> ## Documentation Index
> Fetch the complete documentation index at: https://docs.talkifai.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Architecture Overview

> High-level technical architecture of the TalkifAI platform.

## System Architecture

TalkifAI is composed of four independently deployed services:

```
                    ┌──────────────────────────────┐
                    │       End User Browser        │
                    │   or Phone (via SIP carrier)  │
                    └──────────────┬───────────────┘
                                   │
                    ┌──────────────▼───────────────┐
                    │       TalkifAI Studio         │
                    │    (Next.js 15 - App Router)  │
                    │                               │
                    │  • User authentication        │
                    │  • Agent configuration UI     │
                    │  • Organization management    │
                    │  • LiveKit token generation   │
                    │  • Call session tracking      │
                    │  • Telephony webhooks         │
                    └──────────────┬───────────────┘
                                   │
              ┌────────────────────┼────────────────────┐
              │                    │                    │
              ▼                    ▼                    ▼
  ┌───────────────────┐  ┌─────────────────┐  ┌────────────────────┐
  │  Voice Agent      │  │  Billing        │  │  Marketing Site    │
  │  Runtime          │  │  Service        │  │  (Next.js)         │
  │  (Python/FastAPI  │  │  (Python/FastAPI│  │                    │
  │   + LiveKit)      │  │   + Redis)      │  │  • Landing pages   │
  │                   │  │                 │  │  • Public demo     │
  │  • STT/LLM/TTS    │  │  • Credits      │  │  • Marketing       │
  │  • Session mgmt   │  │  • Usage track  │  └────────────────────┘
  │  • Function calls │  │  • Auto top-up  │
  │  • Recordings     │  │  • Cost calc    │
  │  • Transcripts    │  └─────────────────┘
  └───────────────────┘
              │
              ▼
  ┌───────────────────┐
  │   LiveKit Server  │
  │   (WebRTC/SIP)    │
  └───────────────────┘
```

***

## Services

<CardGroup cols={2}>
  <Card title="TalkifAI Studio" icon="window" href="/architecture/voice-runtime">
    Main Next.js app — dashboard, agent builder, auth, API endpoints.
  </Card>

  <Card title="Voice Agent Runtime" icon="microphone" href="/architecture/voice-runtime">
    Python service running the actual voice agents on LiveKit.
  </Card>

  <Card title="Billing Service" icon="credit-card" href="/architecture/billing">
    FastAPI service managing credits, usage, and payments.
  </Card>

  <Card title="Security" icon="shield" href="/architecture/security">
    Authentication, encryption, and multi-tenant isolation.
  </Card>
</CardGroup>

***

## Database Architecture

All services share a **PostgreSQL** database (Neon serverless) via Prisma ORM.

**Key tables:**

| Table                  | Purpose                           |
| ---------------------- | --------------------------------- |
| `user`                 | User accounts                     |
| `organization`         | Tenant workspaces                 |
| `member`               | User-org relationships + roles    |
| `Agent`                | Voice agent configurations        |
| `PhoneNumber`          | BYOC phone numbers                |
| `CarrierCredentials`   | Encrypted SIP credentials         |
| `UserVoiceSession`     | Call session records              |
| `DeveloperQuota`       | Monthly usage limits              |
| `ApiKeys`              | Organization API keys (encrypted) |
| `CustomFunction`       | Custom webhook functions          |
| `PostCallAnalysisForm` | QA form definitions               |

***

## Infrastructure

| Component               | Technology        | Hosting                  |
| ----------------------- | ----------------- | ------------------------ |
| Studio Frontend/Backend | Next.js 15        | Vercel                   |
| Voice Agent Runtime     | Python + FastAPI  | Google Cloud VM          |
| Billing Service         | Python + FastAPI  | Google Cloud Run         |
| Database                | PostgreSQL (Neon) | Neon Cloud               |
| Cache                   | Redis             | Google Cloud Memorystore |
| Recordings              | GCS Buckets       | Google Cloud Storage     |
| LiveKit Server          | LiveKit Cloud     | LiveKit Cloud            |
| Status Page             | BetterStack       | BetterStack              |

***

## Scale Characteristics

| Metric                        | Value                |
| ----------------------------- | -------------------- |
| LiveKit rooms per node        | 3,000                |
| Participants per node         | 6,000                |
| Concurrent users (horizontal) | 10,000+              |
| Batch calls per day           | 100,000+             |
| DB connection pool            | 5 (Neon limit)       |
| Redis cache TTL               | 30 seconds (credits) |