Usage-based billing for AI SaaS

Usage-based billing for AI products: tokens, credits and committed spend on one invoice

How AI-native SaaS companies meter tokens, credits and API calls in Bunny, combine them with seat fees and committed spend, and invoice it all on one subscription.

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What makes usage-based billing different for AI-native SaaS

Companies selling AI products where pricing mixes seats, credits, tokens and committed spend, and where the pricing model itself changes every few months.

  • The unit of value keeps changing

    Tokens, credits, generations, minutes, documents processed — AI products often change what they meter as the model and the market shift. Billing that hard-codes one unit has to be rebuilt each time.

  • Pure consumption pricing scares procurement

    Enterprise buyers want a predictable number on the purchase order. That pushes AI vendors toward committed spend with overage, which is a hybrid contract, not a simple meter.

  • Usage and seats on one contract

    Most AI products charge a platform or seat fee plus consumption. Billing them from two systems means two invoices, two sets of proration rules and a reconciliation problem for finance.

  • Margins depend on rating being right

    When cost of goods is inference compute, mis-rated usage is not a rounding error — it is negative gross margin on the account. Rating has to match the contract exactly, including negotiated rates.

How Bunny handles usage-based billing for AI-native SaaS

  1. 01

    Meter any unit as a usage charge

    Tokens, credits, API calls or any other unit are modelled as usage-based charges in the catalog. Usage is reported through the GraphQL API, rated against the pricing on the subscription and itemised on the invoice.

    Usage-based billing in Bunny
  2. 02

    Flat, tiered, volume or banded rates on usage

    Each usage charge carries its own pricing model, so a per-token rate can step down with volume while a per-seat fee stays flat, on the same subscription.

    Tiered vs volume pricing
  3. 03

    Committed spend plus overage as one deal

    A subscription can have any number of recurring and usage charges. A recurring commitment and a usage charge for consumption above it are quoted, signed and invoiced together.

  4. 04

    Negotiated usage rates without polluting the catalog

    Enterprise deals override the usage rate on the quote for that customer only. The catalog stays clean and the override follows the subscription into renewal.

    Quoting in Bunny
  5. 05

    Change the meter without migrating customers

    A new pricing model is a new price list. Existing subscriptions keep billing on their contracted terms until a renewal or upgrade quote moves them.

  6. 06

    Usage in the customer portal and the metrics

    Customers see consumption and invoices in the portal, and usage revenue flows into MRR, ARR and cohort analytics alongside recurring revenue rather than as a separate report.

    What hybrid pricing means

Why AI billing tends to break first

Most AI companies start with a simple meter and a card on file, which any payments tool can handle. The break comes with the first enterprise deal: a committed annual spend, a negotiated per-token rate below list, seats for the admin console, and a procurement team that wants one invoice per quarter. At that point the meter is only one of four things on the contract, and the billing tool has to know about all of them.

The pattern that holds up is to treat usage as one charge type among several on a single subscription, not as a separate product. In Bunny, a plan can carry a recurring platform fee, a recurring committed-spend charge, and a usage charge for consumption above the commitment, each with its own pricing model. The quote sets the negotiated numbers for that customer; the subscription bills them; the renewal quote starts from the live state of all three.

What to model up front

  • The unit and its granularity. Bill in thousands of tokens rather than single tokens if that is how you price; the rating handles either, but invoices are easier to read at the granularity you sell in.
  • Commitment period. Annual commitments with monthly true-up are the common enterprise shape. Bunny bills the recurring commitment on the contract schedule and rates overage per period.
  • Where discounts apply. A discount on the committed charge and a discount on the overage rate are separate decisions. Both are set on the quote and both are visible on the invoice.
  • Trial and free tiers. Free allowances are a recurring charge at zero with a usage charge above them, which keeps free and paid customers on the same catalog.

If your pricing is still settling, the useful property is that none of these choices is permanent. A price list can be retired and replaced without touching the subscriptions that were sold on it.

Usage-based billing for other industries

The same workflow, written up for other kinds of B2B SaaS. Browse all industries.

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FAQ

Frequently asked questions

How does Bunny bill for tokens or credits?
Tokens and credits are set up as usage-based charges on a plan. Your application reports usage to Bunny through the API, Bunny rates it against the flat, tiered, volume or banded pricing on the subscription, and the resulting charge appears on the invoice alongside any recurring fees.
Can we sell a monthly credit allowance with overage?
Yes. Model the allowance as a recurring charge and the overage as a usage charge on the same plan. Bunny bills the recurring amount each period and rates consumption above the allowance at the overage price.
Can enterprise customers get a custom per-token rate?
Yes. The rate is overridden on the quote for that customer, along with any discount or ramp, without creating a customer-specific product in the catalog. The negotiated rate carries through to renewal quotes.
What if we switch from credits to tokens next quarter?
Add the new plans and price lists to the catalog. Existing customers keep billing on the terms they signed; new customers sign up on the new model, and existing ones move when you send them a renewal or upgrade quote.
Does usage-based revenue show up in SaaS metrics?
Yes. Usage revenue is included in Bunny's revenue analytics alongside recurring revenue, so MRR, ARR, net revenue retention and cohort views reflect the whole contract rather than only the subscription component.