Lago

Lago is an open-source billing platform for teams that need to charge for subscriptions, usage, prepaid credits, or a mix of models. It is strongest for developers building flexible billing into a product, particularly AI services that need separate token metering. The trade-off is that Premium pricing is custom, and some capabilities are subject to add-ons or caps.

Overview

Lago connects product usage and commercial terms to customer invoices. It supports recurring invoices, online payments, payment reminders, multi-currency invoicing, and a client portal alongside subscription, usage-based, prepaid, and hybrid pricing. That breadth suits businesses whose customer bills need to reflect both a recurring commitment and activity that varies over time; it is more machinery than a business with only a straightforward fixed subscription may need.

Quotes and order forms can define commercial terms, while entitlements and quotas help set boundaries on what customers can use. Prepaid credits and itemized invoices round out the billing workflow, making it possible to account for consumption while showing how charges add up.

Key features

Usage metering and integrations

Lago can meter AI input, output, and cached tokens separately and attribute them to customers for billing. That is a useful distinction for AI products whose token categories have different billing treatment, rather than treating all usage as one undifferentiated quantity. Listed AI connections include OpenAI, Anthropic, AWS Bedrock, Google Gemini, Mistral, Ramp Router, Snowflake Cortex, Databricks AI Gateway, and Cloudflare AI Gateway.

For developers, the REST API, official JavaScript, Python, Ruby, and Go SDKs, and signed webhooks provide several ways to connect applications and exchange events. Payment and finance integrations include Adyen, GoCardless, Stripe, NetSuite, Xero, Anrok, Avalara, HubSpot, and Salesforce. This range can fit a billing system into a wider product and finance stack, though teams still need to connect usage and commercial rules to the invoices they want to produce.

Deployment and controls

The open-source edition is self-hosted under AGPLv3. Premium can be deployed in the cloud or self-hosted, and Lago says it can run on-premises or in a VPC. Lago states that it is SOC 2 Type II certified and undergoes regular third-party penetration tests; it also describes single sign-on, role-based access controls, and audit logs. Those controls and deployment choices are relevant to organizations with security and infrastructure requirements, but Premium costs and some feature limits need to be settled with Lago.

Pricing

Open source: free. It is AGPLv3-licensed and self-hosted, so it suits teams prepared to run billing on their own infrastructure. This is the no-cost route, but the plan information does not establish Premium support or cloud deployment as part of it.

Lago Premium: custom pricing, with cloud or self-hosted deployment and pricing provided after contacting Lago. Premium includes platform support, business-hours incident management, and implementation guidance. 24x7 incident management and an assigned solution engineer are on-demand add-ons. Some features are add-ons or subject to caps, including billing entities and data pipeline volume, so organizations should clarify their expected use and required capabilities when evaluating the plan.

For readers comparing entry costs, the free self-hosted edition avoids a subscription price but requires the team to operate its own deployment. Premium offers deployment choice and support, but its price and applicable caps are not a simple published basis for budgeting.

Platforms

Lago supports API and web access, as well as self-hosted deployment. The open-source plan is self-hosted; Premium is offered in cloud or self-hosted form.

Who it's for

Lago is aimed at engineering, product, finance, and operations teams, including fast-growing AI companies and global enterprises. It is a good fit when billing needs to combine subscription terms with metered consumption, prepaid balances, quotas, or multiple currencies, and when developers can integrate usage data through an API, SDK, or webhook. Smaller teams seeking a simple hosted subscription tool may prefer a less involved billing setup; teams needing Premium should also be comfortable discussing custom pricing and possible caps before committing.

Pros and cons

• Pros: Covers subscription, usage-based, prepaid, and hybrid billing, giving teams room to combine charging models.
• Pros: Separate metering for AI input, output, and cached tokens can make token consumption attributable and billable by category.
• Pros: Open-source self-hosting costs nothing, and Premium adds a cloud option as well as support and implementation guidance.
• Cons: The free edition is self-hosted, which means teams need to operate their own infrastructure.
• Cons: Premium has custom pricing, while billing entities and data pipeline volume can be subject to add-ons or caps, complicating cost and capacity planning.

Alternatives

For a self-hosted subscription billing alternative, Kill Bill offers a free open-source core and full control of infrastructure and data; its listed platforms also include Linux, macOS, and Windows.

Pabbly Subscriptions may suit a smaller customer base that fits its free plan, which is limited to 50 customers and excludes team members and the affiliate module. Its Standard plan is $14 a month, billed monthly.

PayWhirl offers a free Starter plan with a 3.0% per-transaction fee, in addition to payment gateway processing fees, making its stated transaction cost an important point for readers comparing free entry plans.

UniBee has a free, self-hosted open-source plan with manual setup and community support; it may fit teams willing to handle that setup.

Fakturia is a web-based alternative with a FLEX one plan charging 1.9% of monthly net revenue, no monthly base fee, and including unlimited customer contracts, 7,500 API calls per month, and three users.

Flexprice offers a free plan with 100k events per month and up to $100K in cumulative billing revenue, alongside subscription, usage-based, and hybrid pricing, tax management, billing webhooks, and PDF invoices.

Zuora CPQ has custom pricing based on products, scope, transaction volume, business model, regions, and implementation needs.

Aria Billing is another paid API and web billing option.

Verdict

Choose Lago if your product needs flexible billing for subscriptions and metered consumption, especially if AI token categories need separate customer-level attribution and your team can work through the developer integrations. Its free self-hosted edition provides a no-cost way to run the open-source platform, while Premium adds cloud deployment and support. Look elsewhere if you need predictable published Premium pricing, or if self-hosting and the possibility of caps or add-ons do not fit your operational or budgeting needs.