The Yarn Spinner Public License

The Yarn Spinner Public License (YSPL) is a new license developed by us for trial in some of our new product releases. It shares many of the same permissive, free, open source conditions as the MIT License our existing tools are licensed under, but with two key areas of difference:

On this page, you can find answers to key questions:

Yarn Spinner Public Licence (YSPL) - Version 1.0

Copyright © Yarn Spinner Pty. Ltd. All rights reserved.

This summary is provided for convenience only and has no legal effect. The binding terms are set out below. In the event of any conflict between this summary and the operative terms, the operative terms prevail.

Yarn Spinner is free to use for most people and most projects.

We would love to hear about what you are making! This is not a condition of the Licence, but if you would like to share your project with us or have any questions about this license or our software, please reach out to us at https://yarnspinner.dev or on social media.

If your project has the budget to do so, please consider purchasing a commercial licence. It is not required under this Licence, but it helps us keep developing and supporting Yarn Spinner for everyone.

That's it. Now go make something amazing.

"Software" means the specific Yarn Spinner software, including all source code, object code, documentation, and associated files made available under this Licence.

"Licence" means the Yarn Spinner Public Licence as set out in this document.

"Licensor" means Yarn Spinner Pty. Ltd., a company registered in Tasmania, Australia.

"You" (or "Your" ) means the individual or Legal Entity exercising permissions granted by this Licence.

"Legal Entity" means the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty per cent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity.

"Contractor" means any third party, including any contractor, freelancer, or porting service provider, engaged by You to perform work on Your Licensed Product on Your behalf.

"Competing Product" means a software tool, plugin, asset pack, library, framework, or service whose primary purpose is enabling third parties to create one or more of the following:

(a) branching dialogue or conversation systems; (b) non-linear or interactive narrative systems; (c) narrative scripting tools or editors; (d) dialogue tree or conversation editors; (e) interactive fiction, visual novel, or text adventure authoring tools; (f) a compiler, runtime, or interpreter for the Yarn language or any substantially similar language.

The following are not Competing Products:

"Licensed Product" means any game, application, or other end-user product that incorporates the Software as an embedded component, together with substantial original content, and whose primary purpose is not the redistribution or resale of the Software itself.

Subject to the terms and conditions of this Licence, the Licensor hereby grants You a worldwide, royalty-free, non-exclusive, non-transferable licence to use, copy, modify, and distribute the Software, subject to the conditions and limitations set out below.

The rights granted in Section 2 are subject to and conditional upon compliance with all of the following conditions. Failure to comply with any condition automatically terminates the rights granted under this Licence, as set out in Section 9.

(a) You must retain the copyright notice set out at the top of this Licence and include a copy of this Licence in all copies or substantial portions of the Software.

(b) You must credit Yarn Spinner in a location visible to end users of Your Licensed Product. Acceptable locations include, but are not limited to:

The credit must be placed alongside acknowledgements for other tools and middleware used in the project (such as game engines, sound engines, and similar), where such acknowledgements exist.

(a) You may not use the Software, in whole or in part, to create, develop, distribute, or offer a Competing Product, as defined in Section 1.

(b) For the avoidance of doubt, the following uses are expressly permitted and do not breach this condition, provided they do not constitute or form part of a Competing Product:

(a) The rights granted in Section 2 do not include, and You are expressly prohibited from, using the Software, its documentation, or any associated materials to:

(b) For the avoidance of doubt, the following uses are expressly permitted and do not breach this condition:

(c) Where You use AI-powered tools as permitted under Section 3.3(b), You must take reasonable steps to ensure that such tools do not transmit the Software's source code, documentation, or any substantial portion thereof to any remote server, service, or third party for the purpose of training, fine-tuning, or improving any AI system, machine learning model, or large language model. Reasonable steps include, where available, disabling telemetry, opting out of training data collection, or selecting tool configurations that do not transmit source code for training purposes. For the avoidance of doubt, this condition does not apply to the transmission of Your own original Yarn scripts or Your own original code that calls the Software's public API.

(a) In a Licensed Product. You may distribute the Software in compiled or object-code form as an embedded component of a Licensed Product, including for commercial purposes.

