GPT-5.5

GPT-5.5 is OpenAI's large language model that powers ChatGPT and serves as the foundation for various specialized applications across consumer and enterprise use cases. The model exists in multiple variants, including GPT-5.5 Instant for faster inference and GPT-5.5 Codex optimized for coding tasks. OpenAI has released successive updates to improve the model's ability to interpret complex user requests and expand its capabilities into health and wellness domains.

The model has become central to OpenAI's broader cybersecurity strategy, powering tools designed to identify and patch vulnerabilities in open-source software and enterprise systems. Recent developer feedback has highlighted performance concerns related to how GPT-5.5 Codex handles its internal reasoning processes. Meanwhile, GPT-5.5 faces increasing competition from international labs, with some newer models reportedly matching or exceeding its performance on specific benchmarks like coding tasks, sometimes at lower cost.