Chunking Differences Between SynapseKit LangChain LlamaIndex

📣 We ran chunk_size=300 on the same document across three frameworks. SynapseKit: 12 chunks. LangChain: 12 chunks. LlamaIndex: 2 chunks. Same parameter. Same document. Order of magnitude difference in output. Zero error messages. Here's what's happening: LlamaIndex's SentenceSplitter interprets chunk_size as tokens, not characters. chunk_size=300 means 300 tokens — roughly 1,200 characters. On a 1,972-character document that gives you 2 chunks averaging 986 characters each instead of the 12 chunks averaging 163 characters you'd expect. This is documented behavior. It is also the most common source of confusion when engineers copy parameters from a LangChain tutorial into LlamaIndex. Same parameter name. Completely different semantics. Your retrieval quality changes by an order of magnitude and nothing tells you why. The rule: never copy chunk parameters across frameworks without checking the unit. chunk_size=300 means... SynapseKit → 300 characters → 12 chunks LangChain → 300 characters → 12 chunks LlamaIndex → 300 tokens (~1,200 chars) → 2 chunks ⚠ A few other things worth knowing from this benchmark: LangChain ships 8 built-in splitters. LlamaIndex ships 9. SynapseKit ships 2. But two of LlamaIndex's splitters — SentenceWindowNodeParser and HierarchicalNodeParser — have no equivalent in the other frameworks and solve real production problems that the others don't address at all. LangChain's standalone splitter API is the most debuggable. You can inspect chunks before indexing. SynapseKit's chunking is opaque — parameters live on the Retriever and you can't see the split before it's indexed. Chunking is not configuration. It's architecture. The split you choose affects embedding quality, retrieval precision, and whether your LLM gets enough context. The tutorials that sprint past it in two lines are the same tutorials whose RAG demos fall apart on real documents. Full benchmark + reproducible Kaggle notebook → engineersofai.com #Python #AI #LLM #RAG #MLEngineering #OpenSource #AIEngineering #EngineersOfAI #SynapseKit

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