Voicegain Telephony Bot API

Build LLM-Powered AI Voice Agents in Minutes

Build & Deploy AI Voice Agents rapidly with Voicegain Telephony Bot API. Connect a LLM Chatbot to telephony & speech resources. Replace your legacy Touchtone or Speech-Enabled IVR.

Trusted by Companies building amazing products
Core Features
Core Capabilities That Set Voicegain Apart
Own the Voice Stack

Control the entire pipeline — telephony, STT, and AI — with no third-party dependencies.

In-House Trainable STT

Use our proprietary ASR or train custom models for domain-specific accuracy.

In-House SIP Telephony

Skip external platforms. Voicegain runs on its own SIP infrastructure for full control.

Bring Your Own LLM

Integrate any large language model (OpenAI, Cohere, local LLMs) for flexible deployments.

About
Introduction to the Telephony Bot API

Generative AI is disrupting customer service. Large language models can understand and conduct human conversations at scale. Voicegain can help you deploy Generative AI powered voice assistant that can replace traditional tree-based IVRs and act as an AI Coach to your frontline call center staff. 

Easy to Use
YAML Declarative IVR
Any Backend Language
FreeSWITCH & Asterisk
Hints & Grammars
Any Bot Framework
Bring Your CPaaS
Buy Phone Numbers
High Accuracy Models
Multilingual TTS
Replace Your Legacy IVR
The Era of Touchtone Is Over.

Today’s callers expect smart, natural conversations — not robotic menus or endless button-pressing. Legacy IVRs frustrate users, increase drop-offs, and slow down support. It’s time for a smarter solution.

Traditional IVR
vs.
Modern AI Voice Agent
Multi-step menu trees
vs.
Direct, intelligent responses
Limited to keypress or keywords
vs.
Understands natural speech
Repeats info, no memory
vs.
Remembers context and intent
High drop-off, poor experience
vs.
Faster, smoother user journey
Hard to scale or personalize
vs.
Easy to adapt and fine-tune
Complex to update and maintain
vs.
Dynamic flows via API or YAML
USE CASES
Real-World Use Cases for AI Voice Agents

Voicegain powers fast, flexible phone automation across tasks, funnels, and support flows — trusted in healthcare, retail, finance, and more.

Call Centers

Share delivery updates, ETA changes, and alert customers to status changes or delays.

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Order Confirmation

Verify orders for products, services, or food delivery — and send real-time updates.

Lead Capture

Collect caller details, qualify interest, and pass leads directly to your CRM or sales team.

Knowledgebase FAQs

Resolve common questions instantly using synced content from your support or help desk tools.

Debt Collection

Trigger payment reminders, provide account status, and escalate unpaid cases when needed.

Appointments

Schedule, confirm, or reschedule bookings, all in a single phone interaction.

HOW IT WORKS
From Call to Response — Under Your Control

Build exactly what you need, where you need it — with nothing hidden, nothing locked in.

01

Build

Create your bot using your preferred LLM framework — Langchain, Flowise, OpenAI, or custom logic.

02

Connect

Start a SIP or PSTN call. Voicegain handles the signaling, media, and live audio stream.

03

Launch

Process speech with STT, generate replies using your AI, and respond using TTS — instantly.

INTEGRATIONS & DEV STACK
Integrate Seamlessly with Your Voice Stack

Voicegain works with your existing contact center, CPaaS, and AI tools. If it supports SIP INVITE or SIP REFER, it integrates.

Contact Center

Tested with leading platforms — compatible with any system that initiates a SIP INVITE.

CPaaS

Works with any CPaaS provider that supports SIP INVITE or SIP REFER.

LLMs & Bot Frameworks

Fully compatible with LLMs and conversational AI frameworks — no vendor lock-in.

SECURITY & INFRASTRUCTURE TRUST
Built to Support Enterprise-Grade Security

We protect your voice data — and give you full control over your logic and compliance layer.

Encrypted audio streams
SOC 2 Type II certified infrastructure
HIPAA-ready processing pipeline
On-premise or private cloud deployment
Role-based access & encryption
Built-in monitoring,logs & audit trails
WHY VOICEGAIN
Make Voicegain the Core of Your Voice AI Stack

Built on experience. Trusted in production. Made for developers.

15+ Years of Experience

We’ve been building and refining voice infrastructure since before LLMs were a thing.

Made for Builders

Our platform is made for engineers — not sales decks, not lock-ins, not hand-holding.

Trusted Across Industries

Powering production systems in healthcare, telecom, enterprise, and much more.

Pricing
Predictable Pricing, No Surprises

Transparent, usage-based billing. Only pay for what you stream, transcribe, and speak.

Standard

$0.03/min

Standard TTS
Inhouse Voicegain STT
Inhouse Voicegain SIP Stack
Connect to your LLM framework
Request a Demo

Premium

$0.06/min

Premium Neural TTS
Inhouse Voicegain STT
Inhouse Voicegain SIP Stack
Connect to your LLM framework
Request a Demo

Bring Your Own LLM

Use any AI engine — OpenAI, Claude, Langchain, etc. You only pay for Voicegain usage; LLM tokens are billed separately by your provider.

FAQs
What is a Voicegain Telephony Bot API?
Can I use my own CPaaS platform?
Does it support my existing bot?
How accurate is the speech recognition?
Is this for developers or non-technical users?
Can I buy phone numbers directly from Voicegain?
What our customers are saying..
Check out our blog for insights, benchmarks, sample code, and more
Voicegain Blog

Start Building AI Voice Agents with Full Stack Control