Cost Tracking

Nenyax tracks the cost of every API call made during voice sessions — STT minutes, LLM tokens, and TTS characters.

How Costs Are Tracked

The agent worker logs usage events in real-time via POST /api/usage/events
Each event records the provider, service type, units consumed, and calculated cost
The backend aggregates costs for dashboards and reports

Provider Rates

Rates are defined in backend/app/cost_rates.py and can be updated in one place.

Service	Provider	Unit	Rate	Hourly Equivalent
STT	Deepgram	per minute	$0.0077	$0.46/hr
STT	AssemblyAI	per minute	$0.0078	$0.47/hr
STT	ElevenLabs	per minute	$0.0167	$1.00/hr
LLM	Google Gemini 2.5 Flash	per 1K tokens (blended)	$0.00086	~$0.86/1M tokens
TTS	Resemble AI	per character	$0.00004	$40/1M chars

The Gemini rate is a blended estimate assuming a ~3:1 input-to-output token ratio. Actual rates:

0.30/1M input tokens,

2.50/1M output tokens.

Usage Event Structure

{
  "session_id": "uuid",
  "user_id": "user-id",
  "agent_id": "agent-uuid",
  "provider": "assemblyai",
  "event_type": "stt_minutes",
  "quantity": 2.5,
  "unit_cost": 0.0078,
  "total_cost": 0.0195
}

Dashboard Views

Cost Summary

Dashboard → Costs shows:

Total cost across all sessions
This month’s cost
Breakdown by provider (pie chart)

Cost Timeline

View costs over time with daily, weekly, or monthly granularity.

Cost by Agent

See which agents cost the most, helping you optimize prompts and configurations.

Per-Session Breakdown

Dashboard → Call Logs → [Session] shows the cost breakdown for a single call:

Provider	Service	Units	Cost
AssemblyAI	STT	2.5 minutes	$0.0195
Google Gemini	LLM	1,250 tokens	$0.0011
Resemble AI	TTS	450 characters	$0.0180
Total			$0.0386

What’s Not Tracked

Nenyax currently does not track costs for:

LiveKit — connection minutes (~$0.0005/min per participant). These are billed by LiveKit directly.
Twilio — per-minute telephony charges for inbound/outbound calls. These are billed by Twilio directly.

These costs are external to the voice pipeline and must be monitored in each provider’s billing dashboard.

API Endpoints

# Cost summary
curl -H "x-user-id: your-user-id" http://localhost:8000/api/costs/summary

# Cost timeline (daily/weekly/monthly)
curl -H "x-user-id: your-user-id" "http://localhost:8000/api/costs/timeline?period=daily"

# Cost by agent
curl -H "x-user-id: your-user-id" http://localhost:8000/api/costs/by-agent

Getting Started

Architecture

Configuration

Features

Cost Tracking

Cost Tracking

How Costs Are Tracked

Provider Rates

Usage Event Structure

Dashboard Views

Cost Summary

Cost Timeline

Cost by Agent

Per-Session Breakdown

What’s Not Tracked

API Endpoints

​Cost Tracking

​How Costs Are Tracked

​Provider Rates

​Usage Event Structure

​Dashboard Views

​Cost Summary

​Cost Timeline

​Cost by Agent

​Per-Session Breakdown

​What’s Not Tracked

​API Endpoints

Cost Tracking

How Costs Are Tracked

Provider Rates

Usage Event Structure

Dashboard Views

Cost Summary

Cost Timeline

Cost by Agent

Per-Session Breakdown

What’s Not Tracked

API Endpoints