OpenAI Codex を活用した 5 つの楽しいプロジェクト

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# Introduction

OpenAI Codex is one of the most useful tools for building software with AI. Instead of only asking for code, you can use it to plan features, edit files, fix bugs, connect tools, and turn ideas into working projects faster. If you are new to Codex, start with this tutorial first: OpenAI Codex Full Tutorial in 2026 | Using Codex from Scratch. It shows how Codex works on a real project from start to finish. You will see how to give instructions, improve the app step by step, and use Codex like a coding partner. Once you know the basics, these five project tutorials** are a good way to see what you can build with Codex.

# 1. Building Your First App in Minutes

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This tutorial is the best one to start with. It shows how to build a simple app step by step using Codex. The focus is on getting something working quickly without too much complexity. You can use this video to understand the core workflow: describe what you want, let Codex generate or modify the code, review the output, test the app, and keep improving it through follow-up prompts.

# 2. Building a Mobile App with OpenAI Codex

This tutorial is useful if you want to see Codex used for mobile app development rather than a basic web app. The video covers building a Swift iOS app with Codex, using tools such as Xcode** and the Codex desktop app. The project is especially interesting because the app itself is designed around a conversational "vibe coding" experience, where users can generate and host apps through natural language. For beginners, the main takeaway is how Codex can support a more complex development workflow involving mobile interfaces, app structure, local tooling, and iterative feature building.

# 3. Building an AI Startup in Just One Week

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This video is essentially about using Codex to go from a simple idea to a full startup-like product in 7 days. They start with a simple idea and use Codex to turn it into a working web app step by step. Along the way, they build basic features, fix problems, and keep improving the product. The main focus is on how Codex can help speed up the whole process of building an app from idea to something usable.

# 4. Vibe Coding a Complete 2D Beat 'Em Up Game From Scratch

This is the most playful project in the list. The tutorial shows how to build a complete 2D beat 'em up game from scratch using Codex, Phaser**, and image generation tools. It is a great example of how Codex can be used outside traditional productivity apps and dashboards. You get to see how AI can help with game mechanics, characters, movement, visuals, and the overall structure of a browser-based game. For beginners, this project is useful because it makes coding feel more creative. You can experiment with prompts, change the style of the game, add new characters, and see how Codex handles interactive features.

# 5. Building a Full-Stack Airbnb Clone

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This is one of the most complete project tutorials on the list. It covers building a full-stack Airbnb-style clone using Codex, Expo, React Native, Stripe, and Supabase**. The app works like a simple vacation rental platform where users can browse places, view details, and go through a basic booking flow. The main idea is to show how Codex can help build a full-stack app step by step, including mobile screens, backend data, authentication or database workflows, and payments.

# Wrapping Up

These projects show how flexible OpenAI Codex can be. You can use it to build a simple first app, a mobile app, a startup prototype, a full-stack clone, or even a 2D game. The best way to learn is to start small, test often, and treat Codex like a coding partner that still needs clear instructions and human review.

Kanwal Mehreen is a machine learning engineer and a technical writer with a profound passion for data science and the intersection of AI with medicine. She co-authored the ebook "Maximizing Productivity with ChatGPT". As a Google Generation Scholar 2022 for APAC, she champions diversity and academic excellence. She's also recognized as a Teradata Diversity in Tech Scholar, Mitacs Globalink Research Scholar, and Harvard WeCode Scholar. Kanwal is an ardent advocate for change, having founded FEMCodes to empower women in STEM fields.