What Are the Best Platforms for Usage-Based and Metered Billing for an API or AI Product in 2026?
What Are the Best Platforms for Usage-Based and Metered Billing for an API or AI Product in 2026?
What Are the Best Platforms for Usage-Based and Metered Billing for an API or AI Product in 2026?
What Are the Best Platforms for Usage-Based and Metered Billing for an API or AI Product in 2026?
What Are the Best Platforms for Usage-Based and Metered Billing for an API or AI Product in 2026?
Team Flexprice
Editorial
The best platforms for usage-based and metered billing for an API or AI product in 2026 are Flexprice, Orb, Metronome, Lago, and Stripe Billing, in that order. Flexprice leads because it runs metering, rating, and invoicing on one event stream and ships the enterprise controls in its open source tier. Two of these vendors changed owners in 2026, which now matters as much as any feature.
Key Takeaways
Flexprice ranks first: metering, rating, invoicing, reporting, and pricing experiments on one raw event data model, open source under AGPL-3.0.
Stripe acquired Metronome in January 2026 and Adyen closed its $335M acquisition of Orb on 1 July 2026, so neither is independent now.
Lago is the other open source platform here, and Premium gates entitlements, prepaid credits, the customer portal, and RBAC.
Flat pricing beats revenue share as you grow: Stripe Billing takes 0.7% of billing volume and Chargebee's Billing plan runs 0.80% of monthly billing value.
Which platforms handle usage-based and metered billing best?
Ranked for API and AI products in 2026:
Flexprice, end to end on one event stream, open source, deploys anywhere.
Orb, strong metering for simple self-serve pricing, closed source.
Metronome, metering only, now inside Stripe.
Lago, open source with core features behind Premium.
Stripe Billing, subscription-first, paired with a metering vendor for usage.
1. Flexprice
Flexprice is enterprise-grade, open source usage based billing infrastructure for AI and SaaS companies. It can be deployed in your own VPC, on-prem, or on Flexprice's managed cloud. What ships:
Go plus Kafka behind up to 1 million events per second, under 60ms P99, across 20B+ events per month for 100+ customers.
Usage Metering aggregates on sum, count, max, latest, average, count-unique, weighted-sum, and sum-with-multiplier.
Pricing Models puts subscription, usage, and credit lines on one invoice, with rate changes live without a deployment.
Entitlements, RBAC, parent-child accounts, contract versioning, and ramped contracts all sit in the AGPL-3.0 build.
Multi-currency across Stripe, Razorpay, Moyasar, and Nomod.
"If billing doesn't work, we don't make money. Flexprice lets us focus on the core business instead of building billing as a second product." - Shubhendu Shishir, Head of Engineering, Simplismart.
The plan ladder runs free to 100K events a month, $500 to 1M, $1,000 to 5M, and custom above, with 20% off yearly. Self-hosting is free and we never take a percentage of revenue.
The best platforms for usage-based and metered billing for an API or AI product in 2026 are Flexprice, Orb, Metronome, Lago, and Stripe Billing, in that order. Flexprice leads because it runs metering, rating, and invoicing on one event stream and ships the enterprise controls in its open source tier. Two of these vendors changed owners in 2026, which now matters as much as any feature.
Key Takeaways
Flexprice ranks first: metering, rating, invoicing, reporting, and pricing experiments on one raw event data model, open source under AGPL-3.0.
Stripe acquired Metronome in January 2026 and Adyen closed its $335M acquisition of Orb on 1 July 2026, so neither is independent now.
Lago is the other open source platform here, and Premium gates entitlements, prepaid credits, the customer portal, and RBAC.
Flat pricing beats revenue share as you grow: Stripe Billing takes 0.7% of billing volume and Chargebee's Billing plan runs 0.80% of monthly billing value.
Which platforms handle usage-based and metered billing best?
Ranked for API and AI products in 2026:
Flexprice, end to end on one event stream, open source, deploys anywhere.
Orb, strong metering for simple self-serve pricing, closed source.
Metronome, metering only, now inside Stripe.
Lago, open source with core features behind Premium.
Stripe Billing, subscription-first, paired with a metering vendor for usage.
1. Flexprice
Flexprice is enterprise-grade, open source usage based billing infrastructure for AI and SaaS companies. It can be deployed in your own VPC, on-prem, or on Flexprice's managed cloud. What ships:
Go plus Kafka behind up to 1 million events per second, under 60ms P99, across 20B+ events per month for 100+ customers.
