⚡ GPT-4.5 API Deprecation

February 2025 → July 2025

Just 4 months of API availability

Where is GPT 4.5? On July 14, 2025, OpenAI officially removed GPT-4.5 from its API platform, marking the end of one of the shortest-lived commercial AI models in the company's history. The deprecation, announced in April 2025, has sent ripples through the developer community and highlighted the volatile nature of the rapidly evolving AI landscape. While GPT-4.5 remains available to ChatGPT Pro users through the web interface, its removal from the API represents a significant shift in OpenAI's strategy and raises important questions about the sustainability of building applications on cutting-edge AI models. ## Background on GPT-4.5 GPT-4.5, internally code-named "Orion," represented OpenAI's most ambitious scaling effort to date when it launched in February 2025. The model was trained using more computing power and data than any of OpenAI's previous releases, positioning it as the company's largest and most powerful language model. **Key Capabilities and Improvements** GPT-4.5 demonstrated notable improvements over its predecessor, GPT-4o, particularly in areas of creative writing and persuasiveness. The model excelled at tasks requiring emotional intelligence and nuanced communication, making it especially valuable for applications involving writing assistance, coaching, and brainstorming. **Research Preview Status** From its inception, GPT-4.5 was positioned as a research preview rather than a production-ready model. OpenAI framed it as an experimental offering designed to explore the boundaries of large-scale model training and gather insights for future development. This experimental status, while clearly communicated, proved to be a source of confusion for developers who built production systems around the model. **Limitations and Constraints** Despite its impressive scale, GPT-4.5 fell short of OpenAI's internal definition of "frontier level" performance on several industry benchmarks. The model also lacked support for some of ChatGPT's advanced multimodal features, including Voice Mode, video processing, and screen sharing capabilities. Perhaps most significantly, GPT-4.5 suffered from notable latency issues and was reportedly missing key safety guardrails necessary for large-scale deployment. These technical limitations, combined with its experimental nature, ultimately contributed to its brief commercial lifespan. ## Technical and Economic Rationale The decision to deprecate GPT-4.5 stemmed from a combination of technical limitations and economic realities that made the model unsustainable for long-term API deployment. **Prohibitive Operational Costs** GPT-4.5's massive scale came with equally massive operational expenses. The model's pricing reflected these costs, with rates set at $75 per million input tokens (roughly 750,000 words) and $150 per million output tokens. This pricing structure made GPT-4.5 one of OpenAI's most expensive offerings and limited its accessibility to many developers and organizations. OpenAI had warned as early as February 2025 that the company was evaluating whether to serve GPT-4.5 via its API in the long term due to these cost concerns. The extreme computational requirements for inference made the model economically challenging to maintain at scale. **Performance and Reliability Issues** Beyond cost considerations, GPT-4.5 faced several technical challenges that impacted its viability as a production API model: - **Latency Problems**: The model's large size resulted in slower response times compared to more efficient alternatives - **Safety Concerns**: Reports indicated that GPT-4.5 lacked certain safety guardrails that OpenAI considered essential for scaled deployment - **Benchmark Performance**: Despite its size, the model failed to achieve "frontier level" performance on key industry benchmarks ## Migration Path and Alternatives OpenAI provided developers with a three-month transition period and clear guidance for migrating from GPT-4.5 to alternative models, primarily GPT-4.1. **GPT-4.1: The Primary Replacement** Released alongside the GPT-4.5 deprecation announcement, GPT-4.1 emerged as the recommended successor for most API use cases. The model offers several advantages over GPT-4.5:

Model Performance Comparison

SWE-bench Verified

GPT-4.5

Base

GPT-4o

+21.4%

GPT-4.1

+26.6%

MultiChallenge

GPT-4o

Base

GPT-4.1

+10.5%

Video-MME

GPT-4o

65.3%

GPT-4.1

72.0%

**Performance Improvements**: - 21.4% improvement over GPT-4o and 26.6% improvement over GPT-4.5 on the SWE-bench Verified coding benchmark - 10.5% increase over GPT-4o on Scale's MultiChallenge benchmark for instruction following - New state-of-the-art results on Video-MME multimodal long context understanding (72.0% on long, no subtitles category)

Pricing Comparison: GPT-4.5 vs GPT-4.1

$75

GPT-4.5
Input

GPT-4.1
Input

$150

GPT-4.5
Output

GPT-4.1
Output

Input Tokens: 97.3% savings | Output Tokens: 94.7% savings

(Prices per million tokens)

**Economic Benefits**: - Significantly lower pricing at $2.00 per million input tokens and $8.00 per million output tokens - Cached input pricing available at $0.50 per million tokens - Reduced latency compared to GPT-4.5 **Enhanced Features**: - Improved diff format support for more efficient code editing - Increased output token limits (32,768 tokens, up from 16,384 for GPT-4o) - Better instruction following and long-context understanding **Alternative Options** For developers seeking alternatives beyond GPT-4.1, OpenAI's model ecosystem offers several options: - **GPT-4o**: Continued availability with multimodal capabilities - **Reasoning Models**: o1 and o3-mini for tasks requiring step-by-step reasoning - **Specialized Models**: Task-specific models for particular use cases However, developers noted that no single alternative perfectly replicated GPT-4.5's unique combination of creativity, emotional intelligence, and writing quality. ## Conclusion The four-month lifespan of GPT-4.5 in OpenAI's API serves as a stark reminder of the volatility in today's AI landscape. For developers, this deprecation highlights the importance of building flexible applications that can adapt to rapid model changes. The key takeaway is clear: when AI providers label models as "experimental" or "research preview," developers should plan accordingly. The extreme costs and technical limitations that led to GPT-4.5's removal demonstrate that cutting-edge capabilities don't always translate to sustainable commercial offerings. While OpenAI has provided GPT-4.1 as a capable replacement with better performance and lower costs, the rapid pace of change in AI development continues to challenge enterprises seeking stable, long-term solutions. As the industry evolves, the balance between innovation and reliability will remain a critical consideration for both AI providers and the developers who build on their platforms.

📌 Key Takeaways

🕐 Timeline: GPT-4.5 lasted only 4 months in the API (Feb-July 2025)

💰 Cost: At $75/$150 per million tokens, it was economically unsustainable

🔄 Replacement: GPT-4.1 offers 97%+ cost savings with better performance

📖 Lesson: "Research preview" models require flexible architecture planning