K2Coder is a Mac app that builds software from a description. You tell it what you want — a website, a React web app, a Node API, an iPhone app — and it creates the project, runs it, and shows you the result inside the app. It is free to download from quantumaccordbg.com/k2coder, signed and notarised by Apple, and runs on macOS 14 or later on both Apple silicon and Intel Macs.
This post is about what it does, what it deliberately does not do, and how it treats the AI keys you give it.
What you actually get
Projects, like Xcode. New project, pick a kind — website, React web app, Node API, or iPhone app — and describe it. K2Coder writes the files, installs what they need, and runs the result with one button. A Preview pane shows it live.
It checks its own work. This is the part that separates it from pasting code out of a chat window. After building a page, K2Coder opens it in a real browser at phone width and at desktop width, clicks through it, and fixes what is broken before showing you. A layout that collapses on a phone gets caught by the app, not by your first visitor.
iPhone apps. SwiftUI projects that build with Xcode and run in the iPhone simulator, with the live simulator screen inside K2Coder. You need Xcode installed for this; the app tells you if it is missing rather than failing quietly.
It remembers your project. Each project keeps a small wiki of the decisions and conventions made along the way, so the next session starts where the last one ended instead of re-deriving your folder structure.
Many AI models, your choice. Gemini, OpenAI, DeepSeek, Kimi, local models running on your own Mac, and Claude through your own Claude plan. You are not locked to one vendor, and you can move a project between them.
What it does not do
It does not host anything. K2Coder builds and runs on your Mac; putting a site on the internet is a separate step, and the app does not pretend otherwise.
It is not finished for Windows. A Windows build is being made now. The download page takes an email address and tells you when it exists — it does not offer a file that is not there.
It does not phone home with your code. Projects live on your disk.
Where your keys go
Provider keys — the API keys for Gemini, OpenAI and the rest — live in your Mac's Keychain. They never reach the commands the AI runs. That distinction matters: an AI agent that can run shell commands is one prompt-injection away from cat ~/.zshrc, and the only defence that works is for the secret not to be in any place the agent can read. K2Coder is built that way.
Download
Version 1.1.0 for macOS, 88 MB, free, no account needed: quantumaccordbg.com/k2coder. The file is served from private storage through a link that expires after a few minutes, so a link pasted into a forum stops working and an old build can never outlive its replacement.
Windows: leave your address on the same page.
Who it is for
Freelancers and small studios who need a working site or app faster than they can write it, and who would rather check a running result than read generated code. If you already know how to deploy a Next.js site, K2Coder gets you to the deploy step; if you do not, the Quantum Accord website builder does the hosting for you.