osmTalk Docs
Billing & Credits

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:

  1. Calculates the total cost based on the agent's provider configuration and actual usage
  2. Deducts credits atomically — if balance is insufficient, the call is marked as "billing failed"
  3. 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:      ₹15.16

Billing Status

Each call has a billing status visible in your Call Logs:

StatusMeaning
chargedCredits successfully deducted
pendingCall in progress, not yet billed
failedInsufficient credits at deduction time
freeZero-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 TypeDescription
General CreditsCredits added via top-up (paid)
Promotional CreditsCredits 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 exhausted

This 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).