Projects sharing features with StreetComplete

Mapbox GL JS is a WebGL map rendering engine and interactive web map framework used to render vector tiles, raster imagery, and 3D terrain in the browser. It functions as a vector tile map library and geospatial data visualization tool, employing GPU-accelerated shaders to transform geospatial data into interactive maps. The project distinguishes itself through the integration of custom WebGL layers directly into the rendering pipeline and the use of data-driven expressions to map feature properties to visual attributes. It supports specialized data loading via PMTiles and provides offline ma

H3 is an open-source library that provides a hierarchical hexagonal grid system for geospatial indexing. It projects the Earth onto an icosahedron and tiles each face with hexagons to minimize distortion, then encodes each hexagon as a 64-bit integer that stores its resolution and position in the hierarchy. This integer encoding enables fast bitwise operations for grid navigation and spatial analysis. The library offers a comprehensive set of grid topology algorithms for computing neighbor relationships, distances, and paths between cells directly on the hexagonal grid without geographic coor

Loro is a conflict-free replicated data type (CRDT) framework and collaborative state engine designed for building real-time collaborative applications. It provides a distributed data synchronizer that enables multiple users to edit shared documents and complex nested structures—such as maps, lists, trees, and counters—with automatic state convergence without requiring a central server. The project distinguishes itself through a versioned document store that supports branching, forking, and merging via a directed acyclic graph of causal operation history. It enables advanced version control c

OpenAddresses is an open-source geospatial data aggregator and directory that collects public domain and open-license address, parcel, and building datasets from governments and organizations worldwide. It functions as a global index and data warehouse for locating and distributing free geospatial records. The project operates a normalization pipeline that cleans and standardizes diverse source formats into a consistent global coordinate and attribute schema. This process includes a crowdsourced curation pipeline and programmatic quality validation to verify the spatial accuracy and formattin

This project is a reference library of architectural blueprints, study materials, and design patterns for building scalable, high-availability distributed systems. It serves as a technical guide for scalability engineering, providing structural solutions for common engineering challenges. The repository focuses on distributed systems design, covering essential patterns for data replication, consensus algorithms, and transaction management. It distinguishes itself by offering detailed blueprints for specialized domains, including real-time data streaming, large-scale data storage, and high-ava

This project is a memory-safe library implemented in Rust that provides a high-performance engine for managing shared, distributed data states. It functions as a conflict-free replicated data type implementation, enabling real-time collaborative editing and state synchronization across distributed systems without the need for a central server or manual conflict resolution. The library distinguishes itself through a cross-language binding framework that allows native applications in environments like Python, Swift, and WebAssembly to interact with the same shared data protocol. It utilizes a c

Tile38 is an in-memory geospatial database that uses the Redis protocol for communication and query execution. It serves as a distributed spatial store for points and polygons, featuring high availability through leader-follower replication and disk-based persistence. The system includes a real-time geofencing engine that monitors virtual geographic boundaries and triggers webhooks when objects enter or exit specified areas. It further distinguishes itself with an embedded Lua scripting engine for server-side data transformations and a built-in vector tile server for efficient map visualizati

cr-sqlite is a multi-master database replication system that uses conflict-free replicated data types to ensure eventual consistency across distributed nodes. It provides the core capabilities for offline-first data synchronization, allowing multiple database instances to merge concurrent updates and reach a consistent state. The project distinguishes itself through a combination of CRDT-based data replication and a WASM-based database engine, enabling full SQL execution and state persistence within web browsers. It supports peer-to-peer replication and cross-tab synchronization, utilizing ca

ShareJS is a collaborative document database and synchronization engine designed for real-time shared state management. It provides an operational transform sync engine to enable simultaneous editing of plain-text and JSON data, and a RESTful synchronization API for managing document states via HTTP. The system features an offline-first data sync layer that queues local modifications while disconnected and automatically pushes edits upon reconnection. It also includes a middleware access control layer that intercepts database requests to enforce security policies and perform request rewriting

