Alternatives to TopK

Pinecone is a managed vector database and knowledge engine for RAG, semantic search, and agent retrieval.

Vespa AI is an open-source AI search platform for hybrid vector, text and structured retrieval with ML ranking in one query pass.

Open-source RAG engine with built-in ETL, hybrid vector/BM25 search and visual agent orchestration for enterprise AI agents.

Milvus is an open-source vector database for billion-scale similarity search, hybrid retrieval, and lake-native RAG workloads

Vespa is an open-source AI search platform for hybrid vector, text, and tensor retrieval with machine-learned ranking.

LanceDB is an open-source multimodal lakehouse that keeps curation, feature engineering, hybrid search, and training on one Lance table.

Apache 2.0 search infrastructure for AI that keeps vectors, indexes and metadata on cheap object storage.

TiDB is a distributed SQL database for AI agents that unifies ACID transactions, HTAP analytics, and native vector search in one engine.

Apache Doris unifies OLAP analytics, full-text search, and vector search in one open-source SQL engine.

Lance is an open lakehouse format for multimodal AI, pairing a file format, table format, and catalog spec with hybrid vector and full-text search on object

Databend is an open-source, cloud-native data warehouse in Rust that runs BI analytics, vector search, full-text search and geospatial on

Self-hosted RAG search engine for private document search — BM25 plus hybrid retrieval across 34 file formats.

NodeDB is a universal database engine that unifies vector, graph, document, columnar, key-value, full-text, sparse arrays, and CRDT in one binary over plain

Multimodal retrieval that indexes video, image, audio and PDF files straight from your S3, GCS or R2 bucket.

Open-source Microsoft Research RAG that builds a knowledge graph and community summaries from your documents, then queries them in four modes.

pgvector brings open-source vector similarity search to Postgres so embeddings live next to your relational data.

Zilliz Cloud: a fully managed vector database on Milvus for billion-scale AI search, RAG, and recommendations.

Elasticsearch Labs: free tutorials, notebooks, and reference apps for AI search, vector search, and RAG on Elasticsearch.

Open-source in-process vector database from Alibaba — install one Python package, query millions of vectors in seconds.

AI-native graph database running vector similarity and OpenCypher traversal in one query for GraphRAG pipelines.

Open-source context retrieval layer that syncs your apps and databases so AI agents query live business data in natural language.

Kronotop is a distributed transactional document database that gives every AI agent or tenant its own namespace with built-in vector search.

RushDB: graph and vector persistent memory for AI agents, where you push JSON and query one connected graph.

HanLP is a production-oriented multilingual NLP toolkit with a deep focus on Chinese, built on PyTorch and TensorFlow 2.x.

Zilliz Cloud Serverless is a managed serverless vector database on Milvus, with auto-scaling compute and tiered storage for GenAI apps.

Memgraph is an in-memory graph database for GraphRAG, AI memory, and real-time graph analytics on one engine.

GRID is a headless spreadsheet engine that gives AI agents goal seek, what-if analysis and cell edits as direct tool calls instead of generated Python.

Xberg is an open-source content intelligence engine that extracts 107 document, web, code, image and audio formats into clean Markdown,

Fenic turns messy text into typed, queryable Semantic DataFrames with LLM-powered extraction, classification, and semantic joins in Python.

Simplemma is a pure-Python multilingual lemmatizer that returns dictionary base forms across 35 languages with zero dependencies.