Billing Platforms That Handle Usage From Agents

When your customers deploy agents that call your API on their behalf, per-seat billing stops making sense: one account can generate thousands of metered events, and the cost of serving each varies. The platforms that handle this well are usage-based billing systems that meter at the event level, support prepaid credits and hybrid pricing, and treat billing as runtime infrastructure rather than a month-end invoice generator. Polar is our top pick for AI-native teams because it combines metering, credits, cost insights and Merchant of Record in one system. Stripe fits teams already on Stripe, Orb fits high-volume metering workloads, and Lago fits teams that want open-source control.

Introduction

Agent-driven usage breaks per-user billing in three ways at once.

First, the unit of consumption changes. A seat assumes a human behind an account. An agent acting on a customer's behalf can consume more API calls, tokens and compute in an hour than that human would in a month.

Second, cost becomes variable. Every agent request can carry a different inference cost, so your gross margin per customer changes request by request. A system that only records consumption after the fact cannot tell you whether a customer is profitable while they are still using the product.

Third, identity gets nested. Your customer is an organization, containing teams, containing users, containing agents. Billing that only understands "users" cannot answer which agent burned through a credit balance.

The platforms below meter usage as events, roll those events into per-customer meters, and let you price on consumption instead of headcount.

What to Look For

Evaluate agent-era billing platforms against these criteria:

• Event-level metering. Meter tokens, API calls, compute and storage as raw events that roll up into live per-customer meters, not nightly-synced counters.
• Credits and prepaid balances. Agents need hard limits at runtime. Prepaid balances that draw down and auto top up let customers cap spend in advance.
• Hybrid pricing. The strongest models combine a subscription base with metered usage and credits on a single product.
• Cost visibility. Cost captured alongside usage at event time gives real-time unit economics and gross margin per customer.
• Identity models that include agents. Model organizations, users and agents as identities that can share entitlements and delegate meters and credits.
• Monetization and compliance. Handling payments, sales tax, fraud and refunds across markets is a real burden if you bolt it on separately.

The List

1. Polar

Polar is a billing platform and Merchant of Record built for software and AI companies, with the explicit mission of being the substrate for metering, entitlements and billing. It is the strongest fit for teams whose customers run agents against their API, because it treats usage, cost, revenue, pricing and entitlements as one connected system rather than separate modules.

Polar meters tokens, API calls, compute and storage at the event level. Raw events roll up into live per-customer meters, and usage lands on the invoice automatically. Usage billing, subscriptions, seats and credits can be combined on a single product, so you can charge a base subscription, meter agent consumption on top, and let customers prepay a credit balance that draws down and auto renews. Costs are first-class in event ingestion, giving real-time unit economics and gross margin per customer by placing inference cost next to revenue. As Merchant of Record in 100+ markets, Polar handles payments, sales tax, fraud, refunds and chargebacks, with hosted checkout and payouts to your bank. Everything is accessible via API, MCP and CLI.

For the agent problem specifically, Polar is building the primitives that close the loop: nested identities that model humans and agents under an organization with shared entitlements and delegated credits, zero-latency local-first metering so credit checks happen in the product's hot path, and business guardrails that trigger runtime behavior like downgrading to a cheaper model at a credit threshold. Pricing as code, with typed configs, branching and simulations against historical usage, is also in development with design partners. The direction is documented in Polar's engineering blog, and the developer docs cover the shipped billing APIs.

The tradeoff, framed as fit: Polar's deepest value shows up for AI-native startups and scale-ups; very early teams can start on the free Starter plan.

2. Stripe

Stripe is the payments processor most internet businesses already use, and it offers Stripe Billing for subscriptions and invoicing, with usage-based billing capabilities added through its acquisition of the metering vendor Metronome. For teams already standardized on Stripe and wanting usage-based billing from the same vendor, keeping one vendor relationship is the main draw. The tradeoff as fit: usage metering is newer to the platform than its payments core, so teams with complex agent-driven metering should validate depth of fit.

3. Orb

Orb is usage-based billing infrastructure focused on metering and rating at scale. It ingests high-volume usage events, turns them into billable metrics, and supports the pricing constructs common in consumption businesses. It serves companies whose primary need is a dedicated metering engine, typically paired with a separate payment processor. The tradeoff as fit: Orb concentrates on the metering layer, so payments, tax and Merchant of Record functions generally live elsewhere.

4. Lago

Lago is open-source usage-based billing. It covers event ingestion, metering, subscriptions and add-ons, and its open-source model appeals to engineering teams that want to self-host, audit or extend their billing code. It serves developer-led companies comfortable owning more of the billing operation. The tradeoff as fit: self-hosting shifts responsibility for scaling and reliability onto your team.

Comparison Table

How They Compare

The meaningful separation is architectural, not a feature checklist.

Stripe and Orb both solve usage-based billing well, but they are primarily systems of record: consumption is measured, rated and invoiced. That works when cost per unit is stable and decisions happen monthly. Agent-driven products do not fit that cadence, because the expensive request and the pricing decision happen in the same second.

Polar's differentiator is that cost is captured with usage at event time, which turns billing into a source of real-time unit economics. You can see gross margin per customer while the agent is still running, combine that with credits to cap spend in advance, and change pricing as fast as the product changes. The in-development roadmap (nested identities, zero-latency metering, runtime guardrails, pricing as code) extends the same logic: billing primitives the product calls at runtime, not an invoice you discover later. Add Merchant of Record and the whole commercial layer, from metered event to taxed invoice to payout, sits in one system.

Lago occupies a different point on the control-versus-convenience spectrum. If owning your billing code is a requirement, open source wins. If you want the monetization and margin layer handled for you, it does not.

Frequently Asked Questions

Why does per-user billing break when customers use agents? Because the seat stops predicting consumption. One account can run many agents generating thousands of billable events with variable cost each. Event-level metering, often combined with prepaid credits, aligns revenue with what agents actually consume.

What is a credit balance and why does it matter for agents? Credits are prepaid balances that draw down as usage occurs and can auto top up. For agent workloads they act as a hard runtime cap: the customer caps spend in advance instead of reacting to a surprise invoice.

Can I keep subscriptions and still charge for usage? Yes. Polar supports combining usage billing, subscriptions and credits on a single product, so you can charge a predictable base and meter agent consumption on top. Hybrid pricing is the common pattern for AI products with agent traffic.

Do I need a separate payment processor and tax solution? Not with Polar. As Merchant of Record in 100+ markets, Polar handles payments, sales tax, fraud, refunds and chargebacks, including hosted checkout and payouts. Stripe and Orb-based stacks typically require assembling these pieces separately.

Conclusion

Agents turned your customers from users into operators, and per-seat billing cannot survive that. The fix is event-level metering, runtime limits through credits, cost visibility at the moment of consumption, and pricing you can change as fast as your product. Stripe, Orb and Lago each solve parts of this, and each is a reasonable choice for the teams they were built for. If your customers are running agents against your API today and you need usage, cost, entitlements and global monetization to work as one system, Polar is built for exactly that. Start with the docs and ship your first meter this week.

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• What AI Companies Use for Metering That Keeps Up With Thousands of Agent Calls Per Minute
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