I Built 6 Apps with ChatGPT-5 (Vibe Coding Test)

Key Concepts

• Vibe Coding: A development methodology where applications are built primarily through natural language prompting rather than manual coding.
• Thinking Model: A specialized version of ChatGPT-5 that performs deeper reasoning (similar to o3) before generating responses.
• Context Window: The amount of data (tokens) the model can process at once; ChatGPT-5 has increased this to 400,000 tokens.
• Verbosity Parameter: A new API setting that allows users to control the length and detail level of the AI's output.
• Hallucination: Instances where the AI generates incorrect or nonsensical information; ChatGPT-5 shows reduced rates compared to previous versions.

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1. Application Demos and Use Cases

The creator tested ChatGPT-5 by building six distinct applications using "vibe coding."

• Solar Spaceship Game: A complex simulation using Next.js, D3, and Canvas. It features physics, asteroid generation, and lighting effects. The creator noted that while the AI handled the visuals well, manual refinement was required for specific details like texture and physics.
• Pixel Art Editor: A browser-based tool allowing grid customization, zooming, painting, and PNG exporting. This was completed in 20 minutes with minimal iteration.
• Neon Snake Game: A classic arcade game implementation that worked effectively on the first prompt ("one-shot").
• Landscape Simulator: A procedural world generator featuring cities, buildings, and vehicles. It demonstrated the AI's ability to handle complex parameters like "roughness" and "height," though some minor spatial bugs (e.g., floating streets) occurred.
• Coin Market Cap Clone: A financial data app using the CoinGecko API and a charting library from Interactive Brokers. This required advanced React knowledge to integrate a non-React-native library, highlighting that while AI is powerful, developer expertise is still necessary for complex library integrations.
• Typeform Clone: A dynamic form builder with webhook support. This project demonstrated the potential for monetizable SaaS products, as the AI successfully handled the logic for form creation, data submission, and dashboard management.

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2. Technical Specifications and Model Improvements

The video highlights several technical updates in the ChatGPT-5 ecosystem:

• Model Variants:
  • ChatGPT-5 (Thinking): Optimized for complex reasoning tasks.
  • ChatGPT-5 (Latest): The standard, non-thinking model.
  • ChatGPT-5 Nano: A highly cost-effective model for API usage, noted to be cheaper than the 4.1 mini version.
• Context Window: Increased from 200,000 tokens (in o3) to 400,000 tokens, allowing for larger codebases to be processed.
• Performance: ChatGPT-5 is described as faster than the o3 model and more factual, with significantly lower hallucination rates.
• Cost Efficiency: The model is positioned as a major cost-optimization tool. It is approximately 7.5x to 12.5x cheaper than Claude Opus 4.1, making it highly competitive for high-volume API tasks.

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3. Methodologies and Frameworks

• Iterative Prompting: The creator emphasizes that "vibe coding" is not always a one-shot process. Complex apps (like the spaceship game) required iterative refinement to add specific features like textures, shadows, and physics.
• Integration Strategy: For complex tasks (like the Coin Market Cap clone), the AI acts as a co-pilot. The user must provide the architectural "glue"—specifically when integrating third-party libraries that are not natively compatible with the chosen framework (React).

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4. Key Arguments and Perspectives

• Accessibility: The creator argues that "vibe coding" democratizes software development, allowing non-programmers to build functional, visually impressive applications.
• Evolution vs. Revolution: The creator concludes that ChatGPT-5 is not a "giant leap" in raw power, but rather a significant optimization in usability, cost, and speed.
• Comparative Standing:
  • Vs. Claude 3.5 Sonnet: ChatGPT-5 is considered superior for coding.
  • Vs. Claude Opus 4.1: ChatGPT-5 is considered slightly worse in performance but vastly superior in cost-efficiency.
  • General Tasks: ChatGPT-5 is described as the best-in-class model for general-purpose tasks.

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5. Synthesis and Conclusion

ChatGPT-5 represents a shift toward pragmatic AI development. While it may not be a revolutionary breakthrough in intelligence, its improvements in context window size, reduced hallucination, and aggressive pricing make it a highly viable tool for rapid prototyping and SaaS development. The "vibe coding" approach is highly effective for UI-heavy or logic-based applications, though developers should still expect to intervene when integrating complex, non-standard libraries. The model is best viewed as a cost-effective, high-speed engine for building functional software with minimal manual overhead.