AI Embeddings Models Tutorial: OpenAI, Cohere, Bge
TL;DREmbedding models (OpenAI, Cohere, BGE) turn text into vectors for search and RAG.
Dedicated embedding models are optimized to map text to vectors where semantic similarity = closeness — the retrieval engine behind search, RAG, clustering, and recommendations. Options range from API services (OpenAI, Cohere) to strong open models (BGE, E5). Key choices: dimension (storage/speed), domain fit, and matching the same model for indexing and querying. Good embeddings are half of good retrieval.
Key points
Text → similarity-preserving vectors
Engine behind search, RAG, clustering
API (OpenAI/Cohere) or open (BGE/E5)
Use the same model to index and query
Common mistakes
Mixing embedding models for index vs query
Ignoring domain fit of the model
Over-paying for dimensions you don’t need
Try it: Explain why index and query must use the same embedding model.