Directory

Python workflow orchestrator for scheduling and monitoring DAGs of tasks, with hundreds of provider packages and managed offerings from several clouds

Extensible Rust query engine built on Apache Arrow offering SQL and DataFrame APIs, Parquet readers and an optimizer for embedding in data systems

Distributed event streaming platform with durable, partitioned, replayable logs, Kafka Connect connectors and Kafka Streams processing

Distributed data processing engine with DataFrame and SQL APIs in Python, Scala, Java and R, plus structured streaming and MLlib

Self-hosted, open-source web archiving tool that saves URLs as HTML, PDF, screenshot, WARC, readable text and media snapshots with a web UI and CLI

Webrecorder's browser-based web archiving system, available hosted or self-hosted, that crawls sites with real browsers into signed WACZ files replayable with ReplayWeb.page

Open-source embedding database with a minimal Python and JavaScript API, usable in-process, as a server or through Chroma Cloud

Open-source columnar OLAP database server for fast aggregations over billions of rows, with MergeTree storage, SQL and a managed ClickHouse Cloud

Open-source crawling and scraping library for Node.js/TypeScript and Python that unifies HTTP and headless-browser crawlers with queues, proxies, fingerprints and storage

Asset-oriented Python orchestrator that models pipelines as software-defined data assets with lineage, checks and a hosted Dagster+ option

TypeScript ORM with SQL-like query builder, schema defined in code, migrations through Drizzle Kit, and support for PostgreSQL, MySQL and SQLite drivers

In-process analytical SQL database that queries Parquet, CSV and Arrow data directly from Python, R, Node or the CLI

Python data-quality framework that declares Expectations about datasets, validates them against pandas, Spark or SQL sources and produces Data Docs

Embedded property-graph database with Cypher, vector and full-text search; MIT-licensed but archived in October 2025 after the company was acquired

Reactive Python notebook stored as a plain .py file that re-runs dependent cells automatically and doubles as a script or web app

Lightweight Go messaging system with core pub/sub and request-reply plus JetStream persistence, key-value and object stores; a CNCF project

Microsoft's browser automation and end-to-end testing framework driving Chromium, Firefox and WebKit from one API in TypeScript, Python, Java and .NET

Spatial extension for PostgreSQL adding geometry, geography and raster types with indexing and hundreds of SQL functions

Open-source object-relational database server with a large extension ecosystem (PostGIS, pgvector, TimescaleDB) and broad SQL coverage

Python workflow orchestration library and server where decorated functions become observable, retryable flows, with Prefect Cloud as hosted option

TypeScript ORM with a declarative schema language, generated type-safe client and migration tooling, from the company that also offers Prisma Postgres and related hosted services

Open-source computational notebook ecosystem: the .ipynb format, kernels for Python, R and Julia, JupyterLab and Notebook interfaces and JupyterHub

Open-source scientific publishing system from Posit that renders Markdown with executable Python, R, Julia or Observable code to HTML, PDF, Word, slides, websites and books via Pandoc

Open-source message broker in Erlang supporting AMQP 0-9-1 and 1.0, MQTT, STOMP and Streams, with routing, acknowledgements and quorum queues