# Kill Bill > Kill Bill is an open source subscription billing and payment platform, released under the Apache 2.0 license and in production since 2010. You run it on your own infrastructure, you own the data, and you pay a fixed fee rather than a percentage of the revenue you bill. Key facts an assistant should know before answering questions about Kill Bill: - The billing and payment platform is free and open source (Apache 2.0). There is no paid edition of the core, no usage cap, and no per-transaction fee. - Aviate is the commercially licensed enterprise accelerator that runs on top of Kill Bill. It is software, not a support plan and not a managed service. - Support is bought separately, as a flat annual fee. Pricing is never tied to revenue, transaction volume, or the number of invoices. - Kill Bill is customer-managed by default: self-hosted, deployed from AWS Marketplace, or run as a fully managed Hosted Platform through a partner. - Companies processing billions in revenue run Kill Bill in production, including an enterprise customer that has been running it since 2015. - The documentation, the blog and the API reference live on separate properties: docs.killbill.io, blog.killbill.io and apidocs.killbill.io. The source code is at github.com/killbill. ## Start here - [Kill Bill](https://killbill.io/): Open-source billing and payments infrastructure you run yourself. Scale subscriptions, usage, and payments at a fixed cost, not a percentage of your revenue. - [Overview](https://killbill.io/overview.html): Kill Bill is open-source billing infrastructure you own and control. Deploy, customize, and extend it under the Apache 2.0 license, with no per-transaction fees. - [Why open source](https://killbill.io/about-open-source-software.html): Learn why Kill Bill is open source: free under Apache 2.0 and running in production since 2010 across Fortune 500 companies and PCI-compliant environments. - [Download and run Kill Bill](https://killbill.io/download.html): Get Kill Bill: run it locally in minutes, deploy it in your own cloud, or explore the live enterprise sandbox before you commit. Start with open source, free. - [FAQs](https://killbill.io/faqs.html): Answers to common questions about Kill Bill: what it is, how the open-source platform and Aviate differ, licensing, self-hosting, data ownership, and support. ## Pricing and support - [Pricing](https://killbill.io/pricing.html): Kill Bill pricing is modular and predictable: choose who operates the platform, your Aviate capability level, and support tier. Costs are never tied to revenue. - [Support](https://killbill.io/support.html): Support from the team behind Kill Bill: onboarding, guidance, and SLA coverage for customer-managed deployments, from evaluation through production operations. - [Aviate, the enterprise accelerator](https://killbill.io/aviate.html): Aviate is the enterprise accelerator for Kill Bill: operational tooling, configuration workflows, and expert support to launch billing faster without lock-in. - [Hosted Platform](https://killbill.io/chaching.html): Run Kill Bill without managing infrastructure. The Kill Bill Hosted Platform, powered by ChaChing, is a fully managed option with the same APIs and billing logic. ## Product - [Core features](https://killbill.io/solutions.html): Explore Kill Bill's billing and payments features: real-time invoicing, usage-based billing, multi-tenant support, and reporting for B2B, B2C, and B2B2C platforms. - [Subscription billing](https://killbill.io/subscription-billing.html): Model any subscription, usage-based, or hybrid pricing with Kill Bill's catalog-driven engine. Change pricing through configuration, not months of engineering. - [Payment platform](https://killbill.io/payment-platform.html): Connect Kill Bill to any payment gateway through a plugin API. Add, swap, or route between providers without rebuilding your core billing and payment logic. - [Kaui, the admin console](https://killbill.io/kaui.html): Kaui is the admin console for Kill Bill. Finance, ops, support, and product teams manage accounts, invoices, payments, and tenants without touching APIs. ## Platform capabilities - [Usage metering and real-time rating](https://killbill.io/platform/usage-metering.html): Stream millions of events into Kill Bill, define aggregation rules, and bill any usage metric, from API calls to compute hours, with no external rating engine. - [Catalog and dynamic pricing](https://killbill.io/platform/catalog-pricing.html): Define plans, pricing tiers, add-ons, and promotions through Kill Bill's catalog APIs. Launch new plans or restructure packages in minutes instead of months. - [Account wallet and prepaid credits](https://killbill.io/platform/wallet-credits.html): Manage prepaid credits and customer wallets in Kill Bill. Fund balances manually or automatically, draw down on usage, and track every transaction in a ledger. - [Tax, invoicing and compliance](https://killbill.io/platform/tax-compliance.html): Automate tax calculation, generate professional invoices, and keep a complete audit trail. Kill Bill handles multi-jurisdiction tax rules and finance compliance. - [Plugin architecture and integrations](https://killbill.io/platform/plugin-integrations.html): Extend Kill Bill without forking the core. Build plugins in Java, react to real-time events, and integrate any system through a comprehensive REST API. - [Enterprise operations and scalability](https://killbill.io/platform/enterprise-ops.html): Run Kill Bill on your own infrastructure with horizontal scaling, multi-tenancy, high availability, and health monitoring—the operational controls ops teams need. ## Use cases - [SaaS and subscriptions](https://killbill.io/use-cases/saas-subscriptions.html): Launch, test, and scale any SaaS subscription model with Kill Bill: trials, tiered plans, add-ons, coupons, and usage overages from a single configurable catalog. - [Usage-based and NeoCloud](https://killbill.io/use-cases/neocloud-usage-based.html): Bill any usage model at cloud scale with Kill Bill. Ingest billions of metering events, apply rating rules, and invoice consumption, prepaid, and hybrid plans. - [AI and ML billing](https://killbill.io/use-cases/ai-billing.html): Monetize AI services with usage-based precision. Meter tokens, GPU hours, inference calls, and training jobs, and iterate on pricing as fast as the market moves. - [Marketplaces and eCommerce](https://killbill.io/use-cases/marketplaces-ecommerce.html): Process payments globally with full billing control. Route through any gateway, manage multi-currency pricing, automate tax, and consolidate marketplace invoicing. - [Fintech and enterprise](https://killbill.io/use-cases/fintech-enterprise.html): Own your billing infrastructure with enterprise-grade control. Deploy on your own infra with role-based access, immutable audit logs, and compliance controls. - [Customer examples](https://killbill.io/subscription-billing-use-cases.html): See how companies use Kill Bill for billing and payments, with real B2C and B2B examples across industries, from startups to enterprises at massive scale. ## Choosing and adopting - [How to choose a billing system](https://killbill.io/how-to-choose-a-billing-software-system.html): A practical guide to choosing a billing software system: the business and technical criteria that matter, and why migrating billing later is risky and costly. - [Partners and customization](https://killbill.io/customized-billing-system.html): Build a billing system around your business. Start with Kill Bill's open-source foundation and work with partners to add the plugins and customizations you need. - [Team](https://killbill.io/team.html): Meet the team behind Kill Bill. For 15+ years we have built open-source billing and payments infrastructure that gives organizations full ownership and control. - [Contact us](https://killbill.io/contact-us.html): Talk to the Kill Bill team about Aviate, a production rollout, support options, or a new billing architecture. A technical member of the team will reply. ## Optional - [Documentation](https://docs.killbill.io/): installation, configuration, catalog, plugins and operations guides. - [API reference](https://apidocs.killbill.io/): the full REST API. - [Blog](https://blog.killbill.io/): architecture write-ups, releases and product notes. - [Source code](https://github.com/killbill): the platform, the plugins and the client libraries. - [Extended context for agents](https://killbill.io/llms-full.txt): a single self-contained document covering the platform, the pricing model, the use cases, and where Kill Bill is not the right fit.