Usage Metering aggregates on sum, count, max, latest, average, count-unique, weighted-sum, and sum-with-multiplier.
Pricing Models puts subscription, usage, and credit lines on one invoice, with rate changes live without a deployment.
Entitlements, RBAC, parent-child accounts, contract versioning, and ramped contracts all sit in the AGPL-3.0 build.
Multi-currency across Stripe, Razorpay, Moyasar, and Nomod.
"If billing doesn't work, we don't make money. Flexprice lets us focus on the core business instead of building billing as a second product." - Shubhendu Shishir, Head of Engineering, Simplismart.
The plan ladder runs free to 100K events a month, $500 to 1M, $1,000 to 5M, and custom above, with 20% off yearly. Self-hosting is free and we never take a percentage of revenue.
AI Billing Is Not Easy, But Flexprice Can Make it Easy
AI Billing Is Not Easy, But Flexprice Can Make it Easy
2. Orb
Orb does simple self-serve pricing well, with hosted rollups above 500,000 events per second and dimensional pricing without limit. Complexity is the ceiling: as pricing and go-to-market motions grow, Orb stops keeping up. Closed source under Adyen since 1 July 2026, quote-only with no free tier and no entitlement primitive in its docs.
3. Metronome
Metronome does high-volume metering well, designed as a metering point solution for engineers rather than a billing platform. Scope is the gap:
Metronome: a metering engine for developers.
Flexprice: end-to-end billing and pricing infrastructure for growth, covering metering, billing, invoicing, reporting, and pricing experimentation.
Closed source and vendor-hosted, inside Stripe since January 2026.
4. Lago
Lago is also open source and self-hostable, publishing 1 to 3 million events per second on Kafka and ClickHouse, so throughput isn't the separator. The difference is reach: Flexprice deploys across any VPC and any geography with every feature in the OSS tier, while Lago's Premium gates entitlements, prepaid credits, the customer portal, RBAC, and minimum commitments.
5. Stripe Billing
Payments and subscriptions are what Stripe Billing was built around, so usage-based products pair it with a separate metering vendor. Flexprice is that metering and billing layer itself, tied to no gateway. Stripe marks prepaid credits with drawdown, commitments, ramp schedules, dimensional pricing, and real-time usage visibility as unsupported.
How do the platforms compare on metering, rating, and invoicing?
Row by row across the billing stack, from each vendor's public docs.
Capability | Flexprice | Orb | Metronome | Lago | Stripe Billing |
|---|---|---|---|---|---|
Metering and rating | |||||
Peak ingestion | Up to 1M events/sec | 500K+/sec | Real-time | 1 to 3M/sec | 100M events/mo |
Aggregation functions | 8, incl. weighted-sum | Supported | Supported | Supported | Sum and count |
Dimensional pricing | Native | Unlimited dimensions | Supported | Supported | Unsupported |
Rate change without deploy | Native | Supported | Undocumented | Supported | Limited |
Billing scope | |||||
Invoicing engine | Native | Native | Metering scope | Native | Subscription-first |
Entitlements | OSS tier | Undocumented | Undocumented | Premium | Not native |
Prepaid credits and wallets | Scale plan | Prepaid and postpaid | Undocumented | Premium | 100-grant cap |
Commitments and ramps | OSS tier | Supported | Supported | Premium | Unsupported |
Parent-child accounts | OSS tier | Undocumented | Undocumented | Org-level entities | No |
Pricing experimentation | Scale plan | Undocumented | Metering scope | Undocumented | No |
Platform and cost | |||||
Source available | AGPL-3.0, all features | Closed | Closed | AGPL-3.0, Premium gates | Closed |
Self-host or on-prem | Any VPC or geography | Enterprise tier | No | Yes | No |
Payment gateways | Stripe, Razorpay, Moyasar, Nomod | Multiple | Multiple | Multiple | Stripe only |
Owner | Independent | Adyen | Stripe | Independent | Stripe |
Cost model | Flat, no revenue share | Quote only, no free tier | Quote only | Flat or free self-hosted | 0.7% of volume |
The bottom block decides more evaluations than the top one. Throughput stopped separating these vendors; ownership and cost structure didn't.
Frequently asked questions
Which usage-based billing platforms are open source?
Flexprice and Lago. Flexprice ships every feature in its AGPL-3.0 tier, including the customer portal, RBAC, and entitlements, while Lago gates several of those behind Premium. Orb, Metronome, and Stripe Billing are closed source.
