License

TrailBase is free and open-source software, licensed under the Open Software License 3.0 (OSL-3.0). Client libraries are dual-licensed under the permissive Apache-2.0 license.

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TL;DR

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License Overview

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Server: OSL-3.0

The TrailBase server is licensed under the Open Software License 3.0 (OSL-3.0), an OSI-approved copyleft license. What this means: ✅ Freely use TrailBase for any purpose (personal, commercial, etc.) ✅ Modify TrailBase and use your modifications ✅ Deploy TrailBase on your infrastructure ✅ Your application code is NOT affected by copyleft ❌ Modifications to TrailBase must be shared under OSL-3.0

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Clients: Apache-2.0

All TrailBase client libraries are dual-licensed under the permissive Apache-2.0 license. Client libraries:

• JavaScript/TypeScript
• Dart/Flutter
• Rust
• C#/.NET
• Swift
• Kotlin
• Go
• Python

What this means: ✅ Use in any project (open or closed source) ✅ No copyleft requirements ✅ Modify freely without sharing changes ✅ Commercial use without restrictions

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Why OSL-3.0?

TrailBase uses OSL-3.0 instead of more common copyleft licenses (like GPL or AGPL) due to its narrower definition of “derivative work”.

What is a Derivative Work?

OSL-3.0 defines derivative work as only modifications to TrailBase itself.Not considered derivative:

• Your application connecting to TrailBase over the network
• Static assets served by TrailBase
• WASM components running in TrailBase’s runtime
• Using TrailBase as a framework or library

This is similar to the GPL’s classpath exception or LGPL’s linking exception.

Comparison with Other Licenses

License	Your App Affected?	Network Use Triggers Copyleft?
OSL-3.0	❌ No	✅ Yes (for TrailBase modifications)
GPL-3.0	⚠️ Maybe (if linked)	❌ No
AGPL-3.0	⚠️ Maybe (if linked)	✅ Yes
MIT/Apache-2.0	❌ No	❌ No (permissive)

OSL-3.0 combines:

• Strong copyleft for TrailBase itself (like AGPL)
• Freedom for applications using it (like LGPL)
• Network use transparency (like AGPL)

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Goals of OSL-3.0 for TrailBase

1. Your freedom: Build on and around TrailBase without restrictions
2. Community benefits: Improvements to TrailBase are shared back
3. Horizontal mobility: Reduce lock-in through open source
4. Sustainability: Allow some flexibility for project sustainability

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What You Can Do

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✅ Allowed Without Restrictions

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📝 Requires Sharing (Copyleft)

If you modify TrailBase itself, you must:

1. Make source available: Provide source code to users
2. Use OSL-3.0: License modifications under OSL-3.0
3. Preserve notices: Keep copyright and attribution notices
4. Document changes: Note your modifications

Examples of modifications requiring sharing:

• Changing TrailBase’s Rust code
• Modifying the admin UI
• Altering API behavior
• Custom builds with different features

Not considered modifications:

• Configuration changes
• SQL migrations
• WASM components
• Your application code
• Using TrailBase as-is

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Common Scenarios

Building a SaaS Application

Scenario: You’re building a SaaS product that uses TrailBase as its backend.Answer: ✅ Freely allowed!

• Your application code is not affected
• No need to open source your app
• Commercial use is permitted
• If you modify TrailBase itself, share those modifications

Using WASM Components

Scenario: You write custom WASM components for server-side logic.Answer: ✅ Your WASM code is not affected!

• WASM components are not derivative works
• Keep your components private if desired
• Commercial use is fine
• Client libraries use Apache-2.0 (permissive)

Modifying TrailBase Core

Scenario: You need to modify TrailBase’s Rust code to add a feature.Answer: 📝 Must share modifications

• Your modifications to TrailBase must be OSL-3.0
• Provide source to users of your modified version
• Your application using it is still safe
• Consider contributing upstream!

Embedding in a Product

Scenario: You want to embed TrailBase in your commercial product.Answer: ✅ Allowed!

• Include TrailBase as-is in your product
• Commercial distribution is fine
• Include OSL-3.0 license text
• Provide TrailBase source code (or link to GitHub)
• Your product code remains private

Creating a Fork

Scenario: You want to create a public fork of TrailBase.Answer: 📝 Fork must be OSL-3.0

• Your fork must use OSL-3.0
• Make source available
• Cannot claim to be “official” TrailBase
• Consider contributing to upstream instead

Using Client Libraries

Scenario: You’re using TrailBase client libraries in your app.Answer: ✅ Completely free!

• Client libraries are Apache-2.0
• Use in any project (open or closed)
• No copyleft requirements
• Commercial use is fine

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Contributor License Agreement

Contributors to TrailBase are asked to sign a simple CLA:

Why a CLA?

The CLA:✅ You retain copyright: Contributions remain yours✅ Forever open source: Ensures OSI-approved copyleft license✅ Flexibility: Allows some sub-licensing (like Grafana/Element)✅ Legal clarity: Protects contributors and usersWe’re still refining the exact licensing model for compatibility between OSL-3.0 and more popular licenses. The CLA provides flexibility while guaranteeing open source forever.

What You're Agreeing To

By signing the CLA, you agree:

1. You have the right to contribute the code
2. Your contribution can be licensed under OSL-3.0
3. You retain your copyright
4. TrailBase can sub-license with restrictions (remains copyleft)
5. The project will remain open source

Similar to CLAs used by Grafana, Element, and other successful projects.

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Source Code Availability

OSL-3.0 requires source code availability:

Unmodified TrailBase

If you distribute unmodified TrailBase:

• Link to the official GitHub repository
• Or include the source code
• Include the LICENSE file
• Preserve copyright notices

Modified TrailBase

If you distribute modifications:

• Provide your modified source code
• License under OSL-3.0
• Document your changes
• Make it reasonably accessible
• Include the LICENSE file

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License Exceptions

If the OSL-3.0 license doesn’t work for your use case, exceptions may be available. When you might need an exception:

• You need to modify TrailBase but cannot share changes
• Your legal team has specific license requirements
• Special commercial arrangements

To request an exception: Contact: [email protected] This follows the selling exceptions model established by other open-source projects.

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Additional Resources

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Frequently Asked Questions

Can I use TrailBase commercially?

✅ Yes! Commercial use is explicitly allowed. Your commercial application using TrailBase is not affected by copyleft.

Do I need to open source my application?

❌ No! Your application code is not a derivative work. Only modifications to TrailBase itself are subject to copyleft.

Can I sell a product that includes TrailBase?

✅ Yes! You can distribute TrailBase with your product. Just include the license and provide source code (or link to it).

What if I make a small change to TrailBase?

📝 All modifications must be shared, regardless of size. Consider contributing it upstream!

Are WASM components considered modifications?

❌ No! WASM components are not derivative works. Your WASM code is not affected by OSL-3.0.

Can I use a different license for my WASM components?

✅ Yes! WASM components are your code and can use any license you choose.

What about the client libraries?

Client libraries use Apache-2.0 (permissive, no copyleft). Use them in any project without restrictions.

Do I need permission to use TrailBase?

❌ No permission needed! The license grants you all necessary rights.

Can I remove copyright notices?

❌ No. You must preserve copyright and attribution notices.

What if I'm still unsure?

Reach out! We’re happy to clarify. Email with questions or concerns.

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Summary

TrailBase’s licensing is designed to be fair and clear:

• Use freely: Build applications without restrictions
• Share improvements: Modifications to TrailBase are shared with the community
• Permissive clients: Client libraries have no copyleft
• Commercial friendly: Use in commercial projects
• Open forever: TrailBase will always be open source