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This announcement was written by GPT-4.5 itself! Check out the screenshot here.
We have exciting news: GPT-4.5 is now officially available on Chat-O through our Bring Your Own Key (BYOK) option! We’re thrilled to provide you with the very latest advances in conversational AI, empowering you to access unparalleled creativity, enhanced understanding, and richer interactions directly within Chat-O.
GPT-4.5 represents another giant leap forward in the world of AI-generated content. Building upon GPT-4’s impressive capabilities, GPT-4.5 brings you:
GPT-4.5 introduced several architectural refinements. While OpenAI did not disclose exact parameter counts, the model showed measurable improvements across key benchmarks:
| Capability | GPT-4 | GPT-4.5 | Improvement |
|---|---|---|---|
| MMLU | 86.4% | 88.3% | +1.9% |
| HumanEval | 67.0% | 72.6% | +5.6% |
| GSM8K | 92.0% | 94.1% | +2.1% |
| Inference Speed | Baseline | ~2x faster | Significant |
The model also introduced improved instruction following, making it more reliable for structured tasks like JSON generation, API call formatting, and multi-turn workflows.
Our BYOK option empowers you to use your own OpenAI API key while interacting with Chat-O, giving you control, security, and ease of personalized use. Connect your API key seamlessly within our secure platform, ensuring your private and tailored AI experience.
BYOK remains one of Chat-O’s most popular features, especially for users who already have OpenAI API access through work or personal subscriptions. It allows you to:
Since GPT-4.5’s launch, the AI model landscape has expanded dramatically. OpenAI has since released GPT-5.1 in the Power tier, offering significantly improved reasoning and a larger context window. However, GPT-4.5 remains available for users who prefer its particular balance of speed and capability.
Chat-O was still in closed beta at the time of this post, but we were actively adding more users each day. Our community has been pivotal in refining our features and improving platform performance, ultimately providing a smoother and richer AI conversational experience.
Since then, Chat-O has fully launched and grown to support over 50 models across Light, Balanced, and Power tiers. The platform has evolved from a single-model chat interface into a comprehensive multi-model AI workspace. For a full perspective on how far we have come, see our GLM-5.2 vs Kimi K3 comparison for a look at today’s frontier models.
| Model | Release | Context | Key Strength |
|---|---|---|---|
| GPT-4.5 | Feb 2025 | 128K | General purpose, conversational |
| GPT-5 | Nov 2025 | 256K | Improved reasoning, multimodal |
| GPT-5.1 | Nov 2025 | 256K | Advanced reasoning, coding |
While GPT-4.5 has been superseded by GPT-5.1 in terms of raw capability, it still holds up well for everyday conversations, content generation, and tasks where its particular conversational style shines.
Despite being an older model, GPT-4.5 remains excellent for:
When GPT-4.5 launched on Chat-O, the platform featured a handful of models in a closed beta. Today, Chat-O offers:
For the full current lineup, check out our Z-AI GLM family overview and Kimi family lineup.
Ready to experience GPT-4.5? Join our growing Chat-O community and be one of the first to experience the future of conversational AI. Spaces are limited but users are getting invited daily — secure your spot today!
Sign Up Now and get 1,000 free credits!
We’re excited to have you onboard—thank you for your support as we continue pushing the boundaries of AI-driven conversations together.
Stay tuned for more exciting updates from Chat-O!