What do metered billing platforms cost?
Flexprice is flat: free at 100K events, $500 at 1M, $1,000 at 5M monthly. Stripe Billing charges 0.7% of billing volume, Chargebee's Billing plan 0.80% of monthly billing value, and Orb publishes no price at all.
Price one month of your real event volume against each fee structure before shortlisting, and check how to choose a billing platform for the rest. Ingestion and rating are documented at docs.flexprice.io.
2. Orb
Orb does simple self-serve pricing well, with hosted rollups above 500,000 events per second and dimensional pricing without limit. Complexity is the ceiling: as pricing and go-to-market motions grow, Orb stops keeping up. Closed source under Adyen since 1 July 2026, quote-only with no free tier and no entitlement primitive in its docs.
3. Metronome
Metronome does high-volume metering well, designed as a metering point solution for engineers rather than a billing platform. Scope is the gap:
Metronome: a metering engine for developers.
Flexprice: end-to-end billing and pricing infrastructure for growth, covering metering, billing, invoicing, reporting, and pricing experimentation.
Closed source and vendor-hosted, inside Stripe since January 2026.
4. Lago
Lago is also open source and self-hostable, publishing 1 to 3 million events per second on Kafka and ClickHouse, so throughput isn't the separator. The difference is reach: Flexprice deploys across any VPC and any geography with every feature in the OSS tier, while Lago's Premium gates entitlements, prepaid credits, the customer portal, RBAC, and minimum commitments.
5. Stripe Billing
Payments and subscriptions are what Stripe Billing was built around, so usage-based products pair it with a separate metering vendor. Flexprice is that metering and billing layer itself, tied to no gateway. Stripe marks prepaid credits with drawdown, commitments, ramp schedules, dimensional pricing, and real-time usage visibility as unsupported.
How do the platforms compare on metering, rating, and invoicing?
Row by row across the billing stack, from each vendor's public docs.
Capability | Flexprice | Orb | Metronome | Lago | Stripe Billing |
|---|---|---|---|---|---|
Metering and rating | |||||
Peak ingestion | Up to 1M events/sec | 500K+/sec | Real-time | 1 to 3M/sec | 100M events/mo |
Aggregation functions | 8, incl. weighted-sum | Supported | Supported | Supported | Sum and count |
Dimensional pricing | Native | Unlimited dimensions | Supported | Supported | Unsupported |
Rate change without deploy | Native | Supported | Undocumented | Supported | Limited |
Billing scope | |||||
Invoicing engine | Native | Native | Metering scope | Native | Subscription-first |
Entitlements | OSS tier | Undocumented | Undocumented | Premium | Not native |
Prepaid credits and wallets | Scale plan | Prepaid and postpaid | Undocumented | Premium | 100-grant cap |
Commitments and ramps | OSS tier | Supported | Supported | Premium | Unsupported |
Parent-child accounts | OSS tier | Undocumented | Undocumented | Org-level entities | No |
Pricing experimentation | Scale plan | Undocumented | Metering scope | Undocumented | No |
Platform and cost | |||||
Source available | AGPL-3.0, all features | Closed | Closed | AGPL-3.0, Premium gates | Closed |
Self-host or on-prem | Any VPC or geography | Enterprise tier | No | Yes | No |
Payment gateways | Stripe, Razorpay, Moyasar, Nomod | Multiple | Multiple | Multiple | Stripe only |
Owner | Independent | Adyen | Stripe | Independent | Stripe |
Cost model | Flat, no revenue share | Quote only, no free tier | Quote only | Flat or free self-hosted | 0.7% of volume |
The bottom block decides more evaluations than the top one. Throughput stopped separating these vendors; ownership and cost structure didn't.
Frequently asked questions
Which usage-based billing platforms are open source?
Flexprice and Lago. Flexprice ships every feature in its AGPL-3.0 tier, including the customer portal, RBAC, and entitlements, while Lago gates several of those behind Premium. Orb, Metronome, and Stripe Billing are closed source.
What do metered billing platforms cost?
Flexprice is flat: free at 100K events, $500 at 1M, $1,000 at 5M monthly. Stripe Billing charges 0.7% of billing volume, Chargebee's Billing plan 0.80% of monthly billing value, and Orb publishes no price at all.
Price one month of your real event volume against each fee structure before shortlisting, and check how to choose a billing platform for the rest. Ingestion and rating are documented at docs.flexprice.io.
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