There are a variety of techniques⁠(opens in a new window) that developers can use to increase model performance in an effort to reduce latency, improve accuracy, and reduce costs. Whether it’s extending model knowledge with retrieval-augmented generation (RAG), customizing a model’s behavior with fine-tuning, or building a custom-trained model with new domain-specific knowledge, we have developed a range of options to support our customers’ AI implementations. Today, we’re launching new features to give developers more control over fine-tuning with the API and introducing more ways to work with our team of AI experts and researchers to build custom models.

We launched the self-serve fine-tuning API⁠(opens in a new window) for GPT‑3.5 in August 2023. Since then, thousands of organizations have trained hundreds of thousands of models using our API. Fine-tuning can help models deeply understand content and augment a model’s existing knowledge and capabilities for a specific task. Our fine-tuning API also supports a larger volume of examples than can fit in a single prompt to achieve higher quality results while reducing cost and latency. Some of the common use cases of fine-tuning include training a model to generate better code in a particular programming language, to summarize text in a specific format, or to craft personalized content based on user behavior.

For example, Indeed⁠(opens in a new window), a global job matching and hiring platform, wants to simplify the hiring process. As part of this, Indeed launched a feature that sends personalized recommendations to job seekers, highlighting relevant jobs based on their skills, experience, and preferences. They fine-tuned GPT‑3.5 Turbo to generate higher quality and more accurate explanations. As a result, Indeed was able to improve cost and latency by reducing the number of tokens in prompt by 80%. This let them scale from less than one million messages to job seekers per month to roughly 20 million.

Today, we’re introducing new features⁠(opens in a new window) to give developers even more control over their fine-tuning jobs, including:

At DevDay last November, we announced⁠ a Custom Model program designed to train and optimize models for a specific domain, in partnership with a dedicated group of OpenAI researchers. Since then, we've met with dozens of customers to assess their custom model needs and evolved our program to further maximize performance.

Today, we are formally announcing our assisted fine-tuning offering as part of the Custom Model program. Assisted fine-tuning is a collaborative effort with our technical teams to leverage techniques beyond the fine-tuning API, such as additional hyperparameters and various parameter efficient fine-tuning (PEFT) methods at a larger scale. It’s particularly helpful for organizations that need support setting up efficient training data pipelines, evaluation systems, and bespoke parameters and methods to maximize model performance for their use case or task.