Open-source alternatives to Toshi

Elasticsearch is a distributed search engine and NoSQL document store designed for full-text search and real-time data retrieval. It functions as a RESTful data indexer and vector database, allowing for the storage and management of structured JSON documents across multiple nodes. The system distinguishes itself through its ability to serve as a log analytics platform for monitoring system health and security events. It incorporates vector search implementation using mathematical embeddings to support generative AI and augmented generation applications. The platform covers a broad range of c

Wukong is a distributed full-text search engine designed for indexing and retrieving text documents. It functions as a customizable search backend that employs a BM25 relevance ranker to order search results based on term frequency and inverse document frequency. The system includes a specialized Chinese text segmenter to break continuous character strings into meaningful words for accurate indexing and retrieval. To handle large datasets and high request volumes, it utilizes a distributed search index that employs hash-based sharding to split documents across multiple nodes. The engine prov

Manticoresearch is a high-performance search engine and database designed for indexing and retrieving large datasets. It functions as a full-text search engine, a vector search database, and a SQL-based search database, providing a distributed search cluster architecture. The system provides an alternative to the Elasticsearch stack, offering a compatible API for indexing and searching structured and unstructured data. It distinguishes itself by supporting multiple retrieval methods, including vector matching for similarity search, geospatial queries, and traditional full-text ranking. The p

Lnx is a high-performance search engine and indexing database designed for managing large datasets. It provides a scalable infrastructure for full-text retrieval, allowing applications to process and query structured data with consistent responsiveness. The platform distinguishes itself through a schema-driven approach to data ingestion, which enforces structured field definitions to optimize storage and query precision. It incorporates advanced search capabilities, including fuzzy matching, spell correction, and similarity-based content recommendations, to ensure accurate results even with i

This project is a full text search engine and enterprise search infrastructure designed for indexing and retrieving large sets of documents. It provides a comprehensive framework for information discovery using ranked results and linguistic analysis. The system integrates high-dimensional vector similarity search for semantic retrieval alongside traditional full-text capabilities. It distinguishes itself through support for geospatial data retrieval, multilingual text processing, and a search suggestion workflow that includes typo-tolerant query completion and spellchecking. The platform cov

RediSearch is a Redis module that adds secondary indexing, full-text search, aggregation, and vector similarity search directly into the in-memory data store. It operates as an in-process search engine, extending the core key-value store with capabilities for indexing hash and JSON documents, enabling fast field-level lookups beyond primary key access. The module provides a full-text search engine built on inverted indexes, supporting stemming, fuzzy matching, and relevance scoring via tf-idf. It also includes a vector similarity search engine using a Hierarchical Navigable Small World graph

Quickwit is a cloud-native, distributed search engine designed for observability data such as logs, traces, and metrics. It functions as an observability backend that decouples compute from storage by persisting indices directly in S3-compatible cloud object stores. The system is distinguished by its compatibility with the Elasticsearch REST API, allowing it to integrate with existing clients and log shippers without reconfiguration. It also serves as an OpenTelemetry data indexer, ingesting technical data via the OpenTelemetry Protocol using gRPC and HTTP. The engine utilizes a hybrid of co

Qdrant is a high-performance vector similarity database designed to store, index, and search high-dimensional vectors alongside structured metadata. It functions as a distributed search engine that manages large-scale data clusters, providing low-latency retrieval and complex filtering capabilities. The system is built to serve as a specialized middleware layer, connecting machine learning pipelines and AI agents to persistent storage for intelligent information retrieval and recommendation tasks. The platform distinguishes itself through advanced retrieval techniques, including support for h

OpenGrok is a Java-based source code search engine and indexer designed to process large source trees and binaries into a searchable index. It functions as a version control browser, allowing for the exploration and searching of revision histories integrated with version control systems. The system provides symbol-based cross-referencing to link code definitions and usages, enabling navigation across a codebase. It utilizes an inverted-index search engine to perform full-text retrieval of source code. The application supports periodic source synchronization and reindexing to keep local data

Sonic is a high-performance, lightweight search backend designed to provide real-time full-text search and autocomplete capabilities for applications. It functions as a persistent indexing server that maps text terms to object identifiers, allowing developers to integrate rapid search functionality without storing raw document content directly within the search engine. The system distinguishes itself through a specialized graph-based index that enables real-time word prediction and typo correction. Communication is handled via a custom, low-latency binary protocol over raw TCP sockets, which

