Game Engine License Agreements: What Unreal, Unity, and Godot Terms Mean for Your Studio

When Unity announced its Runtime Fee in September 2023 — a per-install charge that would have applied retroactively to already-shipped games — the backlash was immediate and existential. Studios that had spent years building on Unity faced the prospect of unpredictable, unbounded costs on games already in the market. Innersloth, Aggro Crab, and Red Hook Studios all publicly condemned the move. Some developers threatened to migrate to Unreal or Godot. Unity reversed the fee in September 2024, but the damage to developer trust was done. The crisis proved something we had been telling studios for years: your game engine license agreement is not just a technical decision — it is a legal risk decision that affects your IP ownership, your revenue model, and your ability to negotiate with publishers.

For game studios, the engine EULA governs three things that matter more than rendering pipelines or physics performance: who owns the modifications you make to the engine, how much of your revenue the engine provider can claim, and what happens to your shipped game if the provider changes terms mid-development. We walk studios through these questions regularly — alongside the COPPA compliance issues and IP ownership questions that arise when games incorporate user-generated or AI-assisted content. This guide breaks down the three dominant engine licenses clause by clause so your studio can make an informed decision before committing years of development time.

The Three Dominant Engines at a Glance

The three engines that dominate indie and mid-market game development — Unreal Engine 5, Unity, and Godot — operate under fundamentally different licensing models. Unreal uses a royalty-based model: free to use, with a 5% royalty on gross revenue after the first $1 million. Unity uses a per-seat subscription model: tiered pricing based on revenue, with no runtime fee (after the 2024 reversal). Godot uses the MIT license: fully permissive, no royalties, no subscription, no revenue thresholds.

Each model creates different legal exposures. A royalty model ties your cost to your success — predictable as a percentage, but potentially large in absolute terms. A subscription model ties your cost to your team size — predictable per seat, but with the risk that the provider can change pricing tiers (as Unity demonstrated). A permissive open-source model eliminates provider-driven cost risk entirely, but shifts support and maintenance burden to your team. The GDC 2024 State of the Game Industry survey found that game engine pricing changes were among the top concerns for developers, reflecting the anxiety Unity's crisis created across the industry.

Unreal Engine 5: The Royalty Model

IP Ownership of Your Game and Engine Modifications

Under the Unreal Engine EULA, the IP split is clear: you own your game, Epic owns the engine. The EULA states that "you own all rights, other than rights in the Licensed Technology, in the Products you develop," and Epic "owns all title, ownership rights, and intellectual property rights in the Licensed Technology." Your game — its assets, code, design, and content — is yours. The engine itself, including any modifications you make to its source code, remains Epic's property under license.

This means you cannot fork Unreal Engine, rebrand it, or incorporate its source code into a competing engine. You can modify the engine for your own project, but those modifications are licensed back to Epic under the EULA terms. The practical implication: if you build a custom rendering pipeline on top of Unreal's source code, you own your game but you do not own the rendering pipeline itself — it remains subject to Epic's license terms and royalty obligations.

Revenue Sharing and Royalty Triggers

Unreal's royalty model is straightforward: you pay Epic 5% of gross revenue after the first $1 million in lifetime gross revenue per product. Gross revenue is calculated before taxes, returns, and platform fees — meaning the 5% applies to the top line, not your net. However, revenue earned through the Epic Games Store does not count toward the first $1 million, and Epic waives its 12% store fee for the first six months of exclusivity, effectively reducing your total engine-plus-store cost.

As of January 2025, Epic introduced the "Launch Everywhere with Epic" program, which reduces the royalty rate from 5% to 3.5% for games launched on the Epic Games Store simultaneously with other platforms (initially Windows, macOS, and Android). This is an incentive, not a requirement — studios that do not launch on EGS still pay the standard 5%. The royalty is self-reported quarterly, and Epic retains audit rights to verify your reporting.

Publishing Restrictions

The Unreal EULA does not restrict where you publish your game. You can ship on Steam, the App Store, Google Play, consoles, or any other platform without Epic's consent. The royalty obligation follows the revenue regardless of platform. This is a significant advantage for studios that want maximum distribution flexibility — there is no exclusivity lock-in unless you voluntarily opt into the Epic Games Store incentive programs.

