Usage and Billing
Synthflow uses usage-based billing, meaning you only pay for what you use. This page explains how we measure usage and how charges appear on your invoice.
How calls are billed
Phone calls are billed by the minute. We measure the actual duration of each call and aggregate usage before reporting to Stripe for billing.
Minute aggregation
Rather than rounding each individual call, we use a carryover system that aggregates seconds across calls. This ensures you’re billed fairly for your actual usage.
Here’s how it works:
In this example, four calls totaling 125 seconds resulted in 2 billed minutes, which is accurate since 125 seconds equals 2 minutes and 5 seconds.
Failed calls are not billed. If a call fails due to a system error, invalid configuration, or network issues, you won’t be charged.
Per-minute rates
The per-minute rate varies based on your plan and configuration:
- Pay As You Go: $0.15–0.24 per minute
- Enterprise: Custom rates based on your agreement
For PAYG, the exact rate depends on:
- LLM: Different language models have different costs
- Voice engine: Premium voices may have higher rates
- Telephony setup: Rates vary by carrier and destination country
Check your specific pricing in Settings > Plan & Billing.
How chat is billed
Chat messages with AI agents follow a similar usage-based model. Messages are metered and billed according to your plan’s rates. The exact pricing depends on the complexity of the interaction and the underlying model used.
Billing thresholds
For Pay As You Go customers, we use billing thresholds to ensure timely invoicing as your usage grows.
How thresholds work
When your unbilled usage reaches $200, an invoice is automatically generated and charged to your payment method. This prevents large surprise charges at the end of the month and keeps your account in good standing.
Billing thresholds do not apply to Enterprise plans, which have custom billing arrangements.
Example
If you’re a PAYG customer and your usage reaches $200 mid-month:
- An invoice is generated for the $200 in usage
- Your payment method is charged
- Usage tracking resets and continues accumulating toward the next threshold or month-end
You may receive multiple invoices in a single month if your usage is high.
Monitoring usage
Your current minute usage is displayed in the sidebar, giving you visibility into your consumption at a glance.
For agency accounts with subaccounts, you can view usage breakdowns per subaccount in the Agency dashboard.
A dedicated usage dashboard with detailed analytics is coming soon. This will provide historical usage data, trends, and more granular breakdowns.
Billing cycle
Invoices are generated:
- Monthly on your billing anniversary date
- At threshold when unbilled usage reaches $200 (PAYG only)
- On demand for add-on purchases
All invoices are available in the Billing Portal under Settings > Plan & Billing.
FAQ
Are failed calls charged?
No. You’re only charged for successful calls that connect. Calls that fail due to errors, invalid numbers, or system issues are not billed.
How do I see my current usage?
Your current minute usage is shown in the sidebar. For detailed usage history, check the Billing Portal in Settings > Plan & Billing.
Why did I receive multiple invoices this month?
If your usage exceeded the $200 billing threshold, an additional invoice was generated mid-month. This is normal for high-volume usage and helps avoid large end-of-month charges.
Can I set usage alerts?
Usage alerts are not yet available but are on our roadmap. For now, monitor your usage through the sidebar indicator.
How is international calling priced?
International calls may have different per-minute rates depending on the destination. Check your specific rates in Settings > Plan & Billing or contact support for details.
Do carryover seconds reset?
Carryover seconds accumulate throughout your billing period. At the end of each billing cycle, any remaining carryover is included in that period’s final invoice.