Mailpile is an encrypted email client and high-volume mail indexer that provides a web-based portal for managing electronic mail. It functions as a private email management system designed to protect user privacy and data control. The project features a search engine optimized for indexing and retrieving large volumes of email on consumer hardware. It includes a Bayesian email filter for automated message classification and tagging. The system supports secure communication through the integration of public-key encryption and signing for sending and receiving messages. Additional capabilities

SQLite is a serverless relational database engine and C-based library that stores data in a single local disk file. It functions as an embedded SQL database, integrating directly into applications without the need for a separate server process. The engine includes specialized capabilities for full-text search indexing and spatial data querying using R-Tree structures for geographic or geometric coordinate ranges. The system provides broad support for SQL data manipulation, database recovery and repair, and change tracking for synchronizing modifications between databases. It also features a

m3 is a distributed time series database designed for high-resolution metrics and high-cardinality data management. It functions as a scalable storage system and a multi-cluster query engine, providing a distributed metrics aggregator capable of downsampling and summarizing data before it is committed to storage. The project distinguishes itself through a coordinated cluster model using etcd for node membership and shard placement. It supports multiple ingestion protocols, including the Prometheus remote write protocol, InfluxDB line protocol, and Graphite Carbon plaintext protocol, and provi

Vespa is a distributed search engine, vector database, and machine learning ranking engine. It serves as an AI search platform designed to handle large-scale document indexing and complex query processing across a cluster of nodes, combining keyword retrieval with high-dimensional embedding storage for semantic similarity search. The platform distinguishes itself by integrating machine learning models directly into the search pipeline to perform real-time inference and ranking. It converts these models into ranking expressions to score and order results based on relevance, while providing a s

This project is a Go client library and API wrapper for interacting with Elasticsearch clusters. It serves as a programmatic interface for managing documents, indices, and cluster health, allowing Go applications to perform search and indexing operations via the REST API. The library functions as a distributed search orchestrator, providing specialized tools for high-throughput data ingestion and cluster administration. It features a buffered bulk processor with exponential backoff retries for optimizing write performance and supports automated index lifecycle transitions and historical data

This project is a comprehensive Java backend engineering guide and technical reference focused on high-concurrency design, distributed systems, and microservices architecture. It provides detailed strategies for decomposing monolithic applications, managing service discovery, and implementing the architectural patterns required for scalable backend environments. The repository distinguishes itself through an extensive collection of big data algorithmic references and database scaling strategies. It covers memory-efficient techniques for analyzing massive datasets, such as Top-K element extrac

Riot is a Go-based distributed search engine and indexing server designed for full-text indexing and retrieval. It functions as a retrieval system that sorts documents by relevance using BM25 ranking algorithms, term frequency, and inverse document frequency. The engine provides specialized support for the Chinese language, featuring concurrent text segmentation and phonetic Pinyin mapping to match romanized input with characters. It utilizes a distributed architecture that employs hash-based index sharding to balance data load and throughput across multiple server nodes. The system covers a

Tantivy is a library for building full-text search engines and indexing frameworks. It provides the core components necessary to organize large collections of text data into searchable structures, enabling the execution of complex queries and the retrieval of information across structured document sets. The engine utilizes an inverted index architecture to map terms to document identifiers, supported by a segment-based storage model that balances search performance with write throughput. It incorporates specialized data structures, including finite state transducers for term dictionaries and

pg_textsearch is a full-text search integration for PostgreSQL that provides large-scale text indexing and BM25 relevance ranking. It implements a scalable indexing architecture that uses a memtable system to spill data to disk segments, allowing for the processing of massive datasets. The project distinguishes itself through support for multilingual search via language-specific partial indexes and the ability to index complex expressions, such as JSONB fields or concatenated columns. It ensures high availability by utilizing PostgreSQL-native streaming replication and write-ahead logs to syn

LevelDB is an embedded database library and persistent storage engine that provides a sorted key-value store. It uses a log-structured merge-tree architecture to map byte arrays to values, running directly within a process to provide storage without the need for a separate server process. The system is distinguished by its use of custom comparison functions to define key ordering, enabling efficient range scans and sequenced lookups. It ensures data reliability through atomic batch execution, consistent snapshot generation, and log-based recovery after failures. The engine covers broad capab

