Fastlane Preview
Fastlane Preview app icon

See your App Store listing before you upload.

Fastlane Preview is a Mac app that turns your local fastlane metadata and screenshots into App Store and Google Play pages. Every device, every language — updated the moment you save a file.

Coming soon to the Mac App Store See how it works ↓

Free to try with a sample project · $9.99 one-time unlock · macOS 14 or later

Fastlane Preview window: a library of seven projects, the App Store product page of the Greenmere sample on an iPhone, and the Source Metadata panel. 1 2 3 4 5
  1. All your projectsOpen or scan fastlane folders. Add as many projects as you like.
  2. App Store or Google PlayIn any language: product page, search result or the localization audit.
  3. iPhone, iPad, Mac or AndroidNine device sizes. Open another window to compare them side by side.
  4. Every limit checkedKeywords count bytes, like Apple does. Click a field to reveal its file.
  5. Edits show up on their ownSave in any editor and every open preview refreshes.

How it works

Every part of the page comes from a file.

Point Fastlane Preview at your project. It reads the folders that deliver uploads and lays them out the way the App Store does — every field in its place, every limit checked.

Top of the page

App Store product page for the sample app Greenmere, rendered by Fastlane Preview: icon, name, subtitle, ratings row and screenshots.

  1. App icon

    AppIcon.appiconset

    Found in your Xcode project or at a common icon.png path.

  2. Name

    name.txt · 30 characters

    See exactly where a long name wraps.

  3. Subtitle

    subtitle.txt · 30 characters

  4. Ratings and age rating

    sample values

    fastlane doesn’t know them, so the preview fills in plausible samples and labels them.

  5. Category and developer

    primary_category.txt
    copyright.txt

    Read from your metadata. The chart position is a sample.

  6. Screenshots

    screenshots/en-US/*.png

    iPhone, iPad and Mac sets stay apart. A language without its own set borrows your primary language’s.

Further down

The same product page scrolled down: promotional text, description, ratings and What’s New.

  1. Promotional text

    promotional_text.txt · 170 characters

    Comes first. Change it any time without shipping a new version.

  2. Description

    description.txt · 4,000 characters

    Follows the promotional text, folded behind “more”.

  3. What’s New

    release_notes.txt · 4,000 characters

    Shown with a sample version number and date.

Not on the page

keywords.txt · 100 bytes

Checked in the localization audit. Apple counts bytes, not characters: 100 bytes hold about 50 Cyrillic or 33 Japanese characters.

Features

Made for real fastlane folders.

Search results

How your name, subtitle and first three screenshots read in App Store search.

Greenmere as an App Store search result.

iPad and Mac

Nine device sizes. iPad pages get iPad screenshots — never stretched iPhone ones.

Greenmere App Store page on a 13-inch iPad.

Google Play too

Title, short and full description, the latest changelog and screenshots from your supply folders.

Greenmere Google Play listing.

Localization audit

Every language in one table: missing fields, missing screenshots and text over the limit.

Localization audit: four languages, the German subtitle is 35 of 30 characters.

Edits show up on their own

Save in Xcode, VS Code or Cursor and every open preview refreshes by itself. Open more windows to watch iPhone and iPad, or English and German, at the same time.

Real-world layouts

Handles the setups projects grow into:

  • metadata/default inheritance
  • symlinked locales
  • metadata-* profiles
  • screenshots/ios and screenshots/macos

For AI-assisted work

Your AI agent writes the metadata. You see the page.

Claude Code, Cursor and Codex will happily write description.txt in twelve languages. Keep Fastlane Preview open next to your terminal and review what they actually wrote, the way App Store visitors will see it — with every limit checked.

A prompt to start with 
Write App Store metadata for this app in fastlane deliver format.
Create fastlane/metadata/en-US/ with one plain-text file per field:
name.txt (max 30 characters), subtitle.txt (30),
promotional_text.txt (170), description.txt (4000),
keywords.txt (100 bytes, comma-separated, no spaces),
release_notes.txt (4000).
Then add de-DE, fr-FR, es-ES and ja folders with translations.
Keep every file within its limit. Keywords count bytes, not characters.

Privacy

Read-only. Local. Yours.

Never touches your files

Projects are opened read-only. Your Fastfile and Deliverfile are never run.

Stays on your Mac

Metadata and screenshots are rendered locally and never uploaded. No App Store Connect login, no API keys.

No account

No sign-up and no tracking. The unlock is an ordinary one-time App Store purchase.

Pricing

Try it free. Unlock once.

Free

Download and explore

The built-in sample project shows everything: product page, search result, localization audit, every device.

US price. The App Store shows the price for your country.

Questions

Do I need fastlane installed?

No. Fastlane Preview reads the folders that fastlane’s deliver and supply use. It doesn’t need Ruby, fastlane or any credentials.

Will it change my files?

No. It only reads. Nothing is written to your repository, and your Fastfile and Deliverfile are never run.

Does it upload anything or connect to App Store Connect?

No. There’s no App Store Connect login, and nothing from your projects leaves your Mac. The app goes online only for the in-app purchase.

Is the preview identical to the App Store?

It’s a close approximation built from reference screenshots of the real stores, not a pixel-perfect copy. Values fastlane doesn’t have — rating, age rating, chart position, size — are filled with plausible samples, and the preview says so.

Which folder layouts are supported?
  • fastlane/metadata/<locale>/*.txt, metadata/default and symlinked locales
  • metadata-* folders for separate metadata profiles
  • screenshots/<locale>, screenshots/ios/<locale> and screenshots/macos/<locale>
  • metadata/android/<locale> for Google Play
How good is the Google Play preview?

It shows the title, short and full description, the latest changelog and phone and tablet screenshots. The Google Play layout is less refined than the App Store one for now.

What’s free and what’s paid?

The app and its built-in sample project are free. A one-time purchase unlocks your own projects.

What are the system requirements?

macOS 14 Sonoma or later, on Apple silicon or Intel.

Is this an official fastlane, Apple or Google product?

No. Fastlane Preview is an independent app by App Machine SIA. It isn’t affiliated with or endorsed by the fastlane project, Apple or Google.