API pricing

Realtime voice API, per minute

These rates cover the Karasu realtime voice session: recognition, reasoning, synthesis, and session time on one metered minute. Telephony is priced separately depending on whether you connect your own carrier or use Karasu-provided calling.

You pay only for connected realtime minutes while the AI agent is on the session. Use the product pricing page for plan tiers, concurrency, transfers, and invoice FAQs.

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Voice session rates

Billed per connected realtime minute. For how minutes are calculated, transfers, and invoices, see the full pricing page and billing FAQ.

Own telephony

$0.03 / min

You connect the carrier or SIP trunk you already use (for example Twilio, Telnyx, or your PBX). Karasu bills the AI voice session at this rate; your carrier bills you for PSTN or SIP connectivity separately.

Best when you already operate telephony in production.
Session rate stays flat at $0.03 for the Karasu voice layer.

Karasu telephony

$0.05 / min

When you use Karasu-provided telephony instead of connecting your own carrier or SIP trunk, the realtime voice API session is billed at this rate per minute.

Fewer vendors to wire up for your first production calls.
Session rate is $0.05 per minute for this combined path.

Figures shown are list rates for the realtime voice API layer. Enterprise volume, committed use, and custom concurrency may change effective pricing. Talk to sales for a formal quote.

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What the minute covers

The metered minute is the Karasu realtime voice session. It is not a separate bill for speech, model, and TTS vendors: one session, one clock, one rate class based on telephony choice.

Speech recognition and language handling in the realtime session
Model reasoning and tool use while the session is open
Natural speech output aligned with your agent configuration
One line item per metered minute on your Karasu usage bill

Billing basics

Connected calls: timing aligns with how the dashboard and billing FAQ describe active session duration.
Transfers: once a call leaves the AI agent to a human or external leg, Karasu voice minutes typically stop; telephony may continue under your carrier or Karasu path. See the pricing FAQ for detail.
Concurrency: included tiers and add-ons are listed on the main pricing page so you can size traffic before you scale.

Choosing a telephony model

Either model uses the same APIs and session controls. Start where you have the least friction, then move carriers or consolidate billing when your traffic profile is clear.

Own telephony fits when

You already have numbers, compliance workflows, or volume pricing with a carrier
You need to keep PSTN or SIP routing under your existing contracts
You are building a product where telephony is your layer and Karasu is the AI voice engine

Karasu telephony fits when

You want the fastest path from API key to a working outbound or inbound call
You prefer not to operate separate carrier accounts for early production traffic
You are prototyping and want one vendor for both connectivity and voice AI

Ready to send traffic?

Open the app for keys and usage, or read the API reference for session setup, webhooks, and telephony hooks.

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