Stretchy: an edge-native BM25 search engine
Stretchy is a full-text search engine that ranks results with BM25 and runs at the edge, on your own servers, or on machines with no internet connection. It is built for teams that want fast keyword search without running and paying for a search cluster.
What Stretchy does
Stretchy provides fast, deterministic search across enterprise records, telemetry data, and rich documents. Built on a tuned Apache Lucene 9.12.0 core, it executes BM25 relevance scoring with sub-15ms p95 response times on single-node deployments.
In addition to keyword querying, Stretchy features real-time probabilistic anomaly detection using Welford's online variance algorithm. As events flow into the engine, statistical baselines are computed automatically without requiring external machine learning clusters.
Stretchy vs. Elasticsearch and OpenSearch
| Capability | Elasticsearch / OpenSearch | AveLynx Stretchy |
|---|---|---|
| Memory Footprint | 16 GB – 64 GB JVM per node | < 150 MB RAM |
| Cluster Requirement | Required (Master, Shards, Replicas) | Zero (Single container or Serverless) |
| Air-Gapped Operation | Complex offline package management | Native (Zero internet dependencies) |
| Mapping Conflicts | Crashes on type collision | Flattened indexing with raw storage |
| Document Ingestion | Requires Apache Tika plugin (~100MB) | Built-in PDFBox 3.0 & XML streaming |
Deployment options
Stretchy is engineered with a dual execution runtime: deploy as a lightweight Docker microservice on any Linux/Windows host, globally across Cloudflare edge workers, or bare-metal on disconnected infrastructure. Minimum hardware requirements are 1 vCPU, 512MB RAM, and 1GB local storage. See air-gapped search for sovereign environments.
Dynamic query slicing
Stretchy's visual query engine allows non-technical users and automated pipelines to construct multi-clause queries across 11 relational and range operators. Queries compile down to high-performance Lucene DoublePoint and LongPoint trees, eliminating the runtime cost and type errors of raw syntax strings.
Client libraries
Official client libraries are open source under Apache 2.0. Get the TypeScript/JavaScript client and the Tokio-powered async Rust SDK directly from the GitHub repository.
Performance
Stretchy delivers sub-15ms p95 latencies on 100,000+ document indices with zero cluster coordination tax. Review the full methodology and hardware setup on the BM25 benchmarks page.
Common questions
Is Stretchy open source?
The client SDKs (TypeScript and Rust) are open source under the Apache 2.0 license on GitHub. The Stretchy core server is commercial software licensed by AveLynx.
Does Stretchy need a cluster?
No. Stretchy is designed from the ground up to eliminate cluster tax. It runs as a self-contained container or serverless edge function without ZooKeeper, master nodes, or shard rebalancers.