Kill Bill review

Kill Bill is an open-source billing and payments platform for subscription businesses and companies that charge by usage or use complex payment models. You can self-host the core platform, or choose Aviate, a separate managed option built on it. Those are materially different buying paths, not two prices for the same hosted plan.

The product covers subscription setup, pricing models, trials and usage billing. It also includes usage metering and rating, while plugins connect payment gateways, issuing banks and fraud tools. Kaui is the web interface for administering price books, subscriptions and payments. The feature set also includes prepaid wallet balances and top-ups, plus tax-rule configuration, invoicing and audit capabilities.

Kill Bill is most relevant when billing rules are part of your product and you want control over the stack. It is not simply a hosted checkout subscription: the open-source route means self-hosting, while Aviate is the managed alternative.

Kill Bill’s clearest advantage is pricing flexibility for teams willing to self-host. The pricing page lists the open-source option at $0 per month under an Apache 2.0 license, with no usage limits, per-transaction fee or percentage-of-revenue charge. That is a meaningful contrast with billing platforms that tie costs to transaction volume or revenue.

The feature set is also aimed at more than basic recurring charges. It includes trials, usage metering and rating, prepaid balances, top-ups, and plugins for payment gateways, issuing banks and fraud tools. Kaui gives teams a web interface for managing price books, subscriptions and payments, rather than making every administrative task a code-only workflow.

Aviate keeps two of the same pricing advantages—no per-transaction fee and no percentage of revenue—while providing a managed route. For teams that want to avoid self-hosting, that distinction may matter more than the sticker price. But it is worth weighing carefully: according to the pricing page, Aviate costs $9,999 per month when billed annually.

Aviate is expensive, and its pricing is not fully transparent. The pricing page lists $9,999 per month when billed annually, but does not publish a monthly-billing price. It also does not publish Aviate’s seat or usage limits. A buyer cannot compare the managed plan’s cost per seat or expected usage tier from the published details.

The $0 open-source price is not the same as a $0 operating cost. Self-hosting means your team takes responsibility for running the platform; the published pricing details do not state infrastructure, implementation or support costs. The open-source plan has no usage limits or transaction fees listed, but that does not answer what it will cost to operate at your scale.

The available details also do not specify plan-level support, migration help or technical limits beyond the stated pricing caps. Teams that need those answers should get them in writing before choosing between self-hosting and Aviate.

Kill Bill’s open-source edition is listed at $0 per month, with an Apache 2.0 license, no usage limits, no per-transaction fee and no revenue share. That does not make a self-hosted deployment cost-free: hosting and implementation costs are not published on the vendor's site.

Aviate, the separate managed option, is listed at $9,999 per month when billed annually. That is a jump from $0 to a $9,999 monthly equivalent, with an annual billing commitment; a monthly billing price is not published. Seat and usage limits are also not published, so buyers cannot use the listed price alone to estimate costs as their team or volume grows.

No add-ons are listed in the published pricing details. The no-transaction-fee and no-revenue-share terms apply to both plans, but they do not clarify what hosting, support or other services cost. Get those terms and Aviate’s limits in writing before comparing its total cost with a self-hosted setup.

Treat a move to Kill Bill as a billing-system migration, not just a gateway change. The platform covers subscriptions, pricing, usage metering, payments, wallets, tax and invoicing; the published information does not document a migration service or a standard import path. Before moving, map the records and rules you need to carry over, including subscription state, usage history, balances, invoices and payment integrations. Confirm which can be imported and how they will be validated.

Kill Bill’s open-source edition is Apache 2.0 licensed and can be self-hosted, which gives teams more control over the software than choosing a managed service. But the published material does not document data-export formats, export tooling or how portable Aviate data is. Verify those details before committing, especially if you may leave later.

We were not given Reddit posts or comments for this review, so we can’t attribute reasons for leaving to Reddit users. Support terms are also not documented on the vendor's site. Ask about support, export rights and exit assistance before signing up for Aviate.