Usage-Based Billing Software: 7 Best Tools for AI (2026)

Usage-based billing software measures what each customer consumes (tokens, API calls, minutes, generations) and turns it into invoices, credit balances, or overage charges. For an AI product, the hard part is everything around the meter: prepaid credits, limits that stop usage in real time, and collecting the money with the right tax in every country.

This guide compares seven usage-based billing platforms on those criteria: Commet, Stripe Billing, Metronome, Orb, Lago, OpenMeter, and Polar. Prices and capabilities were checked on the vendors' public pages on November 9, 2026.

Quick comparison#

How to choose usage-based billing software#

Most comparisons rank tools by feature count. For an AI product, these five questions separate them faster:

• Which consumption model do you sell? Metered overage at period end, prepaid credits, or a monetary balance. Some tools only meter and invoice; credits and balances need a ledger that someone has to own.

• Do you need to stop usage in real time? If a customer can run up a GPU bill in minutes, the billing system has to answer "is this allowed?" before the request, not at the end of the month.

• Who collects the money and the tax? A billing engine on top of your own processor leaves tax registration, filing, and disputes with you. A Merchant of Record sells on your behalf and takes them on, for a higher fee per transaction.

• How does the tool itself charge? A percentage of billing volume, a price per event, a fee per transaction, or a negotiated contract. Model it at your expected volume, not today's.

• Managed or self-hosted? Open source gives you control of the code and data, and gives you the operations work as well.

1. Commet: usage-based billing with payments and tax included#

Best for: AI and SaaS products that charge by consumption and do not want to assemble a metering engine, a payment processor, and a tax provider.

Where it shines. Every plan uses one of three consumption models: metered with overage, credits, or a prepaid balance, plus seats. For AI features, Commet keeps a catalog of 180+ models with their token prices, synced daily from the Vercel AI Gateway, and prices each request with the margin you set. Before an expensive action, a usage check tells you whether the customer can afford it. On Commet's own payment rail, Commet is the Merchant of Record: it calculates and remits tax, handles refunds and disputes, and pays you out. Businesses in 88 countries can sign up. If you already have a Stripe or dLocal account, Commet can run as the billing layer on top of it instead.

Tracking AI usage is one call:

import { Commet } from "@commet/node";

const commet = new Commet({ apiKey: process.env.COMMET_API_KEY! });

await commet.usage.track({
  customerId: "user_123",
  featureCode: "ai_chat",
  model: "gpt-4o",
  inputTokens: 1500,
  outputTokens: 300,
});

Where it falls short. Each event adds its value (one by default) to a feature; there are no SQL-defined metrics or transforms across event streams. Usage corrections apply only to the current period, so there is no retroactive backfill. On Commet's own rail customers pay by card; local payment methods require connecting your own dLocal account.

Pricing. As Merchant of Record, 5% + $0.40 per successful transaction, including payment processing and tax handling. Plans that connect your own payment providers are priced on request. See pricing.

2. Stripe Billing: usage billing on the Stripe account you already have#

Best for: teams that already process payments on Stripe and need simple per-unit metering on top of subscriptions.

Where it shines. Ecosystem and documentation. Basic usage-based billing runs on Stripe's Meters API, with up to 100 million events per month included in Billing pricing, and billing credits (credit grants) cover prepaid or promotional usage. Everything lives in the same account as your payments.

Where it falls short. You remain the seller: tax registration and filing stay with you unless you qualify for Stripe Managed Payments, Stripe's Merchant of Record offer, which adds 3.5% per transaction and is limited to digital products and businesses in North America, Europe, and Asia Pacific. For advanced usage billing, Stripe now points to Metronome, a separate product sold through sales. The Stripe Billing alternative comparison goes into detail.

Pricing. 0.7% of billing volume on pay as you go, on top of processing (2.9% + 30¢ per US card charge), according to Stripe Billing pricing.

3. Metronome: usage billing at enterprise event scale#

Best for: infrastructure and AI companies with very high event volumes and negotiated contracts.

Where it shines. SQL-based and streaming billable metrics, rate cards, commits, and credits, with contract amendments that can apply in the future or retroactively. Metronome is now part of Stripe and integrates natively with Stripe payments and cloud marketplaces.