GeoPandas is a Python library that extends pandas with native support for geospatial data. It treats geographic geometries—points, lines, and polygons—as a first-class column type within DataFrames, enabling users to store, manipulate, and analyze vector spatial data alongside traditional tabular attributes. The library is built on top of proven geospatial components: it uses Shapely for all geometric operations, Fiona and GDAL for reading and writing standard spatial file formats, PyProj for coordinate reprojection, and an R‑tree spatial index (from Shapely) to accelerate spatial queries. Wh

OsmAnd is a mobile navigation application and vector map viewer that uses OpenStreetMap data to provide offline map access, turn-by-turn routing, and geospatial tools. It functions as a mobile routing engine and a GPX track recorder, allowing users to navigate and record movement without an active internet connection. The project integrates a mobile interface for contributing to the OpenStreetMap project, enabling users to report map errors and add new points of interest directly from their devices. It also includes a system for visualizing satellite imagery and custom tile overlays on top of

Livestore is a reactive state management framework that utilizes a local SQLite database to store and synchronize application data. It provides an event-sourced state store that processes typed events through materializer functions to derive and persist application state. The framework implements offline-first data synchronization using a push-pull engine and append-only event logs to maintain consistency between clients and servers. It includes a real-time presence system for tracking user activity and shared session status across connected clients. The system covers a broad capability surf

Sidekiq is a background job processor and queue manager for Ruby that uses Redis to manage asynchronous tasks. It functions as a distributed task scheduler capable of handling periodic, delayed, and recurring jobs across a cluster of worker processes. The project features a job monitoring dashboard and administrative web interface for visualizing system state, tracking worker performance, and managing failed or dead jobs. It provides a distributed rate limiter to control execution frequency across multiple processes. The framework covers a broad range of operational capabilities, including j

This project provides a collection of conflict-free replicated data types implemented in Rust, designed to enable deterministic state synchronization across distributed systems. It functions as a framework for maintaining data consistency in decentralized environments where central coordination is absent. The library facilitates distributed state synchronization by tracking causal context and unique actor identifiers for every participant. This approach allows the system to resolve concurrent modifications through mathematical lattice structures, ensuring that all replicas converge to the sam

dtale is a web-based interactive grid and visualizer for pandas dataframes, designed as an exploratory data analysis tool. It provides a browser-based interface for analyzing tabular data structures, allowing users to calculate statistics, detect outliers, and compute correlations without writing manual code. The project functions as an embedded data viewer that can be integrated into web applications via iframes or custom routes, with specific support for Django, Flask, and Streamlit. It enables the exploration of datasets through a combination of an interactive data grid and a data visualiz

This is an interactive notebook-based course that teaches machine learning from Python fundamentals through deep learning and natural language processing. It uses real datasets and multiple frameworks within a structured, hands-on curriculum that combines concise explanations with executable code cells, built-in datasets, and embedded exercise checkpoints. Learning progresses through data preparation and exploration, classical machine learning workflows, computer vision with convolutional neural networks, and natural language processing with deep learning, all delivered as a cohesive progressi

This project is a compatibility layer and abstraction library for building native C++ addons for Node.js. It provides a consistent C++ API that allows a single codebase to compile against multiple versions of the V8 JavaScript engine by hiding version-specific differences behind macros and inline functions. The toolkit differentiates itself through specialized wrappers and managers, including a monadic wrapper for handles to avoid explicit null checks, a persistent reference manager for objects that must survive handle scope disposal, and a buffer abstraction API for version-compatible memory

H2 is a JDBC-compliant relational database management system written in Java. It functions as an embeddable SQL database that can run directly within an application process to remove network latency, or as an in-memory database for high-performance volatile storage. It also includes a web-based console for executing SQL commands and administering schemas. The system is characterized by its flexible deployment modes, including a standalone server mode for remote TCP/IP access and a mixed mode for simultaneous local and remote connectivity. It features a dialect emulation layer and compatibilit

