotel numbers on the trunk. Calls wait in the queue when every channel is busy.

Carrier data in the prompt. Map inbound SIP headers into prompt variables, or use one as the caller lookup key for your CSV, API or Google Sheet.

Check the carrier on its own. The trunk's Activity tab shows each failed call's SIP code and cause, and echo tests run without an agent.

For other carriers, see the generic SIP trunk page.

FAQ

Exotel SIP on Bolna: frequently asked questions

Yes. Pick Exotel on the Provider step. The preset fills in the gateway Bolna dials and prefills the signalling IPs Exotel publishes.

The Exotel integration connects your Exotel account to Bolna as a telephony provider. Exotel SIP connects your Exotel numbers to a Bolna SIP trunk, and the agent's telephony provider is set to SIP Trunk.

Allowlist both 15.252.21.46 and 13.206.230.198 for signalling. Audio runs over UDP ports 30000 to 40000 to and from 15.252.21.46.

Bolna passes P-Asserted-Identity, Diversion, Call-ID and up to 20 custom X- headers from the inbound INVITE. Map one to a variable on the agent to use it. Which headers arrive depends on what Exotel sends.

Other providers in this layer

Telephony

Exotel

Exotel lets a Bolna voice agent make and answer phone calls in India on your own ExoPhones, routed and billed through your Exotel account.

Telephony

Plivo

Plivo connects a Bolna voice agent to Indian phone numbers for inbound and outbound calls. Buy a number in Bolna or bring your own Plivo account.

Telephony

Twilio

Twilio lets a Bolna voice agent make and answer phone calls outside India. Buy a US number in Bolna or connect your own Twilio account and numbers.

Browse this layer

Keep exploring the voice stack

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Telephony

Telephony providers connect your voice agents to the phone network so they can make and receive real calls. Bolna supports managed integrations with major carriers as well as bring-your-own-carrier via SIP trunking, giving you full control over call routing, number provisioning, and cost.

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Large Language Models

The LLM is the brain of your voice agent. It understands what callers say and decides how to respond. Bolna lets you switch between models like GPT-5.4 mini, Claude and DeepSeek by changing the provider and model in your agent LLM settings, so you can tune for speed, cost or reasoning depth.

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Speech-to-Text

Speech-to-text converts what callers say into text that your LLM can process. Transcription accuracy and latency directly affect how natural a conversation feels. Bolna supports streaming STT providers optimized for telephony audio, including specialized models for Indian languages.

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Text-to-Speech

Text-to-speech turns your agent responses into spoken audio. Voice quality shapes how callers perceive your brand. Flat, robotic speech kills trust while natural, expressive voices build it. Bolna integrates with the fastest TTS providers so responses sound human and arrive without awkward pauses.

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Tools & Workflows

Tools let your voice agents take action during a call, not just talk. Book a calendar slot, look up an order through your own API, push a lead into your CRM, or trigger a multi-step automation in Zapier. These integrations turn voice agents from answering machines into workflow engines.

See where Exotel SIP fits in your production workflow

Use the demo to walk through provider selection, stack tradeoffs, and the exact workflow you want Bolna to automate.

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