Meta Open Source

The 2026 Python Type System & Tooling Survey is live 📝 No typing experience needed, your perspective as a Python dev matters most. Take a couple minutes to help improve Python typing for all! 👉 https://lnkd.in/eS7tsE4y This survey was developed with support from the Pyrefly team at Meta, the PyCharm team at JetBrains, the Python team at Microsoft, and the typing community on discourse.python.org

🚀 Introducing Astryx from Meta: an open source design system built for how we build now → Astryx Design(astryx.atmeta.com) → GitHub(https://lnkd.in/guzGmttC) Open source is how the best ideas in our industry travel. The tools we reach for every day, like React, StyleX, PyTorch, got better because someone decided to share them, and a community made them stronger. We're excited to introduce Astryx from Meta, an open source design system that's AI fluent and fully customizable without dependencies. It's a complete, production-ready (and growing) toolkit with 150+ accessible components, brand-level theming, dark mode, ready-to-ship templates, and a CLI – all as one cohesive system, built on React and StyleX. Astryx has matured within Meta for the last eight years and powers over 13,000 apps. It’s shaped by the designers, engineers, and product teams who depend on it every day and now, it’s yours, too. Start anywhere, change anything, and ship faster. Most design systems make you choose. Adopt a big company system and you inherit its brand – your app ends up looking like someone else's product. Reach for copy/paste component collections and you get freedom, but every project forks its own snippets with no shared coherence, no upstream fixes, no upgrade path, and accessibility quietly becomes your problem. Astryx is built to end that trade-off. The system controls behavior, accessibility, and quality, while themes control how it looks. You customize at the token level (color, typography, radius, motion), so that you can make it unmistakably yours without starting from scratch and without rewrites. Builders can stop reinventing the basics and start shipping ideas faster. The way we build software is changing, and Astryx is designed for people and the agents building alongside them. Design systems have historically been designed for human consumption but as more code is written by agents, we have to rethink how design systems are structured and the role that they play. Astryx was built ground-up to be AI-operable, opposed to retrofitting existing design systems to play nicely with agent behaviors. It’s an open source design system built for how we build in this new world. Astryx is in Beta and ready for you to build with today. Try it out at Astryx Design(astryx.atmeta.com) and on GitHub(https://lnkd.in/guzGmttC)

Python is the most used programming language at Meta. This year marks our 10th consecutive year as a sponsor of the Python Software Foundation, the organization dedicated to advancing and protecting the language and its community. In this post, we reflect on why we invest in the PSF, and why we believe organizations that depend on Python share a responsibility to support it. Read more: https://lnkd.in/eCANwQv8 #Python #OpenSource #PSF

We’re thrilled to share that Pyrefly, our open source type checker and language server for Python, has officially reached v1.0! This has been a huge team effort. Since our beta release last November, we've shipped over 60 updates, fixed hundreds of bugs, and added features the community has been asking for. Check out our latest video and blog walking through what you can expect from the latest release: Video: https://lnkd.in/erXMweC6 Blog: https://lnkd.in/eGHjgXWx We also want say a huge thank-you to the open-source community for helping us get here. 🙏

The official Python Developers Survey is currently open 📝 🙌 Take the survey now — it takes less than 15 minutes to complete and helps the open source community understand the evolving needs of Python users. The survey is a joint initiative developed by the Python Software Foundation and JetBrains. Link: https://lnkd.in/gM_K7e9S

⚡️OSS Project Spotlight⚡️ Yoga is a cross-platform layout engine that brings Flexbox to any environment—not just the web. Written in C++, it powers the layout for massive frameworks like React Native and Litho, enabling you to build responsive UIs once and run them anywhere. Learn more: https://lnkd.in/eM93dR3i

🔎 Meta Open Source 101🔎 Do you work with survey data that doesn't quite match your target audience? Use Balance, a Python package that adjusts biased data samples (like non-representative surveys) by creating weights to match a target population. Surveys often suffer from selection bias—where the people who respond don't match the general population—but Balance fixes this by fitting weights to your sample using standard statistical methods like Raking, Post-stratification, and Propensity Score weighting (IPW). The workflow is designed to be simple and data-driven: you load your sample and target data, run sample.adjust() to fit weights automatically, and then evaluate the results using sample.covars().plot() to visualize the reduction in bias. Balance is used internally at Meta to ensure accurate insights from user sentiment surveys, empowering developers to use rigorous statistical methodologies without needing a deep background in survey statistics. Learn more at https://lnkd.in/epcqhUXc and read the deep dive here: https://lnkd.in/eN8hqYKb

⚡️OSS Project Spotlight⚡️ Folly is a library of C++ components designed with practicality and efficiency in mind. It complements the standard library with optimized utilities—such as fast synchronization primitives and memory-efficient containers—that power Meta's core infrastructure at scale. Learn more: https://lnkd.in/dt-ZbyeN

🔎 Meta Open Source 101🔎 Need the development speed of a dynamic language but the discipline of a static one? Meet HHVM (HipHop Virtual Machine) and Hack, the engine and language designed to execute PHP code with lightning-fast performance using Just-In-Time (JIT) compilation. Hack introduces "gradual typing," allowing you to mix dynamic and static typing seamlessly. This means you can write code quickly like in PHP, but use Hack's type checker (hh_client) to catch errors instantly before you even run the program—preventing crashes in production. Running a script is simple. Instead of the standard PHP engine, you use the HHVM CLI. To run a file, simply use hhvm script.hack, or to start a web server on port 8080, run hhvm -m server -p 8080. HHVM powers the massive web tier at Meta, handling billions of requests, and evolved to support the specific needs of modern web development at extreme scale. Learn more at https://hhvm.com/ and read the engineering deep dive here: https://lnkd.in/ecnQy9kn

⚡️OSS Project Spotlight⚡️ Lexical is an extensible text editor framework designed for reliability, accessibility, and performance. It provides a powerful, framework-agnostic engine for building sophisticated text editing experiences on both the web and iOS. Learn more: https://lexical.dev/