# How Estella Is Licensed and Funded This is a public, plain-language statement of Estella's licensing and business model. We want there to be **zero ambiguity** about what you can do with Estella and how the project pays for itself. ## TL;DR - **Estella is licensed under [Apache-2.0](LICENSE).** Use it for anything, including commercial games and commercial products, free of charge. No royalties, no seat fees, no revenue thresholds, no "free for indies, paid for studios" tier. - **The whole engine is open and stays open.** The engine runtime, the SDK, the editor, the build CLI, and the runtime loader are all Apache-2.0. We do not hold core features back behind a paywall. - **We fund the project from things built _around_ the engine, not from the engine itself** — sponsorship, optional hosted/"pro" add-ons, a marketplace, and paid support. Every one of those is optional; none of them gate the open-source engine. - **One caveat that is not ours to waive:** the bundled **Spine Runtimes are not open source**. If you ship a game using Estella's Spine integration, you need a Spine license from Esoteric Software. See [NOTICE](NOTICE). ## Why Apache-2.0, and why we reverted the noncommercial experiment For a short window (v0.13.0, June 2026) Estella shipped under the PolyForm Noncommercial License, with a separate paid commercial license. We reverted that in v0.14.0. The honest reasons: - A noncommercial-only engine can't be adopted by the people who would actually build on it — studios, freelancers, and anyone shipping a paid game. Adoption is the foundation everything else here depends on. - "Free for noncommercial, pay us for commercial" creates friction and uncertainty exactly when a developer is deciding whether to commit. That uncertainty is more expensive to the project than the license revenue it might have produced. - We'd rather compete on being genuinely good and genuinely open than on license enforcement. We chose **Apache-2.0** (over MIT) because it adds an explicit **patent grant** and a clear **trademark** boundary, which protect both users and the project, while still being fully permissive and commercial-friendly. It is also compatible with the permissive licenses of our bundled dependencies. ### Our promise (no rug-pull) The Apache-2.0 grant is **irrevocable** for the code released under it. We can't take back the rights you already have, and we don't intend to. The core engine will remain under a permissive OSI-approved license. If governance ever moves (for example, to a foundation), it will only move in a direction that keeps the engine open. ## What is always free and open Everything needed to build and ship a game is Apache-2.0 and lives in this repo: - the C++/WebAssembly engine runtime and renderer, - the TypeScript SDK (`esengine`) and the web loader (`@esengine/web-loader`), - the visual editor, - the build/CLI tooling, - documentation and examples. We will not move a feature from this list behind a paywall. New core capabilities land here, openly. ## How the project is funded Four pillars, all built _alongside_ the open engine rather than by restricting it: ### 1. Sponsorship & donations Recurring sponsorship (e.g. GitHub Sponsors / OpenCollective) and one-off donations from individuals and companies that depend on Estella. Sponsors may get recognition and a louder voice on the roadmap — never exclusive access to core features. ### 2. Optional hosted & "pro" add-ons (open-core, done honestly) Convenience products that sit on top of the open engine and are worth paying for because they save time, not because the engine was crippled without them — for example a hosted/cloud editor, team collaboration, a managed build-and-publish pipeline, or a pro asset pipeline. These are **separate products**: the open-source engine is fully usable, self-hostable, and shippable without any of them. ### 3. Marketplace A place to buy and sell assets, templates, and plugins, with the project taking a small cut. The engine and the ability to load third-party content stay free; the marketplace is an optional storefront. ### 4. Support, training & consulting Paid priority support, training, and custom development for studios that want a direct line or specific work done. The community gets best-effort support for free via Discord/issues/QQ. ## Boundaries we hold ourselves to - The **core engine stays Apache-2.0** and stays feature-complete on its own. - Paid offerings are **additive and optional** — they never remove or gate functionality that is in the open-source engine today. - We won't make the open build deliberately worse to push the paid one. - **Trademarks:** Apache-2.0 covers the code, not the "Estella"/"ESEngine" names and logos. Please say your project "uses Estella," but don't ship a fork under the Estella name or imply official endorsement. - **Attribution:** if you redistribute Estella (including inside a closed-source product, which Apache-2.0 allows), keep the LICENSE and NOTICE and mark changed files — see [NOTICE](NOTICE) and Apache-2.0 §4. ## Status These funding pillars describe the direction, not a finished storefront — most are not live yet. What **is** committed today is the licensing: Apache-2.0, free for commercial use, no rug-pull. As paid offerings come online they'll be announced here and in the [CHANGELOG](CHANGELOG.md). ## Contact Questions about licensing, sponsorship, or commercial support: **359807859@qq.com** · [Discord](https://discord.gg/sAX6PXZ9) · QQ Group 481923584.