Publishing

Run the CLI from your app's root, or pass --project <dir>. It needs the publish settings and a git checkout.

npx preview publish                  # id = git branch, both platforms; asks for the title
npx preview publish --id task-1 --changelog="- Fixes the login"
npx preview unpublish task-1
npx preview prune

With bun, use bunx preview; with pnpm, pnpm exec preview; with yarn, yarn preview.

What publish does

For each platform, Android then iOS:

1. Builds with expo export:embed --dev false --bytecode, the same step a release build runs. The result is Hermes bytecode with its images beside it, in the folders the native build uses.
2. Works out the key from the compatibility option in your app config, the same way the config plugin did for the build. It records the app version and the native fingerprint either way.
3. Uploads each file once, under its sha256. Files already in the bucket are skipped.
4. Writes the manifest: the files, their hashes and sizes, the changelog and the versions.
5. Adds the preview to the lists, last. An app never sees a preview whose files are not all there yet.

It prints the URL of the list it wrote, so you can open it and check.

The id and the title

The id is the git branch unless you pass --id. QA sees a readable title made from it: -, _ and / become spaces and the first letter is a capital, so task-1-login-fix becomes "Task 1 login fix".

In a terminal, publish asks for the title, prefilled with that; Enter keeps it. --title skips the question, and so does a run with no terminal, such as CI.

On a detached HEAD there is no branch, so pass --id.

The changelog

Every preview has a changelog QA can read in the list. By default it is the commit subjects since the branch left the base branch. The base is --base <branch>, or else the remote's default branch (origin/HEAD), or else main or master.

To write it yourself:

npx preview publish --changelog="- Fixes the login
- New empty state"
npx preview publish --changelog-file CHANGES.md

Use = with --changelog when the text starts with a dash, as a list does.

Replace, unpublish, prune

Replace. Publishing the same id again overwrites its manifest and its entry in the list. A device that downloaded the old one shows Update available.

Unpublish. preview unpublish <id> removes the preview from every build's list and deletes its manifests. A copy already downloaded stays on the device until QA deletes it, shown as Unpublished. The files stay in the bucket.

Prune. preview prune deletes every file no manifest refers to any more. Run it now and then after unpublishing. Nothing runs it on a schedule.

There is no time limit. A preview stays published for as long as you leave it.

One platform, another entry file

npx preview publish --platform android
npx preview publish --entry-file src/main.tsx

--entry-file is passed to expo export:embed. Leave it out when Expo finds your entry on its own.

Compatibility override

--compatibility appVersion or --compatibility fingerprint overrides the plugin option, with a warning. A build made with the other setting would not list the preview, so use it only when you know the build was made that way.

In appVersion mode publish also prints a one-line warning: a native change without a version bump is not detected. See Compatibility.

The lists in the bucket

Two publishes at the same time both end up listed. The lists are written only if nobody wrote in between, and a clash reads again and retries.

Every flag is on CLI.

Next: CI