ButterKit

ButterKit is a macOS app designed to help developers create, localize, and publish App Store screenshots and metadata. Built by solo developer Zach Spitulski, it positions itself as an all-in-one "screenshot studio" that streamlines one of the more tedious parts of shipping an iOS, iPadOS, macOS, watchOS, or visionOS app — preparing polished marketing visuals and translating them into every language the App Store supports.

The workflow centers on three stages. First, capture: you can drag and drop PNG/JPG images directly onto 3D device mockups, capture screenshots straight from Xcode Simulator, or link a folder (compatible with Fastlane or Xcode UI test outputs) so new builds automatically refresh your designs. Second, design: ButterKit ships with a Metal-powered 3D rendering engine (up to 120fps) that places your screenshots inside photorealistic, editable device frames. You get professional templates, font and gradient controls, and the ability to span devices across multiple artboards for panoramic layouts. A community marketplace adds more templates and add-ons. Third, translate and publish: it can auto-translate screenshots and metadata into all 50 App Store languages in seconds, then upload everything directly to App Store Connect via the official API — no manual browser dragging required.

Translation uses two engines: a free on-device option covering 18 languages (offline, private, no API key) and a Pro cloud option for all 50 languages using your own API key. Pro also unlocks metadata syncing for fields like "What's New," description, and promotional text across every localization, and removes the "Made with ButterKit" watermark.

Notable extras include a built-in Model Context Protocol (MCP) server, which lets AI coding agents like Claude Code, Cursor, and Codex automate the entire screenshot, translation, and publishing pipeline. Some Android support exists too, with a Pixel 10 Pro 3D model included.

ButterKit runs entirely on your Mac with no servers or accounts, which is why it offers a one-time purchase option alongside subscriptions. System requirements are macOS 15.6+, with best performance on Apple Silicon. There's a free tier, a 14-day refund policy, and 50% discounts for students, educators, veterans, and first responders.

The marketing positions it against legacy design tools (like AppLaunchpad, AppScreens, Helm) and generic AI image generators, emphasizing real editable 3D mockups, no ads or signups, and direct Xcode/App Store Connect integration. Testimonials from indie developers consistently highlight speed and simplicity. It's a focused, self-funded indie product squarely aimed at Apple platform developers who want App Store assets done quickly without sacrificing polish.