Billing & Credits

HMS Sovereign uses a credits-based billing system. You purchase credits upfront and they are consumed as you make and receive calls.

Pricing

By default an assistant runs on HMS Sovereign's platform keys — every supported provider works out of the box, with no API keys required. What you pay depends on which mode you run an assistant in:

1 credit = €0,07 (one minute of orchestration).

On managed phone numbers (numbers you claim from the platform), telephony is metered as a provider cost at carrier rates, alongside model usage. Numbers you bring on your own SIP trunk are exempt — your carrier bills you directly, exactly like BYOK for models. See Telephony costs below.

Telephony Costs

Calls on managed numbers use the platform's carrier account, so the phone legs are billed at cost — itemized per call in the cost breakdown, next to model usage:

Rates are USD carrier list prices, converted to credits with the same exchange-rate-plus-buffer applied to model usage. How the legs add up:

• A normal call uses one leg: the inbound line, for the call's duration.
• A transferred call uses two legs once connected: the inbound line keeps running for the whole conversation, and an outbound leg to the destination runs from the moment the transfer connects. Both appear as separate telephony lines in the call's cost breakdown.
• A transfer attempt that is never answered costs nothing (no outbound leg is billed — relevant with no-answer handling).
• Own trunk? Telephony lines still show on the call for transparency, but are marked exempt and never billed.

Concurrency & Fair Use

There is no concurrency fee and no per-line charge. You pay per minute, and simultaneous calls simply run.

As a fair-use guideline, we consider up to 20 simultaneous calls per account normal use. Nothing hard-blocks at that number: the guideline exists so a runaway dialer or a misfiring script can't degrade the platform for everyone else. If you expect to run more than 20 lines at once (a call center, an outbound campaign), tell us in advance and we'll make sure the capacity is there. Structurally higher volumes and guaranteed capacity (we hold lines free for you, even at platform peak) are available on contract.

Why we can do this: sustained concurrency generates minutes, and minutes are what you already pay for. Most voice platforms charge around $10 per month for every concurrent line beyond 10. We think that double-charges the same thing.

How Credits Work

1. Purchase credits - Add credits to your account via the dashboard
2. Use credits - Credits are consumed based on call duration
3. Track usage - Monitor your balance and usage in real-time

Credit Balance

Check your current balance via the API:

curl https://api.hmsovereign.com/api/v1/account \
  -H "Authorization: Bearer YOUR_API_KEY"

Response:

{
  "id": "org-uuid",
  "company_name": "Your Company",
  "minutes_balance": 500,
  "monthly_usage_minutes": 120
}

Usage Tracking

View detailed usage logs:

curl "https://api.hmsovereign.com/api/v1/usage?start_date=2025-12-01&end_date=2025-12-31" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response:

{
  "usage": [
    {
      "id": "usage-uuid",
      "duration_sec": 84,
      "created_at": "2025-12-13T10:00:00.000Z",
      "number_id": "number-uuid"
    }
  ],
  "summary": {
    "total_seconds": 7200,
    "total_minutes": 120,
    "total_cost": 8.40
  }
}

Insufficient Credits

When your balance reaches zero:

Inbound calls: An error audio message is played to the caller and the call is logged as status: rejected.

Outbound calls: The API returns 402 Payment Required:

{
  "error": {
    "code": "insufficient_credits",
    "message": "Insufficient credits to make outbound call. Please add credits in your billing dashboard."
  }
}

Adding Credits

Credits can be added through the dashboard:

1. Navigate to Settings > Billing
2. Click Add Credits
3. Select the amount
4. Complete payment

Payment methods accepted:

• Credit card (Visa, Mastercard, American Express)

Invoices

All credit purchases generate an invoice with:

• Invoice number
• Purchase amount
• VAT (if applicable, based on your location)
• PDF download

Access invoices in Settings > Billing > Invoices.

Tax Information

For EU businesses:

• If you provide a valid VAT ID, reverse charge applies (0% VAT)
• Without VAT ID, destination country VAT rate applies

To add billing information:

1. Go to Settings > Billing
2. Add your company name, address, and VAT ID
3. Information is synced to Stripe for invoice generation

Low Balance Notifications

Set up a webhook to monitor your balance and receive alerts:

// Check balance after each call via end-of-call-report webhook
app.post('/webhook', async (req, res) => {
  const account = await fetch('https://api.hmsovereign.com/api/v1/account', {
    headers: { 'Authorization': 'Bearer ' + API_KEY }
  }).then(r => r.json());
  
  if (account.minutes_balance < 100) {
    await sendAlert(`Low balance warning: ${account.minutes_balance} minutes remaining`);
  }
  
  res.status(200).send('OK');
});

Choosing a Pricing Mode

Every mode charges the same €0,07/min orchestration fee. The difference is who bills you for model usage:

• Platform keys (default). You don't manage any provider keys. Model usage is billed at cost through HMS Sovereign on top of the €0,07/min orchestration fee. This is what a new assistant uses out of the box.
• Vertex AI Live. A single all-in rate of €0,25/min for Google Gemini realtime, with nothing else to configure.
• Bring Your Own Key (optional). You supply your own provider keys, so your provider bills you directly for their usage and HMS Sovereign only charges the €0,07/min orchestration fee. Use this when you want full control over provider costs or want to use your own provider plan, features, and models. BYOK is never required.
• Local models (Whisper, Piper). Self-hosted models run free of model-usage charges; you pay only the €0,07/min orchestration fee.

Related

• Usage API
• Account API
• BYOK Setup