ButterKit is a native macOS app used by thousands of Apple developers to automate the App Store publishing workflow. Capture screenshots from Xcode Simulator directly into photorealistic 3D device frames, translate into all 50 App Store Connect languages using frontier AI models (bring your own key) or 18 languages for free using on-device Apple Silicon. Upload everything directly via the App Store Connect API. Start with professional templates or from scratch. Link entire folders for input and output, making it a natural fit for Fastlane and CI/CD pipelines. Use custom fonts, add 3D callouts, and utilize MCP support so AI coding tools can automate the entire workflow. Most developers skip localization because the manual effort doesn't feel worth it. ButterKit makes it trivial, so your app shows up in native language search results across every market Apple supports. Built by a solo developer for developers who ship. Smooth.