Claude Opus 5.5 Builds iPhone Duo App

This project showcases a two-screen application that integrates an Excalidraw-style board and a sticker maker, aiming to deliver high-quality app functionality without traditional coding.

To achieve optimal performance when developing for the device, engineers should use a Mac with at least an M1 processor, the Claude desktop application for code generation, Xcode version 27.1 beta for simulator support, and optionally, Convex for backend data persistence.

The development environment further includes the Claude desktop app for code generation, Xcode with simulator support (specifically version 27.1 beta for Duo compatibility), and Convex as an optional backend database for data persistence.

Brown outlined the conceptual design for the iPhone Duo app, intending to integrate an image or sticker generator on the right screen and an Excalidraw-style board on the left.

The application's functionality is designed to allow users to generate custom stickers, potentially from image searches or AI-generated people, and then drag these stickers onto the interactive board.

The overall objective is to create a unified workspace that facilitates seamless interaction and full-screen toggling between these two distinct tools within a single application.

The project setup involves establishing a dedicated directory for application files and employing the 'Claude Code' interface, which provides an agentic environment for managing the codebase instead of the standard chat version.

This initial setup involved creating a dedicated directory to house the application's code, preparing the environment for AI-driven development.

A basic "Hello World" app was then built in Swift and run on the iPhone Duo simulator to ensure proper connectivity and functionality of the development tools.

Brown prompted Claude Opus 5.5 to construct an app specifically designed for the iPhone Duo, outlining the core requirements of an Excalidraw-style board on the left and a sticker maker on the right.

The prompt included visual references, such as Twitter screenshots and AI-generated images, to guide the AI in the aesthetic and functional design.

Claude was instructed to search the internet for best practices in designing apps for the new iPhone Duo and to utilize local database storage for the initial prototype phase.

API keys were provided directly to the Claude agent to enable these integrated features, though Brown noted this is not standard best practice for security.

The application generation process was completed in approximately 37 minutes, resulting in a fully functional dual-screen app.

The final product features an interactive board where users can search for images, convert them into stickers, and place them on the digital canvas.

Brown demonstrated the full-screen capability of the Excalidraw-style board, highlighting the seamless integration of functionalities.

Future plans include migrating the local data storage to a cloud-based solution using Convex to enhance data persistence and sharing capabilities.

The completed app successfully allows for document creation, sticker conversion, and drag-and-drop placement on the board, with the AI agent completing the implementation in approximately 50 minutes.

A key feature highlighted was the ability to create share links via Convex, enabling external users to view the boards in a web browser.

Real-time synchronization was confirmed, as edits made on the mobile app instantly reflected in the shared browser view, demonstrating the integrity of the iterative design changes while maintaining database consistency.

Brown requested a cleaner front-end design, aiming to minimize header clutter and potentially reduce the number of buttons to a single full-screen option.

Additional refinements included adding an animation for image-to-sticker conversion, renaming the app to 'Native Board', and implementing search bar filtering to suggest existing stickers based on search terms.

The Native Board application demonstrates real-time board updates across various browser instances, a capability attributed to its integration with Convex.

Stickers are stored in a database, allowing for filtering by query strings like 'Sam' or 'co-pilot', and the app's layout dynamically adjusts to both vertical and folded orientations of the iPhone Duo, ensuring versatile user experience.

The repository will include comprehensive setup instructions, particularly for users unfamiliar with Xcode, with the goal of providing a template for other developers to experiment with iPhone Duo software.

The Native Board app was developed using Claude Opus 5.5 as the primary model, handling both front-end and back-end logic, and integrated Serper API for image search and Remove.bg for sticker background removal.

Convex facilitated real-time data persistence and sharing features, with the entire development process completed in just five prompt iterations.