How Aura AI Usage & Credits Work

How Aura AI Usage & Credits Work

This is the canonical explanation of how Aura AI is billed. Plans & What’s Included covers what each tier grants, and Usage & Limits covers the meters — this page is the single source of truth for the credit model itself.

Aura is auto-included — there’s no separate fee

Aura AI is auto-included with any paid Nova or Flare plan. There is no separate Aura subscription, add-on, or per-seat AI fee to buy — the moment you have a paid plan, the AI features your plan grants are available. What each tier unlocks is on the pricing page.

Two free cases, everything else is metered

Almost all Aura usage is metered per use and drawn from credits. There are exactly two exceptions:

• Voicemail transcription is always free — on every plan, every tier, it never costs credits. Its credit weight is zero: it records no usage and never draws your balance. (Call-recording transcription is a different feature, and it is metered on every tier — don’t confuse the two.)
• AI text features (summaries, sentiment, intent) are Included — free, with no credit draw, on plans that grant the entitlement. Whether your plan includes them is shown on the pricing page; on plans without the entitlement they aren’t available rather than metered.

Everything else draws credits when you use it:

Costs credits (metered per use)	Free
Call-recording transcription	Voicemail transcription (always, every plan)
Premium text-to-speech	Summaries, sentiment, intent — Included on eligible plans
Speaker diarization
Knowledge-base (RAG) queries

Different features consume credits at different rates — premium text-to-speech is charged per character, transcription and diarization per minute, knowledge-base queries per query. You see one number on your dashboard: credits used vs. included this period.

One Aura meter sits outside this table entirely: voice-agent minutes are billed in dollars, not credits — see the section below.

Your monthly allowance, then prepaid — a two-stage draw

Every plan includes a monthly Aura credit allowance that is pooled across your whole tenant — all seats share one balance, not a per-seat wallet you have to manage individually:

• Nova grants a per-seat allowance that scales with your seat count (Core grants none; Pro and Ultra scale per seat).
• Flare grants a flat per-account allowance.
• If you run both products, the allowances combine into one pooled balance.

Usage draws in two stages:

1. Included monthly allowance first — it resets at the start of each billing period.
2. Prepaid balance next — a top-up balance you load in advance, drawn from only once the monthly allowance is used up.

Current allowance sizes per tier are on the pricing page.

Voice-agent minutes are billed in dollars, not credits

Aura voice-agent minutes do not draw the credit pool. They are metered in dollars, the same way your Nova voice minutes are:

1. An included per-seat monthly allowance first — Nova Pro and Ultra each grant a per-seat allowance of voice-agent minutes that scales with your seat count. Core includes none, so agent minutes are metered from the first minute.
2. A per-minute rate after that, on a volume ladder — the per-minute rate steps down as your monthly total grows.

Because this is dollar-metered usage rather than a credit draw, voice-agent minutes do appear on your invoice as usage, exactly like voice minutes and SMS. Current allowances and per-minute rates are on the pricing page.

What happens when credits run out — pause, not surprise overage

When both the monthly allowance and the prepaid balance are exhausted, credit-burning AI features pause rather than running up an open-ended bill. Aura credits are prepaid, so an empty balance limits what the AI can do — it never turns into a charge on your invoice:

• New voice-agent calls route to the agent’s non-AI fallback destination. (Voice-agent minutes themselves bill in dollars rather than credits, but a depleted credit balance still gates the start of a new agent call.)
• An in-progress call is limited to the duration your remaining balance can fund.
• Other metered actions (call-recording transcription, premium TTS) are declined until you reload. Free features keep working — voicemail transcription, and the Included text features on eligible plans, never drew credits in the first place.
• You receive a “credits exhausted” notification.

Turn on auto-reload to top the prepaid balance back up automatically and avoid an interruption — within the monthly cap described next.

Auto-reload and its monthly cap

Auto-reload watches your total credit balance — the monthly allowance you have left plus your prepaid balance — and charges your card for another prepaid credit pack once that total falls below the threshold you set. It is the way to keep Aura running without watching the balance yourself.

