Overview

Open-Source Billing Infrastructure You Own and Control

SaaS billing vendors lock you in with per-transaction fees that grow as you scale. Kill Bill is free under the Apache 2.0 license — you can deploy, customize, and extend it without asking permission or paying royalties.

Learn more about open-source software

Accept every major payment
method

Visa

Mastercard

Amex

PayPal

ACH

Integrate with any payment gateway worldwide

Adyen

Braintree

Stripe

PayPal

Support alternative payments
and digital currencies

Cash

SMS

Bitcoin

Boleto

Proven at Scale. Built to Adapt.

Kill Bill is comprised of…

Your dedicated billing engine

Kill Bill powers your back-end, processing customer activities through API calls triggered by your website actions (e.g., purchasing a year's subscription).

You create and implement the API calls that connect with the Kill Bill platform.

Persistent data you control

The database manages all the states associated with the subscriptions, invoices, payments, and so forth.

A back-office dashboard for your team

Kaui is an online user interface that lets your back-office people (for example, Finance or Support) interact with Kill Bill.

Kaui makes it possible for your employees to manage tasks like issuing refunds and adjusting invoices.

Proven at Scale

15+ years in production. Billions in revenue processed.

Kill Bill has been battle-tested in highly regulated environments. Examples include PCI-compliant payment processing and Fortune 500 deployments with complex multi-tenant billing scenarios.

$10M-$250M ARR

Our sweet spot: growth-stage companies scaling billing infrastructure without scaling vendor bills.

Compliance-Ready Architecture

Kill Bill provides the technical controls—RBAC, audit logs, encryption, tokenization—that enterprises need to meet SOC 2 and PCI-DSS requirements. Proven across years of enterprise deployments.

Multi-Tenant at Scale

White-label billing for platforms managing thousands of tenants across B2B, B2C, and B2B2C models.

Implementation

Deploy and manage in your own infrastructure

Or as a software appliance in the cloud

Run billing and payments out of the box

Kill Bill includes all of the basic features a business needs to run subscription billing processes and payment processes. Thousands of organizations use Kill Bill as their basic billing system with payment processing features.

Build custom logic on top

The real power of Kill Bill lies in building your own business logic on top of it to create a customized billing and payments solution. You can write plugins to modify Kill Bill’s behavior or integrate with third-party vendors.

Use open-source plugins or create your own

Kill Bill already has many open-source plugins. You can use them as examples for creating your own or modify them for your own use. For example:

Fraud detection solutions

Tax provider solutions

Credit card account updaters

Customers

Who should use
Kill Bill?

Kill Bill is eminently suitable because it’s affordable and extensible. Most importantly, it is secure and stable.

Online businesses

Here at Kill Bill, we believe that any business that bills its customers and/or accepts payment online can (and should) use Kill Bill as its billing system.

Teams that need full customization

You’re frustrated with the lack of customization available from the more popular SaaS billing-payment providers.

Startups

You’re a startup with a tight budget.

Kill Bill is right for
‍your business if...

Your business requires integration with lesser-known payment gateway providers, such as those used internationally.

Your business needs to use a different fraud detection provider (or account updater or tax provider) than the one used by your payment gateway.

You need to run custom, decision-making code (examples: change amounts dynamically, abort payments with a rules engine due to fraud detection, modify invoices on-the-fly, customer payment retry logic).

You need real-time access to your organization’s data to build analytical and financial report.

You need to integrate with your own internal applications (examples: for tax rates or tight integration with your catalog system).

You guessed it…

If you agree to any of these statements, check out Kill Bill’s open-source billing and payments platform features (not to mention Kaui). You can also read over some typical and not-so-typical Kill Bill use cases.

View Features

View Kaui

Security & Compliance

Enterprise-grade security, by design

Kill Bill is built for organizations that take data sovereignty and regulatory compliance seriously. Self-host in your own infrastructure with full source code transparency.

Self-Hosted Infrastructure

Your billing data never leaves your infrastructure. Deploy on-premises or in your own cloud with complete data sovereignty and network isolation.

Open-Source Auditability

Full source code inspection — no black boxes. Your security team can audit every line of the billing engine before deployment.

PCI-Ready Architecture

Kill Bill provides the technical building blocks for PCI DSS compliance: payment data tokenization, encryption, RBAC, and comprehensive audit trails. Enterprises have relied on these controls for years to meet their compliance goals.

Encryption Support

Kill Bill supports encryption at rest and in transit, with industry-standard TLS for communications and AES-256 for stored data.

Audit Logging

Comprehensive audit trail for every state change. Track who did what, when, with full event history for compliance reporting.

Access Control

Role-based access control with fine-grained permissions. Multi-tenant isolation ensures data separation between business units.