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extension/start

License

Last updated: July 30, 2026

This is the license you get when you buy ExtensionStart. The short version: build anything you want with it; just don't resell the kit itself.

You can

  • Build and ship unlimited extensions, commercial or free
  • Build for yourself or for clients, and charge for it
  • Keep your products closed-source, no attribution
  • Modify every line of the code
  • Own your extensions outright; they're yours

You can't

  • Resell or redistribute the kit, or a derivative starter kit
  • Publish the kit's source code publicly
  • Share your repository access with others
  • Cover more than one developer with one license

The terms

  1. What you're licensed to do. Your purchase grants you, one individual developer, a non-exclusive, non-transferable, worldwide, perpetual license to use, modify, and build upon the ExtensionStart source code to create end products.
  2. One developer per license. A license covers one named person writing code with the kit. It doesn't cover a team, a company, or "whoever is working on the project this month"; each developer who works with the kit's source needs their own seat.
  3. Teams and companies. A team uses the kit by holding one license per developer: two developers, two licenses; purchased under one company or several individual names, it doesn't matter, as long as the seat count matches the people in the code. Teammates who never touch the kit's source (designers, PMs, QA testing your finished extension) don't need seats. For five or more seats, email support@extensionstart.com for volume pricing.
  4. Client work and agencies. You may use the kit to build extensions for clients, and you may buy a license on a client's behalf. The license belongs to the developer seat, not the project: an agency developer with one seat can serve any number of clients, but handing the kit's source to the client's own developers requires those developers to hold seats too. Delivering the finished extension to a client is always fine; that's an end product.
  5. Unlimited end products. There is no limit on what you ship. Build one extension or fifty, free or paid, for yourself or for clients. No royalties, no per-product fees, no attribution required.
  6. Your code is yours; the kit stays ours. Everything you build on top of the kit (your features, your branding, your product) belongs to you, and this license places no claim on it. The kit's source code itself remains the intellectual property of ExtensionStart; what you purchased is the license on this page, not ownership of the code.
  7. What's forbidden. You may not:
    • Resell, sublicense, or redistribute the kit (or anything that is substantially the kit with modifications) as a starter kit, boilerplate, template, code generator, or similar product that competes with ExtensionStart.
    • Publish the kit's source code (or substantial portions of it) publicly, for example in a public repository, package registry, or paste site. Your end products may be open source only to the extent they don't expose the kit itself as a reusable starting point.
    • Share access to the private repository, or copies of the source, with anyone who doesn't hold their own license.
    • Use the kit to build anything unlawful, or extensions designed to deceive or harm their users: malware, spyware, or products built to violate browser-store policies.
  8. Updates. The license includes updates to the repository; see the updates page for exactly what that covers, including what happens if the product is ever discontinued (short version: the source stays yours).
  9. No warranty. The kit is provided "as is", without warranty of any kind, express or implied, including merchantability, fitness for a particular purpose, and non-infringement. You are responsible for your own products, including their compliance with browser-store policies and applicable law. To the maximum extent permitted by law, our total liability is limited to the amount you paid for the kit.
  10. Termination. How this license can end, and what each ending means:
    • If you violate it, the license ends automatically: repository access is revoked and you must stop using and distributing the kit's code. Products you shipped in good faith before termination are unaffected.
    • If your purchase is refunded or charged back, the license ends with it: access is revoked and you may not keep or continue using the source (see the refund policy).
    • If ExtensionStart is discontinued, the license does not end: you keep the source and every right on this page, per the updates page.
  11. Everything else. This license is part of the terms of service, which cover governing law, liability, and how changes are handled. If the two ever conflict about the code, this page wins.

Questions

Unsure whether your use case is allowed? Ask before you buy: support@extensionstart.com. Honest questions get honest answers.