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Build Your Own Data Pipeline

Your AI is only as good as its data.

In 30 minutes you'll build the pipeline that turns messy real-world documents into clean, structured AI fuel.

It starts with choosing a messy document.

Chapter 1: The Mess

Real data is ugly. PDFs with tables. HTML with ads. CSVs with missing fields. Scanned images.

Before your AI can learn anything, someone has to clean this up. That someone is your pipeline.

Choose Your Poison

Click on a document type to see what goes wrong:

📄
PDF Report
Tables become gibberish
🌐
Web Page
Ads mixed with content
📊
CSV File
Missing fields, bad encoding
🖼️
Scanned Document
Text locked in pixels
📝
Word Document
Formatting chaos

Chapter 2: Extraction

Pull text from anything. PDF parsing (layout-aware vs raw text), HTML to markdown, OCR for images, table extraction.

Extraction is 90% of the work and gets 10% of the attention.

Build an Extraction Pipeline

Paste a URL or upload content to extract:

OR

Chapter 3: Chunking & Cleaning

Raw text → clean chunks ready for embedding or training. Remove boilerplate, normalize whitespace, handle Unicode, split at natural boundaries.

The wrong chunk size is why your RAG doesn't work.

🔗 Connection: You saw chunking in Build Your Own RAG. Here's the deeper truth: bad chunks are the #1 reason RAG systems fail. This chapter is why your RAG from Course 2 might need a revisit.

Test Chunking Strategies

Apply different chunking strategies to see the results:

Fixed-Size Chunking

Split every N characters

Sentence Splitting

Split at sentence boundaries

Paragraph Splitting

Split at paragraph breaks

Semantic Chunking

Split by topic/meaning

Chapter 4: Labeling & Annotation

For fine-tuning and eval, you need labeled data.

Labeling is boring. It's also the highest-leverage thing you can do for your AI.

Build an Annotation Interface

Label 10 examples to see how annotation works:

Customer Review Sentiment Analysis
Loading example...
1 / 10

Chapter 5: Synthetic Data

Not enough real data? Generate it. Use a strong model to create training data for a smaller model.

The best AI companies all use synthetic data. The bad ones pretend they don't.

Generate Synthetic Training Data

Write a generation prompt to create training examples:

⚠️ Contamination Warning

Synthetic data can inherit biases and patterns from the generating model. Always validate against real-world examples and avoid training on your own model's outputs (model collapse).

// Contamination check
function checkContamination(syntheticData, trainingData) {
  const similarities = syntheticData.map(synthetic => 
    trainingData.map(real => 
      calculateSimilarity(synthetic, real)
    ).max()
  );
  
  const highSimilarity = similarities.filter(sim => sim > 0.9);
  return {
    contaminationRate: highSimilarity.length / syntheticData.length,
    flagged: highSimilarity.length > 0
  };
}

🔄 You Built a Data Pipeline!

From messy documents to clean, labeled, AI-ready data.

This is the foundation every AI system needs.

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