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Documentation Index

Fetch the complete documentation index at: https://docs.nixflex.com/llms.txt

Use this file to discover all available pages before exploring further.

This guide takes you from zero to a working AI agent answering real phone calls. You’ll need:

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Step 1 — Get your API key

1

Sign in to the dashboard

Open app.nixflex.com and sign in.
2

Create an API key

Go to API Keys → Create new key. Copy both the key_id and key_secret immediately — the secret is shown only once.
3

Format for requests

Authenticate every API call with:
Authorization: Bearer YOUR_KEY_ID:YOUR_KEY_SECRET
Treat key_secret like a password. Never commit it to source control or expose it in client-side code.

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Step 2 — Create an agent

An agent is the AI personality that answers calls. Each agent has a prompt, voice, language, and behaviour settings. 
curl -X POST https://api.nixflex.com/v1/agents \
  -H "Authorization: Bearer YOUR_KEY_ID:YOUR_KEY_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Test Receptionist",
    "system_prompt": "You are a friendly receptionist for Acme Dental. Greet callers, answer questions about opening hours (Mon-Fri 9am-5pm), and book appointments by collecting name and preferred date.",
    "welcome_message": "Hello, Acme Dental, how can I help?",
    "voice_id": "Dennis",
    "language": "en"
  }'
The response contains your agent_id: 
{
  "agent_id": "agent_125207e452f8714a",
  "name": "Test Receptionist",
  "status": "active"
}
Save the agent_id — you’ll attach a phone number to it next.

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Step 3 — Connect a Twilio number

Nixflex uses a BYO Twilio model. You import a number you already own in Twilio, and Nixflex configures the webhooks automatically. 
curl -X POST https://api.nixflex.com/v1/phone-numbers \
  -H "Authorization: Bearer YOUR_KEY_ID:YOUR_KEY_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "+447446466847",
    "twilio_sid": "ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    "twilio_token": "your_twilio_auth_token",
    "agent_id": "agent_125207e452f8714a"
  }'
That’s it. Nixflex points all webhooks on this Twilio number at the engine. The agent now answers when this number rings.

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Step 4 — Make a test call

Call your Twilio number from any phone. The agent will:
  1. Pick up
  2. Say your welcome message
  3. Listen, respond, handle interruptions naturally
  4. Hang up when the conversation ends or when the caller stops talking
After the call, the transcript, recording, summary, and any extracted data become available in the dashboard and via the API.

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Step 5 — Read the call back

Pull the call details: 
curl https://api.nixflex.com/v1/calls?limit=1 \
  -H "Authorization: Bearer YOUR_KEY_ID:YOUR_KEY_SECRET"
The response includes the transcript, recording URL, post-call summary, caller sentiment, and any custom data Claude extracted.

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What’s next

Outbound calls

Trigger AI calls programmatically with one API request.

Claude actions

Let your agent transfer calls, send SMS, and end calls using prompt tags.

Webhooks

Receive post-call data in your own systems automatically.

Custom functions

Let Claude call your APIs mid-call (lookup, booking, payments).