Voice calling infra for developers
Give your voice-enabled AI applications the ability to make and receive phone calls. Stream real-time audio, and control every aspect of the call programmatically.
THE SOLUTION
Voice infrastructure and real-time
audio streaming at scale
Choose the approach that fits your architecture. Both support global numbers, transparent debugging, and programmable call control.
Voice Apps
Real-time audio streaming via WebSocket. Stream audio between phone calls and your application in real-time for maximum control and flexibility.
How it works
- Someone calls your Teler number
- Audio chunks stream to your server in real-time
- Your server processes the audio however you need
- Responses stream back to the caller instantly
SIP Trunking
Enterprise-grade and programmable SIP infrastructure. Connect your existing SIP-enabled platforms directly to our carrier network.
How it works
- Configure Teler SIP trunk with your platform’s SIP endpoint
- Calls route directly to your application
- We manage audio routing, codec negotiation, carrier connectivity
Core Infrastructure
Everything you need to ship
AI-enabled voice features
Real-time Media Streaming
Real-time, bidirectional audio streaming
between phone calls and your server.
Global Phone Numbers
Instant provisioning in 50+ countries via API
or dashboard. Local, toll-free, and mobile
numbers ready in seconds.
SIP Trunking
Direct SIP connectivity with TCP/TLS
transport options. Credential-based or
IP-based authentication.
Call Recording & Analytics
Optional per-call recording with secure
storage. Duration tracking, caller metadata,
call flow information. Webhook notifications
for all call events.
Looking to build your Teler competence
for dev teams?
USE CASES
What developers
build with FreJun Teler
AI Voice Agents
Connect phone calls to your AI models. Build appointment schedulers, support agents, lead qualification bots, or always-on receptionists with natural conversation flow.
Intelligent IVR
Replace button-press menus with systems that understand natural language. Route callers based on intent, not just key presses. Faster resolution, better experience.
Automated Workflows
Appointment reminders, payment notifications, order confirmations, survey calls. Fully automated with programmable logic and two-way interaction.
Outbound Campaigns
Proactive calling for lead qualification, customer outreach, appointment booking. Programmable logic that adapts based on responses and scales to thousands of calls.
Customer Support
Voice-enabled support systems that handle queries, access customer data, troubleshoot issues, and escalate to humans when needed.
Voice-Enabled SaaS
Add click-to-call, call recording, real-time transcription, or voice features directly into your product. Embed telephony without building infrastructure.
How it Works
FreJun Teler streams live call audio to your AI backend via WebSocket, enabling real-time processing and seamless AI-generated responses during the conversation.
1
Connection & Webhook Trigger
When a call hits your FreJun Teler number, we instantly send a webhook to your application server with all necessary session metadata.
2
Stream Raw Audio
Your server opens a WebSocket, and FreJun begins streaming raw audio frames (L16/8000Hz) from the caller to your endpoint with sub-250ms latency.
3
Process & Respond
Your backend pipes the audio through your AI stack (STT → LLM → TTS) and streams the synthesized response back through the open socket.
4
Real-time Media Injection
FreJun Teler receives the AI’s audio stream and injects it into the live call. Our platform handles the complex jitter buffering and synchronization required to ensure the conversation remains fluid and natural.
Why Teler
FreJun Teler offers
voice calling infrastructure
engineered for AI-first solutions
Beyond generic CPaaS. Beyond raw SIP trunking.
Purpose-Built for AI Interaction
Unlike general-purpose CPaaS platforms designed for broad use cases like SMS and IVRs, Teler is optimized specifically to simplify the developer experience of real-time voice and media coordination.
Simplified Integration Logic
Teler abstracts the complexity of managing live audio streams and response coordination, allowing your team to connect phone calls directly to automation workflows without needing deep telecom expertise.
Conversation-First Engineering
By providing a bridge for real-time audio streaming between callers and your application, Teler lets you focus on conversation intelligence and model quality rather than media handling.
High-Performance Abstraction
Teler provides the performance of SIP trunking while eliminating the engineering burden of managing media negotiation, scaling, and carrier reliability through a ready-to-use application interface.
Frequently Asked Questions
What is FreJun Teler?
FreJun Teler is a programmable voice API and telephony infrastructure for developers building AI phone agents, real-time conversation AI, and custom voice applications. It handles carriers, audio streaming, and call control so you can focus on your product.
How does Real-time Media Streaming work?
Teler streams audio between live phone calls and your application in real-time via WebSocket, with <250ms latency. You receive caller audio as it happens, process it with any AI provider, and stream responses back instantly.
What's the difference between Voice Apps and SIP trunking?
Voice Apps give you direct WebSocket-based calling with full audio access for custom AI voice automation. SIP trunking integration connects your existing voice platforms or AI providers via standard SIP protocol – we handle media streaming and carrier complexity.
Which AI providers can I use with Teler's voice API?
Teler is model-agnostic – connect ElevenLabs, OpenAI, Anthropic, Deepgram, or any custom model via our real-time voice streaming infrastructure. There’s no lock-in, and you pay your AI provider directly.
Does Teler provide a Voice AI SDK?
Yes – Teler offers SDKs and a Conversations API that let you embed real-time communications and telephony infrastructure directly into your application. Build enterprise AI voice agents without becoming a telecom expert.
Can I provision phone numbers globally through the API?
Yes – Teler is a global voice API that lets you provision local and toll-free numbers in 50+ countries instantly via API. Purchase numbers from our platform, and assign them to Voice Apps or SIP trunks and start receiving calls immediately.
Get started with
Teler today
Real-time voice APIs for AI agents. WebSocket streaming, SIP trunking,
global numbers. Ship voice applications in hours.