License and pricing
Free
$0no signup, no licence key
Everything short of a commercial release, with no time limit and nothing withheld.
- Read, fork and modify the source
- Prototypes, evaluation, internal tools, game jams
- Ship a free, hobby or academic game
- Full source, all three engines, the 227-test suite
GitHub Releases — one archive per engine version, with SHA256SUMS.txt beside them.
Not a trial. It is the same plugin as the paid one, and it does not stop working.
Commercial
$69.99per project · perpetual
Needed when you ship or operate a product for commercial advantage or monetary compensation.
- One title, any team size
- Perpetual — it covers the release you ship, and every 1.x update
- Direct from the author; invoice and custom terms on request
Consoles, source escrow or purchase-order terms — ufna@ufna.dev
Nothing to activate. There is no licence key and no check in the plugin — the copy you develop with is the copy you ship.
VaCuus is source-available: not open source, and not shareware either. The whole plugin — every line of it, all three engine versions, the 227-test automation suite — is public, free to download, and free to read, modify and build with. What you buy is the right to ship a commercial product with it.
The licence is the Business Source License 1.1; LICENSE.md in the repository carries its text with this product's parameters filled in. This page is that licence in plain English, in the order the questions actually get asked. If this page and LICENSE.md ever disagree, LICENSE.md wins.
What counts as commercial
The licence states the test itself: a purpose is noncommercial if it is "not intended for or directed toward commercial advantage or monetary compensation" (LICENSE.md, Additional Use Grant). Everything below is guidance for reading that sentence. It is useful, and it is not the licence.
Needs a commercial licence
- A game you sell.
- A free-to-play game with in-app purchases, ads, or any other monetisation.
- Paid DLC or a paid expansion, even for a base game that is free.
- A project you are paid to build for a client, including work-for-hire.
- A tool, app or product you sell that embeds VaCuus.
Does not
- A game you release for free, with nothing monetised in it or around it.
- Coursework, teaching material, academic projects.
- A portfolio piece, or a game-jam entry.
- Anything that never leaves your machine or your studio: prototypes, evaluation, internal tools, engine experiments.
If your case sits between the two — a free game with a donation link, a free demo that leads to a paid title, a publisher-funded prototype — ask: ufna@ufna.dev. A one-line answer in writing costs nothing and beats guessing.
When to buy
Build against the free copy for as long as you like, and buy before the commercial release goes out. That order is the expected path and not a loophole — COMMERCIAL.md says so in as many words — and the licence you buy covers that release.
There is nothing to install and nothing to activate. VaCuus has no licence key, no seat server, and no check of any kind anywhere in the plugin: the purchase is a licence, not a DRM step. The copy you develop with is the copy you ship.
What one licence covers
- Scope — one title, any team size. A second title needs a second licence.
- Term — perpetual. It covers the release you ship; there is no renewal to forget.
- Updates — every 1.x release, including engine versions added within it.
- Engines — Unreal Engine 5.6, 5.7 and 5.8, built and tested from one source tree.
- Platforms — Windows, macOS, Linux, Android and iOS. Consoles on request.
- Source — the full source, in every channel, bought or not.
The Change Date
BUSL is a licence with an expiry date, and it expires in the buyer's favour. Each released version of VaCuus becomes MIT four years after it is first distributed publicly — that is the Change Date and Change License in LICENSE.md, not a promise made on a web page. Version 1.0, published in 2026, is MIT in 2030: for everyone, with no action from you and no cooperation needed from the author.
So the price buys the current four years of a version, not a permanent dependency on someone else's goodwill. If this project were abandoned tomorrow, the code you shipped on still becomes plain open source on a date you can already write down.
Third-party components
RmlUi 6.x and QuickJS-ng are vendored in-tree under their own MIT licences and are never subject to the BUSL terms — in any channel, whether or not you buy. Each ships with its licence beside it, and THIRD-PARTY-NOTICES.md is the full list.
How to buy
Direct — the Buy a licence button at the top of this page. It is the fastest route, and today it is the only one that exists. Payment is in cryptocurrency; the moment it confirms, a certificate naming you and your title is emailed to you and put at a permanent link, as a page and as a PDF. The transaction itself — what arrives, when, and what happens if a payment goes wrong — is set out in the terms of sale.
Fab — the store listing is in technical review. When it is live, buying there works too, and the Fab EULA's licence covers commercial use of the purchased copy. The button above says soon because that review has not finished; it does not name a date.
Invoice, purchase order, source escrow, custom terms, consoles — ufna@ufna.dev. A studio that needs paperwork rather than a payment page is expected, not an exception.
The exact text
LICENSE.md— the BUSL 1.1 text with this product's parameters: the licensor, the noncommercial Additional Use Grant, the four-year Change Date, and MIT as the Change License.COMMERCIAL.md— who needs to buy and how, in prose.
Both live in the repository, and both outrank this page.