The threshold is measured against the total, not against prepaid alone, so auto-reload stays quiet while a large monthly allowance is still unspent even if your prepaid balance is sitting at zero.

It runs as a daily sweep, not the instant your balance crosses the threshold, and it will make at most one top-up charge per day. That is normally invisible — a top-up lands well before the balance reaches zero — but it does mean a sudden burst of Aura usage can drain the balance to zero before the next sweep runs. If you regularly burn through more than one reload pack in a day, raise the reload amount rather than relying on the sweep to keep up.

It is not unlimited. Auto-reload will only run a fixed number of top-ups in a single calendar month. The cap is a runaway-charge guard: it stops a misconfigured reload amount, or a sudden jump in usage, from charging your card over and over in a few days.

When the cap is reached, auto-reload stops for the remainder of the calendar month and does not try again until the month rolls over. Because the cap can only be reached while your balance is already below its top-up threshold, this is the point where AI features are closest to pausing.

SIPSTACK sends an Aura auto-reload stopped — monthly limit reached notification when this happens. It is a Critical notification, and it goes to your organization’s billing audience: every active member whose role on the organization is owner, admin, or billing, plus any user individually granted billing access (partner and contact memberships are excluded).

The in-app notice names how many top-ups were used and what the cap is. Your current credit balance is in the accompanying email, not in the in-app notice — so if you want the number, open the email.

By default it arrives by bell, desktop pop-up (once you have granted your browser notification permission), and email — but only for users whose SIPSTACK account role is Owner (the Role column on Account → Users). A user whose account role is User starts with the row switched fully off and receives nothing until they turn it on, even if they are an owner of the organization. See Billing Notifications for the full defaults and how to change them.

If you receive it:

1. Top up the prepaid balance manually from Account → Billing. Auto-reload will not do it for you until next month.
2. Raise the reload amount so each top-up lasts longer. Hitting the cap usually means the reload pack is too small for how much Aura you are using, not that anything is wrong.

Auto-reload alone is not a guarantee

Auto-reload prevents interruptions only while it is still under its monthly cap. Once the cap is reached it will not top you up again that month, and the balance drains like any other account until you top it up by hand. Treat the notification as the moment to act, not as a heads-up that something will happen later.

Prepaid is a separate billing instrument

Two separate instruments — one can’t pay the other

Your prepaid Aura balance and your plan subscription are separate billing instruments. The prepaid balance funds Aura AI usage only — it can’t be applied to your Nova or Flare subscription, and your subscription payment can’t fund AI credits. Credit-funded Aura usage beyond your included allowance is debited from the prepaid balance, never added to your monthly invoice as an overage charge.

Aura credits are prepaid, and only prepaid. This is not just a policy — on a prepaid account there is no billing path that can turn credit usage into an invoice charge. Invoiced credit overage exists only for accounts placed on a postpaid capped billing arrangement, which is not how SIPSTACK accounts are set up. If you run out, the AI features pause until you top up; nothing accrues against your next invoice.

The one Aura meter this does not cover is voice-agent minutes, which are billed in dollars rather than credits and do appear on your invoice — see Voice-agent minutes are billed in dollars, not credits.

Prepaid credits never expire — they carry forward until used. To keep using Aura past the included allowance, you top up the prepaid balance in advance (or let auto-reload do it).

Prices live on the pricing page

This page describes how the model works, not the numbers. For current credit allowances per tier, what each tier includes, and which plans grant the Included text features, see sipstack.com/pricing — always the source of truth for figures.

Related

• Plans & What’s Included — what each Nova, Flare, and Aura tier grants
• Usage & Limits — every meter, where to watch it, and what happens at each limit
• Invoices — what lands on your monthly invoice (Aura credits never do; voice-agent minutes do)
• Billing Notifications — the refund, card-hold, and auto-reload alerts, and how to mute or re-route them