What Is Fine-Tuning?
Last updated April 7, 2026
For anyone who wants an AI that actually understands their business, their style, or their field.
The Simple Explanation
AI models like ChatGPT are trained on massive amounts of general information. They can write emails, answer questions, translate languages, and much more. But they're generalists. They know a little about everything, and nothing deeply about your specific needs.
Fine-tuning is the process of taking one of these general-purpose AI models and teaching it your specific style, knowledge, or task. Think of it like hiring a brilliant new employee who's great at everything, and then training them specifically for your job. After fine-tuning, the model doesn't just follow instructions. It already knows what you want.
For example, an architecture firm could fine-tune a model on their building code documentation and past project notes, and get an AI assistant that answers technical questions the way a senior architect would. A small online shop could train one on their product catalogue and support history, and have a customer support bot that knows every product, every policy, every edge case.
Fine-tuning takes a general model and your data, and produces a small custom adapter.
Prompting vs Fine-Tuning
If you've used ChatGPT or similar tools, you already know about prompting. That's when you type instructions at the start of a conversation, something like "You are a friendly customer support agent for a pet store. Always be helpful and mention our return policy."
Prompting works, but it has limits:
- You have to repeat your instructions every time you start a new conversation.
- The AI might drift away from your instructions as the conversation gets longer.
- Complex instructions can confuse the model or get partially ignored.
- You're using up your message space on instructions instead of your actual question.
Fine-tuning solves these problems by baking your instructions directly into the model's behaviour. Instead of telling it what to do every time, you teach it once. After that, it just knows.
Prompting is reading from a script every time. Fine-tuning is learning the role.
What You Need
Fine-tuning requires two things:
- A base model: this is the general-purpose AI you're starting from. TuneSalon provides a curated list of high-quality, open models in the Train tab , from compact 3.8B models to powerful 72B ones. You don't need to find or download anything yourself.
- Training data: examples of the kind of conversations or responses you want your AI to produce. This could be customer support transcripts, writing samples, Q&A pairs, or anything that shows the AI how you want it to behave. TuneSalon's Dataset tool can even generate training data from your existing documents. Just upload a PDF or text file and it creates structured examples for you.
That's it. You don't need coding skills, a powerful computer, or a PhD in machine learning. TuneSalon handles the technical side; you just bring the knowledge.
What You Get
After fine-tuning, you get a small file called an adapter. This adapter is like a custom lens for the base model. It changes how the model sees and responds to things, without changing the model itself.
The adapter is a small lens that customises the big model, without changing it.
Your adapter is:
- Small. Typically just a few megabytes, compared to the multi-gigabyte base model.
- Reusable. Load it in the Chat tab whenever you want your custom AI, unload it to go back to the base model.
- Shareable. Save it to your Library, or publish it on the Marketplace for others to use.
- Stackable. Combine up to 5 adapters to blend different skills and styles.
Your Data, Your Model
Your training data is used only to create your adapter. It's not stored or shared with anyone else. Once training is complete, the adapter is yours. Keep it private in your library, share it with your team, or sell it on the marketplace. You own it, full stop.
If privacy is your top priority, TuneSalon is also building a desktop app that runs entirely on your own computer. No data leaves your machine. Same fine-tuning power, complete offline privacy.
What's Next?
Now that you know what fine-tuning is, see where it makes the biggest difference, and whether your use case is a good fit.