Dohyun Jung - Principal Consultant, ROBOCO

TL;DR

  • The GPT-4.1 family is a developer-focused lineup built around coding, instruction following, and long-context handling.
  • GPT-4.1 Mini and Nano are presented as solid options for work that needs fast responses and cost efficiency.
  • From a vibe coding perspective, the key point is that Windsurf’s free-usage event lets you try the models out without any financial commitment.

Introduction - OpenAI Releases GPT-4.1, Built for Software Development

In the early hours of April 15, 2025 (KST), OpenAI announced GPT-4.1, a new product family for developers. The family consists of GPT-4.1, GPT-4.1 Mini, and GPT-4.1 Nano, the smallest, fastest, and cheapest model of the three. These models improve on GPT-4.0 and can handle long contexts of up to 1 million tokens.

On top of that, Windsurf is running an event that makes GPT-4.1 available for unlimited, free use for one week starting today, through April 21. Literally free for users on every plan, including the free tier, though throttling to prevent abuse applies just as it does for other paid models. As an aside, word is that the Windsurf development team internally rates GPT-4.1 very highly.

In this post I’ve summarized the main characteristics of GPT-4.1 based on OpenAI’s GPT-4.1 introduction video on YouTube. I used DeepSRT to summarize and organize the video.

Introducing the GPT-4.1 Family

  • GPT-4.1 excels at coding, understanding complex instructions, and building agents
  • GPT-4.1 Mini is faster and suits slightly simpler use cases
  • GPT-4.1 Nano is useful for a range of applications such as autocompletion, classification, and extracting information from long documents

Improved Coding Ability

  • On SWEBench, GPT-4.1 reached 55% accuracy, a major improvement over GPT-4.0’s 33%
  • On the Ader polyglot benchmark, GPT-4.1 shows improved coding ability across a variety of programming languages
  • In a flashcard app example, GPT-4.1 produced frontend code that was far more functional and far better looking than GPT-4.0’s

Stronger Instruction Following

  • GPT-4.1 was trained to follow complex instruction sets accurately
  • In internal evaluations, GPT-4.1 performed significantly better than previous models
  • It also produced strong results on external benchmarks such as Scale’s multi-challenge eval
  • New prompting guidelines are provided to help you get the most out of the model

Long-Context Handling

  • GPT-4.1 Mini and Nano are the first models that can handle a 1 million token context (an 8x increase from the previous 128K)
  • In “needle in a haystack” evaluations, the models can pinpoint specific information accurately within long texts
  • On OpenAI’s MRCR evaluation, GPT-4.1 outperforms GPT-4.0 and holds up well all the way to 1 million tokens
  • On the Video MME benchmark, GPT-4.1 achieved 72% accuracy, a state-of-the-art result

Pricing and Other Details

  • GPT-4.1 is 26% cheaper than GPT-4.0
  • GPT-4.1 Nano is the cheapest model, and there is no additional price premium for long-context usage
  • GPT-4.5 will be phased out of the API in order to free up GPU resources
  • GPT-4.1 and 4.1 Mini support fine-tuning, and Nano will be supported soon

Conclusion

Up to now, Claude 3.7 Sonnet has been the popular choice for vibe coding work. But the fact that OpenAI lined up a partnership with Windsurf in advance, then launched a week-long free-usage event alongside the model announcement to win users over, suggests they are quite confident in GPT-4.1. I’d encourage you to take advantage of this Windsurf event and get started with vibe coding at no cost.