Where it falls short. It is a metering and rating engine, not a Merchant of Record: payments, tax, and compliance remain separate vendors and your responsibility. Its depth assumes a team that will configure contracts and rate cards.

Pricing. Starter bills 0.8% of billing volume plus $0.04 per 1,000 ingested events; larger plans are custom, according to Metronome pricing.

4. Orb: the deepest metering engine#

Best for: companies whose billable metric needs custom SQL over raw events, or backdated corrections.

Where it shines. Event ingestion through the API or S3/GCS files, custom SQL metrics, backdating and backfills, prepaid credits, credit pools, and price simulations before you change pricing.

Where it falls short. Orb meters and invoices; it does not sell. Payments run through its Stripe or Adyen integrations and tax through finance and tax integrations, so you still operate a processor and a tax provider. The Orb alternative comparison covers the trade-offs.

Pricing. The Business plan costs $6 per Orb credit, which Orb says works out to about 0.60% of billing volume plus event ingestion and other metered dimensions; Enterprise is custom, according to Orb pricing.

5. Lago: open-source billing you run yourself#

Best for: teams that want to own their billing code and data.

Where it shines. Lago is open source under AGPL-3.0, so you can read and self-host it. It covers billable metrics, usage ingestion, entitlements, prepaid credits through wallets, and invoicing, with a managed Cloud option.

Where it falls short. Self-hosting makes deployment, uptime, and upgrades your job. Lago connects to your payment processor rather than processing payments, and tax integrations are an add-on, so registration and filing stay with you. The Lago alternative comparison compares it with Commet in depth.

Pricing. The open-source version is free to self-host. Lago Cloud and Premium are priced through a demo; no public price is listed on Lago pricing.

6. OpenMeter: open-source metering for AI and APIs#

Best for: engineering teams that need real-time metering and usage limits before they need invoicing.

Where it shines. Real-time, scalable metering of tokens and API calls, usage limits, and a product catalog, open source under Apache-2.0. OpenMeter is now part of Kong, and its cloud is offered as Kong Konnect Metering & Billing.

Where it falls short. It does not process payments, handle tax, or act as Merchant of Record, so it is one component of a billing stack rather than the whole stack.

Pricing. Free to self-host; the managed product starts free and is otherwise priced through sales, according to OpenMeter pricing.

7. Polar: a Merchant of Record for developers#

Best for: developers selling software and digital products who want tax handled and simple usage billing.

Where it shines. Polar is a Merchant of Record with usage-based billing built in: you ingest events, define meters, attach metered prices to products, and grant credits. Every rate is published.

Where it falls short. Its usage billing engine is new, and it lacks the SQL metrics and contract tooling of Orb or Metronome. Fees stack: international cards add 1.5%, and payouts carry Stripe's payout fees ($2 per month with active payouts, plus 0.25% + $0.25 per payout).

Pricing. Starter is 5% + 50¢ per transaction with no monthly fee; Pro ($20/month), Growth ($100/month), and Scale ($400/month) lower the rate down to 3.4% + 30¢, according to Polar pricing.

Which one fits your AI product#

AI startup with no billing stack yet. Usage is the product and you want to sell credits or a balance this week. A Merchant of Record with native consumption models, such as Commet or Polar, removes the processor and tax work; Commet adds prepaid balances priced per AI model. If you would rather own the infrastructure, self-hosted Lago or OpenMeter gives you metering without license costs, and payments and tax stay yours to solve.

SaaS adding a metered AI feature. On Stripe Billing, simple per-unit metering is reasonable to keep. When you need credits that stop usage at zero, prepaid balances, or fewer webhooks to reconcile, a platform with native consumption models saves you the ledger. The usage-based billing for AI guide shows that pattern step by step.

Enterprise with complex contracts. SQL metrics over several event streams, retroactive amendments, and commit-based contracts are what Metronome and Orb are built for. You will pair them with a processor and a tax provider, which at that scale you likely already have.

If you also need a Merchant of Record, the Merchant of Record comparison for usage-based billing covers that decision. To try Commet, the Next.js quickstart gets you to your first tracked event.