Open-source Coveo alternatives

SWIRL is an AI search and retrieval-augmented generation tool that works without moving your data. Instead of copying content into a vector database, it queries your sources live with each user's own permissions, re-ranks the results, and can generate an answer with citations using the language model of your choice. The Community edition in this repository is released under the Apache-2.0 license.

Connectors reach many business applications, and the project's tagline refers to more than 100 apps. The approach avoids building ETL pipelines, standing up a vector store, or maintaining a second copy of data that needs security and audit controls, since permissions are enforced at the source. The stack is Python and Django, and a Docker quick start gets an instance running in about two minutes.

A separate SWIRL Enterprise edition adds a three-pass reranker, canonical answers, an MCP server for agents, and managed support. The Community edition is free to self-host. It suits IT and data teams wanting enterprise search across many systems while keeping data in place.

Fess is an open-source enterprise search server that you install and run on any platform with a Java runtime. It is built on OpenSearch but does not require prior OpenSearch knowledge, because everything is configured in a browser-based administration interface. It can also serve as a free site search for your own website.

A built-in crawler collects documents from web sites, file systems and data stores such as databases, CSV files, cloud storage and SaaS sources, and handles many formats including Microsoft Office files, PDF and archives. Search supports faceting, sorting and suggestions, results can be filtered by role and permission, and single sign-on works with LDAP, OpenID Connect, SAML, SPNEGO and Microsoft Entra ID. It offers a REST API, text analysis for over 20 languages, plugins, and AI features for RAG and semantic search.

Fess is written in Java and licensed under Apache-2.0. It needs Java 21 or newer for the ZIP, RPM and DEB packages, and Docker images bundle OpenSearch. It suits organizations that want a private, self-managed alternative to Elasticsearch-based setups or Google Site Search.

Trieve is an all-in-one platform that exposes search, recommendations, retrieval-augmented generation (RAG) and analytics through an API. Developers upload content as chunks and then query it with semantic, keyword or hybrid search, without assembling the vector database, embedding and reranking pieces themselves.

Its search features include dense vector search with OpenAI or Jina embeddings stored in Qdrant, typo-tolerant neural sparse search, sub-sentence highlighting, recency biasing, merchandising controls and hybrid search with cross-encoder reranking. A recommendations API finds similar chunks or files, and RAG routes use OpenRouter so you can pick the language model. You can also plug in your own embedding, reranking and LLM models.

Trieve can be self-hosted in your VPC or on-premises, with guides for AWS, GCP, Kubernetes and Docker Compose, and it also offers a hosted sign-up with a free allowance of 1,000 chunks. The backend is Rust with Actix and Diesel on PostgreSQL, with a SolidJS front end, an OpenAPI specification and TypeScript and Python SDKs. It is released under the MIT licence.

Open Semantic Search is a research tool aimed at journalists, researchers and analysts who need to search, browse, analyze and explore large collections of documents, going well beyond simple keyword search. It combines a semantic search engine with a full text mining and text analytics platform.

It includes an ETL framework for processing documents, covering crawling, text extraction, text analysis, named entity recognition for persons, organizations and locations, and OCR for images and embedded images inside PDFs. On top of that data pipeline, it provides metadata management through thesauri and ontologies using the SKOS standard, and search user interfaces and applications supporting full-text search, faceted search, exploratory search and knowledge graph search. Its topics specifically mention OSINT and investigative journalism as use cases.

Open Semantic Search can be built as a Debian or Ubuntu package, as a desktop search appliance for VirtualBox, or as a set of Docker images using the project's docker-compose configuration, which starts all the needed services together. It is written in Shell and Python, documented with MkDocs, and released under the GPL-3.0 license.

OpenSearchServer is enterprise-class search engine software built on Lucene. With its web user interface, crawlers and JSON web service, you can add advanced full-text search to an application quickly. It runs on Linux, Unix, BSD and Windows.

Search functions include phonetic search, boolean queries with a query language, faceted and collapsed results, filters via sub-requests, geolocation, spell-checking, relevance customization and auto-completion suggestions. Indexing supports 18 languages with per-language analyzers, lemmatization, n-grams, synonyms, automatic language recognition, named entity recognition and automatic classification.

It can index HTML, Microsoft Office and OpenOffice documents, PDFs with OCR, RTF, plain text, audio metadata and images through OCR, using web, file system and database crawlers. OpenSearchServer is licensed under Apache-2.0; the README notes a Docker image was still to come, and documentation and binaries are on the project site.