Limits and billing

Concurrency

The concurrency limit is how many calls your workspace may have live at the same time. A call is live while it is ringing or in-progress, and phone and browser calls both count.

When the limit is reached	What happens
Outbound call	It waits in the queue and is dialled when a call ends.
Inbound call	It is rejected (the caller hears the line drop).
Browser call	It is refused with all N call slots are busy: try again when a call ends.

Your limit comes from your plan, unless the Voxa team has set a different limit for your workspace. The plans Voxa starts with:

Plan	Concurrent calls	Price per minute	Agents	Members
Starter (default)	5	₹4.00	10	5
Growth	20	₹3.50	50	20
Scale	50	₹3.00	no limit	no limit

The Voxa team can change plans and prices; GET /api/v1/billing/plan returns yours.

Check your limit

curl https://voxa.abhinavyadav.in/api/v1/workspace/limits -H "X-API-Key: $VOXA_API_KEY"

{"concurrency_limit": 5, "active_calls": 2, "queued_calls": 14, "pending_request": null}

Field	Meaning
concurrency_limit	Calls you may have live at once.
active_calls	Calls ringing or in-progress now.
queued_calls	Outbound calls waiting in the queue.
pending_request	Your open request for a higher limit, or null.

Ask for a higher limit

In the console, open Limits and ask for a new limit with a reason. The Voxa team reviews it. You need the owner or admin role; API keys can’t send this request. You can ask for up to 100 concurrent calls, and have one request open at a time.

The queue

• Every outbound call is queued first, oldest first per workspace. See The queue.
• There is no limit on how many calls you can queue.
• A call waits while all slots are busy, while the agent’s calling hours are closed, or while the workspace is not active.
• A call still queued after 24 hours is canceled with expired in queue.
• Queued calls are not charged. Cancel one with POST /api/v1/calls/{id}/hangup.

Credits

Voxa is prepaid. Your balance is in paise (100 paise = ₹1). New workspaces get welcome credits (₹500 by default).

How a call is charged

Calls are billed per second of duration_seconds, at your price per minute, rounded up to the next paisa:

cost_paise = ceil(duration_seconds × price_per_minute_paise / 60)

A 14.2-second call at ₹4.00 per minute costs ceil(14.2 × 400 / 60) = 95 paise. The charge is taken when the call ends and saved on the call as cost_paise.

• Charged: outbound, inbound and browser calls that connected, for the time the agent was live.
• Not charged: time in the queue, ringing, and calls that never connected (no-answer, busy, canceled, or failed before connecting).

What happens when credits run low

Moment	Balance at or below ₹0
Placing an outbound call	402 out of credits: add credits in Billing
A queued call reaches the front	It fails with out of credits.
Inbound call	Rejected.
Browser call	Refused.

During a call, Voxa caps its length at what your balance can pay for when it starts. If that is shorter than max_duration_seconds, the call ends when the money runs out, with hangup_reason: "credits ran out".

Each call’s cap is worked out from the balance when it starts. Several calls running at once can together take the balance below zero; new calls are then refused until you top up.

Check your balance

API keys can read the balance and the ledger:

curl https://voxa.abhinavyadav.in/api/v1/billing -H "X-API-Key: $VOXA_API_KEY"

{"credits_paise": 48210, "price_per_minute_paise": 400, "minutes_left": 120.5, "low_balance": false, "plan_name": "Starter"}

low_balance is true when fewer than 10 minutes are left at your price.

curl "https://voxa.abhinavyadav.in/api/v1/billing/ledger?limit=20" -H "X-API-Key: $VOXA_API_KEY"

{
  "items": [
    {"id": "9c2e...", "at": "2026-10-01T14:44:16.300000+05:30", "kind": "call", "amount_paise": -95, "balance_after_paise": 48210, "note": "Appointment reminder · 14 s", "call_id": "00b1d622a8f04f4f8f3a3c2d9e5b7a11", "payment_id": "", "by_name": "phone"}
  ],
  "total": 212
}

Ledger kind is grant (welcome credits and other free credits), topup (a payment), call (a call’s charge, with its call_id) or adjustment (a change by the Voxa team).

Top up

Top-ups are made in the console under Billing, by the workspace owner. Choose a credit pack (larger packs include bonus credits) or a custom amount. Each payment has a GST invoice, listed by GET /api/v1/billing/invoices and downloadable as a PDF from GET /api/v1/billing/invoices/{id}/pdf.

Other limits

Limit	Default
API requests per key	120 per minute. See Rate limits.
Agents per workspace	From your plan.
Agent versions kept	10 per agent.
Webhook endpoints	20 per workspace.
Call length	max_duration_seconds, 30 to 3600 seconds per agent.