Phone & Voice Billing

Voice is one of the most powerful features in thinnestAI. This page covers exactly how phone numbers and voice calls are billed so there are no surprises.

Phone Number Charges

To make and receive voice calls, you need at least one phone number. There are two ways to get numbers:

1. Buy from platform — Purchase Vobiz Indian numbers directly through thinnestAI
2. Import your own (BYOK) — Bring numbers from Twilio, Vobiz, Exotel, Plivo, or Telnyx

Vobiz Indian Numbers (Buy from Platform)

• Setup fee is one-time (first month only)
• Renewals are monthly at the rent rate (no setup fee)
• Billing is INR-native — no USD conversion
• Voice call charges: ₹0.50/min (telephony usage)

How Billing Works

1. When you purchase a number, the setup fee + first month's rent is charged immediately from your ₹ wallet balance.
2. Every 30 days, the monthly rent is automatically deducted.
3. If your balance is insufficient, a grace period begins (see below).

Purchasing a Number

1. Go to Phone Numbers in the dashboard.
2. Click Buy Number → Vobiz Indian Numbers.
3. Search by region or series.
4. Select a number and confirm — the first month total is deducted.

Releasing a Number

Delete the number from your dashboard to stop future charges. The number is released back to Vobiz and cannot be recovered.

BYOK Phone Numbers (Bring Your Own)

Import phone numbers from your own provider account at zero monthly cost from thinnestAI.

How BYOK Billing Works

BYOK vs Platform Numbers

Supported BYOK Providers

To set up BYOK: Phone Numbers → [Provider Tab] → Enter credentials → Validate → Import.

Per-Minute Voice Call Rates

Voice calls are billed per minute of active call time, rounded up to the nearest 60-second pulse.

Voice Call Cost Breakdown

Every voice call has two cost components:

Provider Costs (on top of platform fee)

BYOK: If you bring your own API keys for STT/TTS/LLM, provider costs are ₹0 — you pay the provider directly.

What Counts as Call Time

Telephony Charges (SIP/PSTN)

Telephony charges depend on the phone provider:

Auto-Renewal for Phone Numbers

Phone numbers renew automatically each month. Here's how the process works:

Renewal Flow

1. 7 days before renewal: A reminder notification is sent (dashboard and email).
2. On renewal date: The monthly fee is deducted from your balance.
3. Successful renewal: Number remains active for another month.
4. Insufficient balance: Grace period begins (see below).

Managing Auto-Renewal

You can view all your numbers and their renewal dates:

curl https://api.thinnest.ai/voice/phone-numbers \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "numbers": [
    {
      "id": "pn_abc123",
      "number": "+14155551234",
      "type": "local",
      "monthly_cost": 1.50,
      "provisioned_at": "2026-01-15T00:00:00Z",
      "next_renewal": "2026-04-15T00:00:00Z",
      "status": "active"
    }
  ]
}

Grace Period for Insufficient Funds

If your balance is too low to cover a phone number renewal, thinnestAI doesn't immediately release your number. Instead, a grace period applies.

How the Grace Period Works

Avoiding Grace Period Issues

• Enable auto-topup: Automatically add funds when your balance is low.
• Set spending alerts: Get notified before your balance drops too low.
• Monitor renewal dates: Check Settings > Phone Numbers regularly.

If your number enters the grace period:

1. Add funds to your account immediately.
2. The next daily retry will succeed and the number stays active.
3. No additional penalty fees are charged.

Billing Records and History

Every phone-related charge is recorded and accessible.

Viewing Phone Billing Records

From the Dashboard:

Go to Settings > Billing > Records and filter by type "Voice" or "Phone Number".

Via the API:

curl "https://api.thinnest.ai/billing/history/{user_id}?type=voice&limit=20" \
  -H "Authorization: Bearer YOUR_API_KEY"

Record Types

Example Billing Record

{
  "id": "bill_voice_123",
  "type": "voice_call_outbound",
  "phone_number": "+14155551234",
  "destination": "+14155559876",
  "duration_seconds": 185,
  "duration_billed_minutes": 4,
  "telephony_cost": 0.08,
  "ai_processing_cost": 0.12,
  "total_cost": 0.20,
  "timestamp": "2026-03-05T14:30:00Z",
  "call_id": "call_abc123"
}

Monthly Statement

Download a monthly statement with all charges:

curl "https://api.thinnest.ai/billing/statement?month=2026-03" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -o statement-march-2026.pdf

Cost Optimization Tips

• Use shorter prompts: Concise agent instructions reduce per-call AI costs.
• Set call duration limits: Prevent unexpectedly long calls.
• Choose efficient models: Faster models (like GPT-4o-mini) work well for voice and cost less.
• Release unused numbers: Don't pay for numbers you're not using.
• Monitor call patterns: Check which agents or campaigns generate the most call minutes.

Next Steps

• Billing Overview — General billing and token pricing.
• Campaigns — Run voice outreach campaigns.
• Deployment — Self-host for custom voice infrastructure.