When is an installable app worth building?
Start with how people will use the app. A link may be enough for a form people open once. If they need a home-screen app or features tied to the phone, plan to test what actually installs. a0 builds on Expo, a set of tools for making apps with React Native.
The editor’s browser preview is useful for checking layout and taps on the screen. a0 also advertises web publishing. If a public web link is part of your plan, verify that the required features work in that browser version and check the hosting setup before sharing the link.
If people need to see the same records on more than one device, decide where those records will live. a0 lists Convex and Supabase as backend options. Check which service and project your app actually connects to, and who controls that account.
Can you build one screen you can check yourself?
Start the lunch-packing checklist in a new blank project and keep it unpublished. The preview starts as soon as a project opens. Use a blank project from the start, with fictional inputs and no copied code, settings or service connections. If you can’t confirm that the project is isolated before you open it, sketch the screen and check the expected behavior on paper.
- Describe one small jobAsk for one screen with Bottle, Sandwich and Apple. Tapping an item should mark or unmark it and update the number packed at the top. The sample needs no sign-in or shared storage.
- Check both directionsIn the browser preview, pack Bottle and Sandwich, then unpack Bottle. The count should go from 0 to 1 to 2, then back to 1. Sandwich should still be marked.
- Keep one check for the phoneWhen you have a compatible phone preview or a private test build, repeat the same taps. Check that the marks and count still make sense with larger text and that all three items remain easy to tap.
Which preview can tell you whether the app works?
Use the browser for quick checks and an installed test build for behavior that depends on the phone. For in-app purchases, confirm the app uses separate test connections and the store’s test environment before trying a purchase. On iPhone, use Apple’s sandbox. On Google Play, use an account registered as a license tester and verify that checkout shows a test payment method before tapping Buy. An ordinary account can still be charged on a test track. Stop at the purchase screen if you can’t confirm the test setup.
| Where you test | What you can check | What to confirm first |
|---|---|---|
| Browser preview | Layout, basic navigation and screen behavior. | The preview runs in your browser. A camera, notifications or store purchases may behave differently or be unavailable. |
| Phone preview | How the screen feels on a phone before you make a full build. | Confirm the preview app can open your project’s Expo version. The a0.dev Analytics app listed for iPhone cannot preview projects. Use a compatible preview you’ve verified or the TestFlight route below. |
| Installed test build | Device behavior and features that need the installed app. | Use a0’s documented TestFlight path on iPhone. Direct installation of a test build requires registering the device, and a0’s guide says those steps are still coming. On Android, a0 documents an APK you can install on a test phone. |
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What do you need to release through the app stores?
Choose the developer account that should control each store listing before connecting it to a builder. A build is the app packaged for installation. Uploading a build gives you something to test and submit for the store’s review.
Use screenshots from the build you intend to ship. Base your store privacy answers on the data the app and its connected services actually use.
| Store | What you need | What happens before release |
|---|---|---|
| Apple App Store | Apple Developer Program membership and an App Store Connect app record. Connect the right team and app identifier in a0. | Check that the expected version reaches TestFlight, Apple’s service for inviting testers. Try it with your test group, complete the store listing and submit it for App Review. |
| Google Play | A Google Play Console developer account and an Android App Bundle (AAB) for a new listing. Confirm how you’ll get that bundle before committing to this release path. | a0 documents APK files for phone testing. In Play Console, personal accounts created after November 13, 2023 need a closed test with at least 12 testers opted in for 14 consecutive days before they can apply for public release access. |
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Which changes need a new build?
A change to the Expo runtime, app icon or device permissions calls for a new build. The runtime is the version of the software your app depends on when it starts. a0 documents sending some code and image changes to compatible installed builds that use the same runtime.
Check the runtime in your project’s Build Settings. a0’s public preview and upgrade guides cite different Expo versions, so confirm which preview or test build matches your project. After an upgrade, repeat a familiar task on each platform you plan to release.
What can you pay for before and after launch?
Budget separately for the builder, the stores you publish through and the services your app uses. a0’s public plan page showed these monthly amounts on November 11, 2026. It displays a dollar sign without naming the currency.
Confirm the currency, how tasks use credits and how Max applies its bonus before paying. Apple lists US$99 per membership year, with regional pricing and some fee waivers. Google Play lists a one-time US$25 registration fee. Check any separate charges for the database or other services your app connects to.
| Plan | Displayed amount | What the page lists |
|---|---|---|
| Pro | $20 per month | 100 credits per month, unlimited app builds and code export. |
| Max | $200 per month | 1,250 credits per month and the Pro features. The card separately lists a 250-credit monthly bonus. |
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What should you keep if you move the app out of a0?
a0 lists code export on Pro and Max. Before you rely on the export, check that it has the current app files, images and build settings you need. Find out what you’ll need to build that copy elsewhere and try it with separate test connections.
Keep track of who controls the store listing, the app identifiers and the credentials the store uses to recognize your builds. Plan separately for any saved records, uploads and user accounts. For example, if you connected Supabase, check what is in the database and which files and sign-in settings would need a separate move.