Build a instant-opening markdown viewer for macOS

Tools

Claude Code

Overview

This essay could have been a prompt.

Workflow

This essay could have been a prompt. I have a markdown viewer. Comes out of the same codebase as my json viewer https://wiki.roshangeorge.dev/w/Blog/2026-04-30/Personal_Sof...I felt the same but if you put it into Claude code Opus 5.5 can build you a program that will open faster than anything you’ve ever used before if you ask for it. I asked for it and it’s instantaneous. Faster than literally any other macOS app.It opens and displays a markdown file faster than bitwarden’s chrome extension displays its fill UI.The future is almost here. Formats and so on are on the threshold of irrelevance in the next few years for this kind of consumer use. It’s hard to even tell if the time it takes us to summarize a text will be the time a future agent takes to write a specialized program that extracts what you need from the file. “Native” support will soon be irrelevant.Even my solution is yesterday’s solution.

Reported result

The author claims the resulting app opens and displays Markdown files instantaneously, faster than any other macOS app and even faster than Bitwarden's Chrome extension UI. However, no independent benchmarks or measured latency metrics are provided in the source to verify these subjective performance claims.

Human role

The original post does not say how a person stayed involved.

Limitations

This approach creates a bespoke tool that does not solve the broader issue of OS-level Markdown support for file sharing. It requires technical proficiency to build and maintain, and may not be suitable for non-technical users who expect files to 'just work' without installing custom software. Source reliability is secondary, based on a forum comment.

Try it

Act as a macOS developer agent. I need a lightweight Markdown viewer built using Swift and SwiftUI, optimized for sub-100ms startup time. 1. Analyze the requirements: The app must open .md files instantly, bypassing heavy rendering engines if possible, or using a highly optimized parser. 2. Generate the project structure and core code for a minimal macOS app that registers as a handler for .md files. 3. Implement a simple text-to-HTML rendering pipeline that prioritizes speed over feature completeness (e.g., skip complex syntax highlighting initially). 4. Provide the Xcode project configuration and build instructions. 5. Create a test plan: Measure the time from double-clicking a 10KB Markdown file to the window appearing. [replaceable inputs: specific macOS version, preferred rendering library, target file size for benchmarking] Before generating the full code, propose the architecture and confirm with me. Do not execute any build commands or install dependencies without my explicit approval. Ensure the code is safe and does not request unnecessary permissions.

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