Fine-tuning LLMs

Fine-tuning adapts a pre-trained language model to your specific use case by training it on domain-specific data. It's more powerful than prompt engineering for specialized tasks.

When to Fine-tune

Good Use Cases

  • Domain-specific language (legal, medical)
  • Consistent style/tone
  • Structured output formats
  • Better performance on specific tasks

When NOT to Fine-tune

  • Limited training data (<100 examples)
  • Prompt engineering works well
  • Need frequent updates
  • General knowledge tasks

Fine-tuning Methods

Full Fine-tuning

Update all model parameters. Most effective but expensive.

LoRA (Low-Rank Adaptation)

Freeze base model, train small adapter layers. 90% less memory!

QLoRA

LoRA + quantization. Fine-tune 70B models on consumer GPUs.

Training Data Format

Typical format for instruction fine-tuning (JSONL).

python
Output:
Click "Run Code" to see output

Pro Tip: Start with 50-100 high-quality examples. Quality > Quantity!