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What is PistaDB?

PistaDB is a lightweight embedded vector database written in pure C99 with zero external dependencies. It ships as a single shared library and stores everything in a single .pst file.

It is designed for local RAG pipelines, offline AI agents, privacy-sensitive applications, edge inference, and anywhere shipping a full vector database cluster is impractical — which, honestly, is most places.

PistaDB vs. cloud / server vector databases

PistaDBCloud / Server Vector DB
DeploymentCopy a .dll / .soDocker, Kubernetes, cloud subscriptions
StorageOne .pst fileSeparate data + WAL + config + sidecar files
PrivacyAll data stays localEmbeddings sent over the network
MemoryConfigurable, minimalGBs of JVM / runtime overhead
DependenciesNone (pure C99)Dozens of packages
LatencySub-millisecond on a laptopNetwork round-trips
CostFree forever (MIT)Per-query or per-vector pricing

When PistaDB fits

  • Desktop apps that need semantic search without phoning home.
  • Mobile RAG (Android via JNI, iOS via Swift Package Manager).
  • Edge / MCU inference (experimental ESP32 component).
  • Embedded analytics inside an existing C/C++/Go/Rust application.
  • Notebook prototyping before deciding whether a cluster is even needed.

When it doesn't

  • Multi-tenant SaaS with thousands of concurrent writers — use a server DB.
  • Datasets that don't fit on a single machine — PistaDB scales to ~10 M vectors per file, not 10 B.
  • Workloads that need a managed control plane, replication, or distributed consensus.

Next steps

Released under the MIT License.