About memista

A small library by Skelf Research. Built because not every project that needs vector search needs a vector database.

What it is

memista is a Rust crate (crates.io/crates/memista) that packages a vector search service into a single binary. It uses SQLite (via async-sqlite) for chunk text and metadata, and USearch for the vector index. An Actix-web layer exposes three HTTP endpoints, with OpenAPI documentation auto-generated by apistos and rendered via Swagger UI, Redoc, RapiDoc and Scalar at /swagger, /redoc, /rapidoc and /scalar.

What it isn't

It is not a distributed database. There is one process, one disk.
It is not yet production-tested at scale — the project's own README marks it experimental (tested under ~100k vectors).
It does not authenticate clients. The server binds to localhost; if you expose it, you reverse-proxy it.
It does not currently accept arbitrary embedding dimensions in the stock build — IndexOptions::dimensions is set to 2 in src/lib.rs. You will edit this before real use. See changing embedding dimensions.

The audience

Rust developers who are bolting retrieval onto something else — an agent, a desktop app, a CLI — and don't want a separate database to run, monitor, and back up. Edge and local-AI workloads where a single binary that writes a .db and a .usearch file next to it is the right shape. See the use cases for concrete examples.

Index details (grounded)

Property	Value	Source
Index backend	USearch 2.19.x	`Cargo.toml`
Algorithm	HNSW (USearch default)	USearch docs
Distance metric	Inner Product (`MetricKind::IP`)	`src/lib.rs`
Quantization	`ScalarKind::F32`	`src/lib.rs`
SIMD	`simsimd` feature on	`Cargo.toml`
Persistence	SQLite WAL + `<db_id>.usearch` file	`src/lib.rs`
Multi-vector keys	`multi: true`	`src/lib.rs`

The default connectivity, expansion_add and expansion_search are passed as 0, which means USearch picks its built-in defaults. If you need to tune recall vs. latency, fork the load_or_create_index helper.

Project

memista is part of Skelf Research. Source on GitHub, published to crates.io, rustdoc at docs.rs, longer-form docs at docs.skelfresearch.com/memista/. Licensed GPL-3.0.