What is the difference between fixed-size, recursive, and semantic chunking?

Fixed-size chunking splits text every N characters or tokens regardless of content boundaries, which is fast but often breaks sentences mid-thought. Recursive chunking tries a hierarchy of separators, splitting first on paragraphs, then sentences, then words, preserving structure where possible. Semantic chunking uses embedding similarity between adjacent sentences to find natural topic boundaries, grouping related content together. Recursive is the production default, while semantic chunking improves quality at higher compute cost during ingest.