Unity: From Per-Seat Subscription to Runtime Fee and Back

The 2023 Runtime Fee Crisis

In September 2023, Unity announced a Runtime Fee that would charge developers per install of their game once certain thresholds were met — $200,000 in revenue or 200,000 installs for Unity Personal users, and $1 million in annual revenue plus 1 million lifetime installs for Unity Pro and Enterprise users. The proposed per-install charges ranged from $0.125 to $0.20. The fee would have applied retroactively to already-released games, creating immediate financial exposure for studios with large existing install bases — especially free-to-play titles with high install counts but lower per-user revenue.

The backlash was severe. Developers pointed out that the per-install model was unworkable: Unity could not reliably track installs, the fee would penalize games with legitimate reinstall patterns (users switching devices, redownloading after clearing storage), and the retroactive application violated the implicit bargain studios had made when choosing Unity. Multiple studios announced plans to migrate away from Unity entirely.

The 2024 Reversal and Current Terms

In September 2024, Unity's new CEO Matt Bromberg announced the complete cancellation of the Runtime Fee. Unity reverted to a subscription-based model with the following changes effective January 1, 2025:

• Unity Personal remains free, with the revenue ceiling raised from $100,000 to $200,000. The "Made with Unity" splash screen is now optional in Unity 6.
• Unity Pro costs $2,200 per seat annually (an 8% increase from the previous $2,040). Required once you exceed the $200,000 revenue ceiling.
• Unity Enterprise saw a 25% price increase. Required for studios with more than $25 million in total annual revenue and funding.

Unity also committed to implementing pricing changes only once per year, rather than making mid-year announcements as it did with the Runtime Fee. But the commitment is a policy, not a contractual guarantee — and studios that lived through the 2023 crisis have reason to be cautious about relying on it.

IP Ownership Under Unity's Terms

Unity's terms grant developers ownership of the games they create. Unlike Unreal's EULA, which explicitly addresses engine modifications, Unity's licensing model is built around access to the engine rather than source code rights. Unity Pro and Enterprise users get access to source code under a separate source code license, but modifications to that source code are subject to Unity's restrictions — you cannot redistribute the modified engine or use it outside the scope of your Unity license.

What Happens If Unity Changes Terms Again

The Runtime Fee crisis exposed a fundamental risk of the subscription model: the provider can change pricing terms, and your studio has limited recourse. If you have spent three years building a game in Unity and the company announces a new pricing model, your options are to accept the new terms, abandon the project, or rewrite the game in another engine — a cost that can range from months to years of additional development time. This is the definition of vendor lock-in, and it is the legal risk that the Runtime Fee crisis made visible to the entire industry.

Godot: The MIT Permissive Alternative

Full IP Ownership, No Revenue Sharing

Godot is released under the MIT license, one of the most permissive open-source licenses in existence. Under the MIT license, you are free to use Godot for any purpose — including commercial use — modify the engine, distribute modified versions under a different license (including proprietary), and sell your game with no royalty or revenue-sharing obligation to the Godot Foundation or any contributor. The only requirement is that you include the copyright notice and license statement in your game's documentation or credits.

Crucially, the Godot license explicitly states that "Godot Engine's license terms and copyright do not apply to the content you create with it; you are free to license your games how you see best fit, and will be their sole copyright owner(s)." This means your game, its assets, and even modifications you make to the engine are yours — no royalty, no audit rights, no provider who can change the terms.

The Trade-Offs

The trade-off is support and ecosystem. Godot does not have the same level of third-party asset store, console porting support, or AAA-grade tooling that Unreal and Unity offer. Console publishing on Godot often requires third-party porting companies because the engine does not include native console export (due to NDA-gated console SDKs). For studios targeting PC and mobile, these limitations may be acceptable. For studios planning multi-platform console releases, the cost of third-party porting may offset the licensing savings.

Engine Switching Costs and Lock-In Risk

Switching engines mid-development is rarely feasible. Your codebase, asset pipelines, physics systems, and tooling are all built around a specific engine's architecture. Moving from Unity to Unreal or Godot typically means rewriting the game from scratch — not just the rendering layer, but the entire game logic, input handling, serialization, and networking stack. The cost can range from six months to two years of additional development time, depending on project complexity.

