GPT-4.1 is OpenAI's flagship language model optimized for coding, instruction following, and long-context reasoning, released in April 2025. It supports a 1-million-token context window — over 8× the capacity of GPT-4o — and achieves 54.6% on SWE-bench Verified, representing a major improvement in real-world software engineering tasks. The model excels at precise code diffs, agent reliability, and high recall across large document contexts, making it well-suited for IDE tooling, automated coding agents, and enterprise knowledge retrieval.