How Credits Work
Understanding the credit deduction flow for voice calls.
Credit Deduction Flow
Every voice call follows this billing flow:
1. Pre-Call Balance Check
When you start a call (web, phone, widget, or WhatsApp), osmTalk checks your balance:
Balance >= ₹10 → Call proceeds
Balance < ₹10 → HTTP 402: "Insufficient credits"2. During the Call
While the call is active, the voice bot collects usage metrics in real-time:
- Prompt tokens — LLM input tokens consumed
- Completion tokens — LLM output tokens generated
- TTS characters — Characters converted to speech
- Duration — Total call length in seconds
No credits are deducted during the call.
3. After the Call
When the call ends, osmTalk:
- Calculates the total cost based on the agent's provider configuration and actual usage
- Deducts credits atomically — if balance is insufficient, the call is marked as "billing failed"
- Records a transaction for your billing history
Example
A 5-minute phone call using GPT-4o + Deepgram:
LLM: 2,400 tokens → ₹2.20
STT: 5 minutes → ₹2.63
TTS: 1,800 chars → ₹3.30
SIP: 5 minutes → ₹7.03
─────────────────────────
Total deducted: ₹15.16Billing Status
Each call has a billing status visible in your Call Logs:
| Status | Meaning |
|---|---|
charged | Credits successfully deducted |
pending | Call in progress, not yet billed |
failed | Insufficient credits at deduction time |
free | Zero-cost call (no metrics or very short) |
Promotional Credits
osmTalk supports two types of credit balances, both visible as separate cards on the Billing page:
| Balance Type | Description |
|---|---|
| General Credits | Credits added via top-up (paid) |
| Promotional Credits | Credits from coupon codes |
Deduction Order
When a call is billed, credits are deducted in this order:
1. Promotional Credits (promo balance) → deducted first
2. General Credits (paid balance) → used when promo is exhaustedThis means coupon credits are always consumed before any paid credits, maximising the value of your promotions.
The minimum account balance required to start a call is ₹10 (combined across promo and general credits).
Currency
All credits are in INR (₹). Provider costs (in USD) are converted at the current rate (₹94/USD).