SPTAG is a vector approximate nearest neighbor search library and distributed vector search engine. It provides a large-scale vector index designed to organize and retrieve similar vectors from massive datasets using high-performance similarity search and proximity queries. The system functions as a dynamic vector index manager, supporting incremental updates, insertions, and deletions of vectors without requiring a full index rebuild. It scales search operations across multiple machines to handle large-scale datasets and high volumes of online requests through distributed search request hand

This project is a programmatic client for managing the lifecycle of documents within a distributed JSON search engine. It provides an Elasticsearch search client for indexing documents and performing complex queries, alongside a low-level client that acts as a flexible wrapper for sending raw HTTP requests to a cluster. The client features a fluent request builder that maps typed requests to REST API endpoints and a generic mapping layer to transform JSON responses into strongly typed objects. It employs a pluggable serialization mechanism to decouple the request-response lifecycle from speci

Bolt is a single-file embedded key-value store for Go applications. It is an ACID transactional database that organizes data in B+trees on disk to provide efficient sorted key retrieval and range scans. The system uses a memory-mapped model to map the database file directly into the process address space for fast random-access reads. The project distinguishes itself through a multi-version concurrency control architecture that allows multiple simultaneous readers to access a consistent snapshot of data without blocking a writer. It employs a single-writer multi-reader locking model and uses a

Excelize is a library for reading and writing spreadsheet files in the Office Open XML format. It provides a comprehensive suite of tools for programmatically creating, modifying, and analyzing workbooks, worksheets, and cell data, ensuring compatibility across various office software suites through structured XML serialization. The library distinguishes itself with a built-in formula calculation engine that evaluates complex mathematical and logical expressions directly against workbook data. It also features a memory-mapped streaming architecture, which allows for the efficient processing o

Orama is a search engine and vector database that provides full-text indexing, geospatial calculations, and semantic vector storage. It functions as an LLM retrieval engine designed to provide grounded context to language models for conversational interfaces. The project implements hybrid search by combining dense vector embeddings with inverted keyword indices to retrieve documents based on both semantic meaning and exact text matches. It utilizes a WebAssembly module to execute search logic across different JavaScript environments and platforms. The system covers a broad range of retrieval

Zinc is a high-performance full-text search engine written in Go. It provides a schema-less document index that organizes arbitrary datasets into searchable structures without requiring a predefined data format. The engine features an API compatible with Elasticsearch for indexing and querying data, which facilitates the ingestion of single and bulk records. It is designed as an in-process search engine that embeds indexing and retrieval logic within a single binary to operate with minimal system resource overhead. The system includes a built-in web-based management interface for executing s

Bleve is a search indexing engine library written in Go, designed to provide full-text search and document retrieval capabilities for embedded application data. It functions as a framework for indexing structured or unstructured information, allowing developers to build searchable collections that support complex query logic and data analysis. The engine distinguishes itself through a pluggable analysis pipeline that normalizes text before indexing, alongside support for vector similarity search to identify semantically related content. It utilizes finite-state transducer automata for efficie

Kvrocks is a distributed key-value store and Redis-compatible NoSQL database. It utilizes a RocksDB storage engine to provide disk-based persistence, allowing for high-capacity data storage with reduced memory costs compared to in-memory systems. The system functions as a vector database and full-text search engine, supporting nearest-neighbor searches on vector embeddings and complex document queries via text matching. It employs a proxyless cluster architecture with slot-based routing to distribute data and scale capacity across multiple nodes. The platform covers a wide range of data mana

Isar is a type-safe, ACID-compliant local NoSQL document store designed for high-performance data storage and retrieval. It functions as an embedded database engine that persists large datasets on-device while ensuring transactional integrity through automatic rollbacks of failed write operations. The project distinguishes itself by validating database queries at compile time using static typing to prevent runtime errors. It incorporates a full-text search engine with specialized indexing for efficient keyword and phrase matching and utilizes parallel execution across multiple isolates to pre

dn is a self-hosted personal web archiving system that automatically intercepts and stores web pages on a local device. It uses a proxy-based request interception model to capture browser traffic and save content for offline access without an internet connection. The system features a local full-text search engine that indexes all saved page content for information retrieval across the collection. It includes a dedicated browser interface that simulates online connectivity to serve archived files, mimicking the original live web environment. Administrative control is provided through a web-b