Billing is prepaid and per-minute. You top up a wallet, calls draw it down, and when it is empty the dialling stops. No subscription, no invoice at month end, no surprise.
The one failure mode that matters is running out at 2 PM on the day of a four-hundred-call batch.
The rate follows the balance
Worth understanding because it is counter-intuitive: the per-minute rate is not fixed, it is decided by the tier your top-up unlocks. Larger top-ups unlock cheaper rates, so paying more can buy disproportionately more minutes.
The practical consequence: if you are close to a threshold, topping up to it rather than just past your immediate need is straightforwardly cheaper per call. The estimator on the pricing page does this arithmetic.
The field to alert on
The wallet response carries a low-balance flag that turns true when the balance buys fewer than about thirty two-way minutes. That is the number to wire an alert to — not the rupee balance, because the rupee figure means different things at different rates.
If you are integrating, poll the wallet endpoint before starting a large batch and refuse to start below a threshold you set. Ten lines of code, and it prevents the failure entirely.
Auto-recharge
You can set a threshold, an amount and a daily cap so the wallet tops itself up when it runs low. The daily cap is the important part — it is what stops a runaway loop from draining a card.
It needs a linked payment method to actually execute; until then the preference is saved and shows as pending.
Budgeting a batch before you start it
Estimate honestly rather than optimistically:
- Number of calls × connect rate = calls that will actually bill.
- × average duration = minutes. Use your real average, not your target.
- × rate = cost. Add a third for retries.
Four hundred calls at 70% connect, 4 minutes, ₹4.5 is about ₹5,000 before retries, ₹6,700 with. Have that in the wallet before you press start rather than watching it drain.
Number rentals come from the wallet too
Easy to forget: the first month of a phone number is paid online at purchase, but every renewal is taken from the wallet at ₹500. An empty wallet on a renewal date flags the number as payment-due. Keep the renewal amount clear of your campaign budget.