(b) To Your team. You may share the Software (including modified versions) in source-code form with members of Your own Legal Entity or with Contractors working on Your Licensed Product, provided each such person is bound by terms no less restrictive than this Licence.

(c) Public forks. You may publish or otherwise make publicly available a modified version of the Software in source-code form, provided that all of the following conditions are met:

(i) the modified version is distributed solely under this Licence, with no additional or different terms;

(ii) the modified version is made available free of charge and is not sold, sublicensed, or offered as a paid product or service, whether directly or indirectly (including, without limitation, through subscription fees, support contracts bundled with access, or paywalled repositories);

(iii) the modifications were made primarily to address Your own requirements in connection with Your own use of the Software (such as bug fixes, performance improvements, platform adaptations, engine compatibility updates, or localisation support) and the modified version is not actively marketed, branded, or promoted as an alternative to or replacement for the Software; and

(iv) the modified version complies with Section 6.

(d) No standalone distribution. You may not distribute, sell, sublicense, lease, lend, or otherwise make available the unmodified Software as a standalone product, whether in source-code or compiled form. The unmodified Software may only be distributed as an embedded component of a Licensed Product under Section 3.4(a) or shared with Your team under Section 3.4(b).

(e) No other distribution. Except as expressly set out in this Section 3.4, You may not distribute the Software in any form.

(a) You may have a Contractor work on Your Licensed Product on Your behalf, provided that:

(i) the Contractor agrees in writing to be bound by terms no less restrictive than this Licence with respect to the Software;

(ii) the Contractor's use of the Software is solely in connection with work performed for You on Your Licensed Product; and

(iii) You remain responsible for the Contractor's compliance with this Licence.

(b) For the avoidance of doubt, this Section permits console porting houses and similar service providers to access and modify the Software on Your behalf, subject to the conditions above.

(a) You may be subject to additional terms and conditions imposed by third parties in connection with Your use of the Software, including (without limitation) platform holder agreements, console manufacturer NDAs, distribution platform terms, or employer policies ("Additional Terms").

(b) Additional Terms may impose restrictions beyond those set out in this Licence. For example, a console platform holder's NDA may restrict public disclosure of modifications to the Software that incorporate the platform holder's confidential information. Such additional restrictions do not conflict with this Licence.

(c) Additional Terms may not grant rights or permissions that this Licence does not grant. Where Additional Terms purport to permit conduct that this Licence prohibits, this Licence prevails and such conduct remains prohibited.

(d) You are responsible for complying with both this Licence and any applicable Additional Terms. Where the two impose different obligations on the same conduct, You must satisfy both.

You may modify the Software for Your own use, share modified versions with Your team in accordance with Section 3.4(b), and publish modified versions in accordance with Section 3.4(c), provided that:

(a) You include the copyright notice and this Licence in the modified version;

(b) the modified version is not used to create a Competing Product; and

(c) the modified version is not presented in a way that suggests it is the official Yarn Spinner release or is endorsed by the Licensor.

You are not required to share Your modifications with the Licensor or with anyone else. This is not a copyleft licence.

Commercial licences with alternative terms are available from the Licensor. A commercial licence may, for example, modify or remove the attribution, non-competition, or AI training conditions set out above. The availability, terms, and pricing of commercial licences are at the Licensor's discretion. For details, visit https://yarnspinner.dev .

This Licence does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Software and fulfilling the attribution requirements of Section 3.1.

(a) This Licence, and all rights granted under it, terminate automatically and immediately if You fail to comply with any of Your obligations under this Licence.

(b) Upon termination, You must cease all use of the Software and destroy all copies in Your possession or control.

(c) Termination does not affect any rights or remedies available to the Licensor at law or in equity, including (without limitation) the right to seek injunctive relief or damages for breach.

(d) If You cure the breach within thirty (30) days of becoming aware of it, and the Licensor has not notified You of termination, the Licence is reinstated retroactively. If the Licensor has notified You of termination, reinstatement is at the Licensor's sole discretion.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. IN NO EVENT SHALL THE LICENSOR BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

To the extent permitted by the Australian Consumer Law (Schedule 2 of the Competition and Consumer Act 2010 (Cth)), any implied warranties, guarantees, or conditions that cannot be excluded are limited to the maximum extent permitted by law.