OpenAI: gpt-4.1:free

gpt-4.1 is the flagship variant of OpenAI's GPT-4.1 family, officially designated as the "Smartest non-reasoning model." It marks a significant advancement over GPT-4o, with substantial improvements in coding reliability and instruction-following precision. Its standout technical breakthrough is the 1-million-token context window, enabling the processing of entire monorepos, extensive legal documents, or massive event logs in a single pass. The model is trained for high "literal adherence," following complex formatting and logic far more accurately than its predecessors. It also introduces optimized code-diffing capabilities, allowing for precise edits that reduce both cost and latency for developers.