Hocuspocus is a backend framework designed to facilitate real-time collaborative editing and state synchronization in web applications. It functions as a server-side infrastructure that manages persistent WebSocket connections, enabling multiple users to edit shared documents simultaneously while maintaining data consistency through a conflict-free replicated data type engine. The platform distinguishes itself through a modular, middleware-driven architecture that allows developers to intercept document lifecycle events, enforce custom access control policies, and integrate external services.

sigma.js is a JavaScript graph visualization library and WebGL network renderer designed for drawing large-scale network graphs in web browsers. It functions as a high-performance engine capable of rendering network structures containing thousands of nodes and edges interactively. The library provides a customizable graph engine that allows for the creation of specialized visualizations using low-level graphics primitives and custom drawing layers. It supports the rendering of diverse node shapes, such as images or piecharts, and enables the integration of graph visualizations as overlays on

Books is double-entry accounting software designed for recording business transactions and managing a general ledger. It functions as an invoicing and billing platform to track accounts payable and receivable, and as a financial reporting tool for generating balance sheets and profit and loss statements. The application is built as an offline-first bookkeeping system that stores data locally during internet outages and synchronizes changes once connectivity is restored. It also includes a retail point of sale system to process immediate sales and record inventory movements. The software cove

This project is an interactive educational platform and comprehensive curriculum designed to teach developers how to build, query, and integrate GraphQL APIs into full-stack applications. It provides a structured learning environment for mastering core concepts such as schema design, query execution, and the implementation of data-driven interfaces. The platform distinguishes itself by focusing on the practical application of real-time data synchronization and backend architecture. It guides users through the process of connecting frontend frameworks to relational databases, implementing role

Memgraph is an in-memory, distributed graph database designed for high-performance labeled property graph management. It utilizes a Cypher query engine for declarative data retrieval and manipulation, providing a scalable knowledge graph backend that integrates vector search and graph traversals. The system distinguishes itself as a real-time graph analytics platform, employing native C++ and CUDA implementations to execute complex network analysis and dynamic community detection on streaming data. It provides specialized support for AI integration, including GraphRAG capabilities, the constr

This project is a JavaScript library and SDK used to integrate web and mobile applications with cloud services. It serves as a bridge to backend providers for user authentication, binary object storage, and real-time data synchronization. The library provides a unified interface for managing cloud identity and access, executing queries and mutations against GraphQL endpoints, and consuming REST APIs with secure request signing. It also includes tools for accessing machine learning services for natural language processing and computer vision. Broad capability areas include offline-first data

Liveblocks is a realtime collaboration infrastructure platform that synchronizes application state, documents, and user presence across multiple participants using conflict-free replicated data types. It provides a managed backend for collaborative text editors, threaded commenting and annotation systems, in-app notifications, and AI copilot deployment, all built on a WebSocket transport layer with server-side room management APIs. The platform distinguishes itself through a headless component primitive system that exposes unstyled React hooks and composable building blocks, allowing develope

rqlite is a distributed relational database that replicates SQLite data across a cluster using the Raft consensus algorithm. It functions as a fault-tolerant storage system that provides high availability and a web API for executing SQL queries and managing relational data without requiring native database drivers. The system distinguishes itself by using an HTTP SQL interface to expose database operations and cluster management. It features a real-time change data capture stream that pushes database mutations to external HTTP endpoints via webhooks and supports the scaling of read throughput

Synapse is a Matrix homeserver implementation that provides the infrastructure for decentralized, real-time communication and messaging. It functions as a federated chat server that synchronizes room data and event streams across independent server instances to enable cross-domain interoperability. The server utilizes a hybrid core that integrates performance-critical logic in Rust with a Python orchestration layer. It employs a PostgreSQL relational database for persisting user accounts and conversation history, and uses a Redis-based messaging system to distribute tasks across horizontal wo