This is why engine choice is a legal risk decision, not just a technical one. If your engine provider can unilaterally change pricing terms — as Unity did in 2023 — your studio's financial model can be disrupted overnight. Studios should evaluate engine EULAs with the same rigor they apply to distribution agreements or publisher contracts: read the termination clause, the change-of-terms provision, and the audit rights before committing.

Under the Unreal EULA, Epic can terminate your license for breach, but the royalty terms are structured as a percentage of revenue — meaning Epic's incentive is aligned with your success. Under Unity's subscription model, the provider's revenue comes from per-seat licensing fees, not from your game's success — meaning the provider's incentive is to maximize subscription revenue, which can lead to pricing decisions that are not aligned with developer interests, as the Runtime Fee crisis demonstrated. Under Godot's MIT license, there is no provider who can change the terms at all.

How Engine Choice Affects Publisher Deal Negotiations

Publishers are increasingly aware of engine licensing risk. A publisher evaluating a game built on Unity in late 2023 would have had to assess the Runtime Fee's impact on the game's revenue projections. Even after the reversal, publishers may ask studios to represent and warrant that their engine license terms will not change materially during the development and publishing period — a representation studios cannot honestly make for proprietary engines with unilateral change-of-terms provisions.

Unreal's royalty model creates a different publisher dynamic. The 5% royalty (or 3.5% with the Epic Games Store incentive) is a known, calculable cost that can be built into the deal economics from the start. Publishers can model the royalty as a line item, just as they model platform fees and distribution cuts. This predictability is an advantage in negotiations — there are no surprise fees that could erode the publisher's return.

Godot's MIT license gives studios the strongest negotiating position. With no royalty, no subscription, and no provider who can change terms, a Godot-built game represents zero engine licensing risk to a publisher. The trade-off — reduced ecosystem support — is a technical risk the publisher can evaluate, rather than a legal risk they cannot control.

Actionable Next Steps

1. Read the EULA before you choose an engine. Do not wait until you are deep in development to discover that your engine provider can change pricing terms unilaterally. Read the EULA's termination clause, change-of-terms provision, and audit rights. Understand whether the provider can modify the agreement mid-project and what your recourse would be.
2. Model the royalty or subscription cost over your projected revenue. For Unreal, model the 5% royalty (or 3.5% with EGS) against your gross revenue projections. For Unity, model the per-seat subscription cost across your team size and project timeline. For Godot, model the cost of any third-party porting or support you may need. Compare total cost across the projected life of the game, not just the development period.
3. Evaluate IP ownership of engine modifications. If your game relies on custom engine modifications — custom rendering, physics, or tooling — understand who owns those modifications under the EULA. Unreal's EULA grants Epic ownership of the Licensed Technology including modifications. Unity's source code license restricts how you can use modified source. Godot's MIT license lets you own and even relicense your modifications.
4. Assess switching costs honestly. If your engine provider changed terms tomorrow, could you switch? What would the rewrite cost in time and money? If the answer is "prohibitive," you have lock-in risk — and you should negotiate contractual protections (price locks, change-of-terms notice periods) before committing, or choose an engine with less lock-in risk.
5. Factor engine licensing into publisher negotiations. Disclose your engine choice and its licensing terms to potential publishers early. If your engine carries pricing-change risk (Unity post-2023), be prepared to address it. If your engine has predictable costs (Unreal royalty) or no provider risk (Godot), use that as a negotiating advantage.
6. Have a contingency plan. Even if you never use it, having a documented plan for what you would do if your engine provider changed terms — including the cost and timeline of switching — gives your studio a rational response to a crisis rather than a panic-driven decision. The studios that survived the Unity Runtime Fee crisis best were the ones that had already evaluated their alternatives.
7. Talk to a lawyer before you commit. The cost of an engine EULA review before you start development is a fraction of the cost of discovering, three years in, that your license terms have changed or that you do not own what you thought you owned. We help game studios evaluate engine licenses, negotiate terms where possible, and build contingency plans for provider-driven risk.

Engine choice is one of the earliest and most consequential decisions a studio makes. It determines your cost structure, your IP position, and your vulnerability to provider-driven changes for the entire life of your game — and potentially for future titles built on the same technology stack. The studios that treat engine licensing as a legal risk decision, not just a technical preference, are the ones that can ship with confidence. The studios that sign whatever EULA ships with the download are the ones that discover, at the worst possible moment, that they gave away more than they intended.