LeanCorpus Monorepo

LeanCorpus is an embeddable, segment-centric full-text search engine for modern .NET. It provides indexing, search, vector retrieval, typed mapping, optional compression and observability without requiring a separate search service.

Note

The core package targets net10.0 and net11.0. It has no external runtime dependencies and is designed for Native AOT.

Build your first search

Install the core package:

dotnet add package LeanCorpus

Create an index, add a document and search it:

using Rowles.LeanCorpus.Document;
using Rowles.LeanCorpus.Document.Fields;
using Rowles.LeanCorpus.Index.Indexer;
using Rowles.LeanCorpus.Search.Queries;
using Rowles.LeanCorpus.Search.Searcher;
using Rowles.LeanCorpus.Store;

using var directory = new MMapDirectory("./my-index");
using var writer = new IndexWriter(directory, new IndexWriterConfig());

var document = new LeanDocument();
document.Add(new StringField("id", "1"));
document.Add(new TextField("title", "The quick brown fox"));
writer.AddDocument(document);
writer.Commit();

using var searcher = new IndexSearcher(directory);
var results = searcher.Search(new TermQuery("title", "fox"), topN: 10);

Console.WriteLine($"Found {results.TotalHits} document(s).");

The program creates ./my-index and prints:

Found 1 document(s).

Tip

Start with Installation and first index, then learn when to use each field type.

Choose the package that matches your job

I want to...	Package	Start here
Embed indexing and search in a .NET application	`LeanCorpus`	First index
Tokenise, analyse or stem text without the search engine	`Rowles.Text`	Rowles.Text README
Generate typed, reflection-free document mappings	`LeanCorpus.SourceGen`	SourceGen README
Use fast LZ4 stored-field compression	`LeanCorpus.Compression.LZ4`	LZ4 README
Use Snappy stored-field compression	`LeanCorpus.Compression.Snappy`	Snappy README
Use Zstandard stored-field compression	`LeanCorpus.Compression.Zstandard`	Zstandard README

The core package already includes Deflate and Brotli. Add a compression package only when its speed or size trade-off fits your workload.

Choose your next path

Build a typed model with the source generator.
Run a complete application from the examples guide.
Understand documents, commits, segments and readers in the architecture guide.
Add metrics, tracing and slow-query logging through observability.
Compare features and trade-offs in Why LeanCorpus?.
Work on the repository using CONTRIBUTING.md.

Native AOT

Validate Native AOT paths in the repository with:

./devops aot

Optional compression packages normally register themselves through module initialisers. Native AOT applications should call the package's Register() method explicitly at startup.

Important

LeanCorpus does not support Blazor WebAssembly. Its segment-centric design requires filesystem and memory-mapped I/O. Blazor Server and Blazor Hybrid remain suitable when indexing and search run server-side.

Monorepo map

Path	Purpose
`src/core/Rowles.LeanCorpus`	Core indexing, search, storage and codec implementation
`src/core/Rowles.Text`	Canonical text-analysis source and standalone package
`src/core/Rowles.LeanCorpus.SourceGen`	Typed mapping source generator
`src/core/Rowles.LeanCorpus.Compression.*`	Optional compression packages
`src/server`	Pre-release server contracts, core and ASP.NET Core host
`src/devops`	Tests, benchmarks, CLI and profiling projects
`src/examples`	Runnable examples and end-to-end workloads
`docs`	DocFX documentation source
`lexicons`	Language data and generated lexicon assets

Plans and discussion

The public roadmap is developed in GitHub Discussions:

Quality

LeanCorpus is licensed under the repository LICENCE.