Developer FAQ

Do I need to use Day to create my app, or can I use Flutter, React Native, Skip, etc.?

App Fair apps must be conventional Day projects. Start with the standard Day app instructions, then add the App Fair publication configuration. Existing Day apps can add the same configuration without recreating their source; the current repository naming requirements still apply. Day supports creating apps not just for iOS and Android, but also HarmonyOS, Windows, Linux, macOS, and the Web. This provides the necessary foundation for the App Fair to expand to include other storefronts and distribution channels over time.

Do I need to use any specific software license for my app?

No. The app’s source must be publicly available under a license that meets the Debian Free Software Guidelines (DFSG). All dependent software, including every transitive dependency, must meet the same requirement, with licenses compatible with distribution together. The DFSG are guidelines for assessing licenses, not a license you can apply to your code.

Choose a DFSG-compliant license whose terms permit distribution with the code you use. Retain applicable license texts, exceptions and notices, including those required by third-party code. See license and dependencies.

Can I use binary dependencies such as Maven JARs?

Yes, but only if the corresponding source is publicly available under a DFSG-compliant license and the released binary can provably be reproduced by building that source. This applies to direct and transitive binary dependencies. Supply the exact source revision, build instructions and environment, and verification evidence for the binary used. Publishing a source JAR or downloading from Maven Central does not, by itself, establish reproducibility.

Passing automated lint or rebuilding the app with the same prebuilt dependencies does not prove that those dependencies match their source.

Do I need an Apple or Google developer account to distribute to the App Store or Play Store through the App Fair?

You do not need your own Apple or Google developer account to distribute an open-source app through the App Fair. You only need a GitHub account to maintain the source and submit catalog pull requests. Approval by the App Fair and subsequent App/Play Store review are still required for all new app submissions and updates. The App Fair Publisher installation is required. See approval and deployment.

Am I required to distribute my application exclusively through the App Fair?

You own the apps you create and can distribute them through any channels you choose. The App Fair does not require exclusivity.

The App Fair Publisher installation is required while distributing through the App Fair. To withdraw, notify the App Fair through your catalog pull request or a catalog issue, and revoke the Publisher’s access. Revoking access does not automatically remove existing store listings; request removal explicitly if that is what you intend.

Does the app token have to match the app name?

The token is an arbitrary, unique project identifier; it does not have to match the display name. An app called Field Notes can use Orbit-Notes as its token. The GitHub organization and repository must both use that token: Orbit-Notes/Orbit-Notes. The organization name must be available on GitHub. See choosing a token.

What OS do I need to use to develop apps?

You can develop the Android version of your app on Windows, Linux, or macOS; Android Studio and the Android emulator run on all three. Local iOS builds and testing require a macOS development machine with Xcode. If you do not have a Mac, GitHub continuous integration (CI) can build and test both the iOS and Android versions and generate screenshots. Keep both targets enabled in your project and CI workflow. See local testing and CI results.

Are VSCode and the GitHub CLI required?

Both are optional. The day CLI builds, launches and tests the app without an IDE. Use Git for commits and pushes, and GitHub’s website for repository creation and pull requests. The guide’s GitHub website tabs provide instructions that do not require gh. See creating the repository.

Do I need to enable the website for my app repository?

The repository’s GitHub Pages site must remain enabled and published at its expected location: https://app-token.github.io/App-Token/, for example https://games-fair.github.io/Games-Fair/. Preserve the repository name’s capitalization in the URL path.

You do not have to publicize this link, and you may create a separate landing page for your app. The generated GitHub Pages site must still remain published because the App Fair uses it during validation and review. You may configure a custom domain for that site if you choose. See publishing the website.

Should I create the GitHub release myself?

Use day metadata --version-bump patch --git-push after committing your app changes. It bumps the version and build number, commits, tags and pushes. Let CI create the pre-release and upload its assets. Do not also create a release through the website or gh release create. Check the tag’s workflow run and wait for the required assets before submitting. See creating a release.

Does publishing a new GitHub release update the store apps?

A GitHub release alone does not request an App Fair update. Submit a catalog pull request for each version, referencing the new release tag and commit. Use day metadata --version-bump patch --git-push to prepare the next release. Keep the existing app token and store IDs. The App Fair reviews the update before signing and submitting it to the stores.

Leave the GitHub release marked pre-release while it is awaiting submission or review by the App Fair. After the catalog pull request is approved and publication succeeds, the App Fair Publisher automatically removes the pre-release status and marks the release Latest. Do not promote it manually. See submitting an update.