If you are a real estate agent, run a real estate agency, or run a marketing agency serving real estate clients, an inbound AI voice agent can qualify buyers and sellers around the clock without you touching a phone. Here is how to build one using Telnyx.
Why Telnyx
Most AI voice agent setups require stitching together four separate pieces: an LLM provider, a third party voice or speech to text layer, a telephony provider, and an orchestration platform to tie it all together. That means four accounts, four API keys, and a mess of integration work, plus added latency at every handoff.
Telnyx combines AI infrastructure and telephony into a single platform. You get built in LLMs like GPT-4o and Gemini, built in text to speech and speech to text (including Deepgram), built in telephony, call control, SMS, fax, and storage, all under one roof. Because everything runs on the same infrastructure instead of bouncing between separate services, latency stays low.
Step 1: Set Up Your Account and Number
Sign up at Telnyx and verify your account first. Then add balance. Starting with around $30 is a reasonable buffer.
Next, purchase a phone number:
Go to Voice Suite, then Phone Numbers. Choose your country and the features you need. For most use cases, voice and SMS are enough. Search numbers, add one to your cart (US numbers typically run about $1 upfront). Go to Orders to verify the number once purchased.
If Telnyx does not have numbers available for your country, you can request one and they will source it for you.
Step 2: Create Your AI Assistant
Head to the AI Suite, go to Assistants, and create a new assistant. You will see two options:
Conversational workflow: a more advanced, node based setup similar to something like n8n, better suited for complex logic. Single prompt: a straightforward, prompt based assistant, which is the better starting point for most people.
Choose single prompt and start from blank rather than one of the templates (insurance verification, healthcare FAQ, high intent lead screener, and so on), since building it yourself gives you full control.
From here you will see estimated voice latency and estimated cost, both of which update as you configure the agent.
Naming and Model Selection
Give your assistant a name. In this example, the agent is named Alex, built as a real estate inbound agent. For the model, GPT-4o is the strongest option after testing the alternatives, though Gemini is also solid. You do not need to bring your own API key since Telnyx has this built in.
Greeting and Prompt
Set the greeting mode so the assistant speaks first, for example: "Hello, this is Alex. Are you looking to buy or sell real estate?"
For the system prompt, you can use Claude to generate it. A prompt like "I want to build an AI voice agent for real estate inbound for a real estate agent selling real estate in New York, give me the introduction message and give me the prompt" will produce a ready to use prompt you can paste directly into Telnyx. You can also add dynamic variables like current time if relevant, though it is often unnecessary for a simple qualifying agent.
Step 3: Configure the Hangup Tool
Telnyx includes a default hangup tool that detects phrases like "goodbye" or "bye" and ends the call gracefully with a closing message. Since the default tool cannot be edited directly, clone it first (Tools, then AI Tools, then Clone), select the cloned version in your assistant, and delete the original reference.
Step 4: Add a Knowledge Base
Create a knowledge base for your agent so it can answer questions grounded in your actual business information:
Choose your region (for example, EU if you are based there). Create a bucket and upload your website URL. You can also upload files directly, such as a PDF. One useful trick is asking Claude to build a knowledge base PDF based on your website content, then uploading that PDF alongside your URL. Set the maximum number of results (the default is generally fine, though 4 or 5 works well too).
Step 5: Configure the Voice
Under Voice settings:
Set language and region (English, United States, for example). Choose gender and a specific voice. For an agent named Alex, a high energy voice option fits well. Set language boost, speech speed, and expressive mode (to bring out natural emotion in responses). Add a pronunciation dictionary if you need control over how specific words are said. You can preview a sample voice clip before committing.
For transcription, the recommended model and language settings (English, if operating in the US) work well out of the box.
Step 6: Integrations (Optional)
If you use a CRM like Zoho, or tools like Jira or Calendly, Telnyx supports integrations, along with MCP server support. For a simple lead qualifying agent, this step can be skipped entirely.
Step 7: Assign a Number and Go Live
This is where the agent becomes usable:
Go to Calling and click Assign Number. Select the verified number from Step 1. Configure voicemail detection for outbound calls if needed (not required for inbound only). Enable or disable call recording depending on your compliance needs (GDPR, HIPAA, or others). Configure inbound and outbound voice profiles as needed, then save.
You can also enable messaging on the same number if you want SMS support, and enable a website widget if you want unauthenticated web calls in addition to phone calls.
Step 8: Test It
Before going live, use the built in test call feature to talk to your assistant directly. In a real test run, the agent walked a caller through qualifying questions naturally:
What type of property (apartment, condo, house, townhouse) Which neighborhood or borough Approximate budget Mortgage pre-approval status Move-in timeline Whether they have worked with a buyer's agent before Preferred next step (call, video consultation, or in-person meeting) and scheduling Name and phone number for follow-up
The conversation flowed naturally from question to question, confirmed details back to the caller, and ended with a scheduled next step, all without a human on the line.
Monitoring Performance
Once live, the AI Suite dashboard shows total call minutes, connected calls, total calls, average call duration, and total cost, so you can track usage and ROI at a glance.
Going Live
Once your number is assigned and confirmed, calls to that number route directly to your AI voice agent. Add the number to your website, and you have a fully functioning inbound real estate qualifying agent running 24/7.
Telnyx works especially well for the US market, though it supports other countries too. If you are handling any volume of inbound real estate inquiries, this setup can capture and qualify leads that would otherwise go to voicemail.