GPT-4.1
By OpenAI
1 is an OpenAI language model released in 2025 as a developer-focused update to GPT-4o, emphasizing improved coding ability, instruction following, and a substantially larger context window.
Definition
GPT-4.1 is an OpenAI language model released in 2025 as a developer-focused update to GPT-4o, emphasizing improved coding ability, instruction following, and a substantially larger context window.
Overview
GPT-4.1 arrived as a family of three models — GPT-4.1, GPT-4.1 mini, and GPT-4.1 nano — aimed squarely at developers building on the OpenAI API rather than at consumer ChatGPT users. It extended the context window well beyond GPT-4o, allowing it to process much longer documents, codebases, and conversation histories in a single request, and OpenAI reported meaningful gains on coding benchmarks and instruction-following evaluations. Like other members of the GPT family, GPT-4.1 is a Transformer-based LLM trained on large text and code corpora and refined with RLHF and instruction tuning. It is positioned between GPT-4o and the more reasoning-heavy o-series models, trading deep multi-step reasoning for speed, cost efficiency, and strong general-purpose and coding performance — making it a popular default for AI agent backends and IDE integrations. GPT-4.1 sits in a lineage that runs from GPT-4 through GPT-4o to GPT-5, each generation trading off latency, cost, and reasoning depth differently for different use cases.
Key Features
- Long context window supporting large codebases and lengthy documents
- Available in three sizes: standard, mini, and nano for different latency/cost needs
- Strong performance on coding and software-engineering benchmarks
- Improved instruction following compared to GPT-4o
- Accessible via the OpenAI API for developer integrations
- Optimized for agentic and tool-calling workflows