Inside Facebook Mobile

It's not just Not Invented Here Syndrome. Some technologies like CSS simply don't scale if you're building some of the largest websites on the planet with thousands of engineers committing to the same code base every day. StyleX is Meta's open-source solution for CSS at scale and allows atomic styling of components while deduplicating definitions for bundle size and exposing a delightfully simple API for developers.  Tune in to learn from Melissa, one of the StyleX maintainers how Open Source has acted as a force multiplier for the project, how interacting with other large companies adopting StyleX has been, and much more! Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don't forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links How AI Is Transforming the Adoption of Secure-by-Default Mobile Frameworks: https://engineerin

You've likely heard of Meta Ray-Ban Display by now — but what's it actually like to work on it? In this episode, Pascal talks to Kenan and Emanuel about the exciting features of Meta's First-Gen Display Glasses and Neural Wristband, the engineering and product challenges they encountered during development, and their vision for future generations of these devices.  Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don't forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Pyrefly Beta: https://pyrefly.org/blog/pyrefly-beta/ Pyrefly and Pydantic: https://pyrefly.org/blog/pyrefly-pydantic/  Meta Ray-Ban Display: https://www.meta.com/gb/ai-glasses/meta-ray-ban-display/  Timestamps Intro 0:06 Introduction Kenan 1:35 Introduction Emanuel 5:03 Roles and responsibilities 8:07 What is Meta Ray-Ban Display? 11:13 M

In this episode, Pascal talks to Dharmesh J. (DJ) and Lisa about the vision for the open, scalable future of networking hardware for AI and to break down Meta's big announcements from the 2025 Open Compute Project (OCP) Summit. We dive into the OCP ecosystem, explore how AI is used to enhance our carbon modeling, and share our progress toward achieving Net Zero emissions across all scopes by 2030. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don't forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links OCP: https://www.opencompute.org/ OCP Summit 2025: https://engineering.fb.com/2025/10/13/data-infrastructure/ocp-summit-2025-the-open-future-of-networking-hardware-for-ai/  How Meta Is Leveraging AI To Improve the Quality of Scope 3 Emission Estimates for IT Hardware: https://engineering.fb.com/2025/10/14/data-cente

How do you keep Android build times under control when your codebase spans tens of thousands of modules and millions of lines of Kotlin? In this episode, Pascal talks with Iveta, Navid, and Joshua from Meta’s Android Developer Experience team about the technical strategies that help Meta’s engineers stay productive at scale. We discuss approaches like source-only ABIs and incremental compilation – clever solutions that have helped us tackle the challenges of building fast in a monorepo, as well as what you can do to keep your builds fast with Buck2. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Timestamps Intro 0:06 Introducing Iveta 2:09 Introducing Joshua 3:29 Introducing Navid 4:00 Android DevX Team 4:36 The challenges of build speed 6:28 Buck2 and Andr

Creating 3D assets can be daunting, but does it have to be? Mahima and Rakesh are on a quest to democratize 3D content creation with AssetGen, a foundation model for 3D. They discuss the challenges of training such a model given the scarcity of available data and how large language models have unlocked key solutions. As if that weren't enough, they're also tackling the ambitious goal of generating entire worlds from a simple prompt. Tune in to learn more! Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_, @passy.bsky.social). Fancy working with us? Check out https://www.metacareers.com/. Links Horizon Worlds Desktop Editor: https://developers.meta.com/horizon-worlds/advanced-tools  Horizon Worlds Studio: https://developers.meta.com/horizon-worlds/studio/application Meta Ray-Ban Display: https://www.meta.com/gb/ai-glasses/meta-ray-b

To not leave you without an episode for August, Pascal brings you an episode from the Archive. Back in August 2023 for Episode 55, Pascal spoke with Katherine and returning guest Dustin, two software engineers at Meta about how to ship code at Meta. Why do we have a monorepo? Why and how do we do pre-commit code review? What does our CI infrastructure look like? Get the answers to these questions and many more in this episode of the Meta Tech Podcast. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links The evolution of Facebook’s iOS app architecture - Engineering At Meta: https://engineering.fb.com/2023/02/06/ios/facebook-ios-app-architecture/ Episode 47: Source control at Meta - https://pca.st/episode/429e9f38-6537-43e3-b929-fbeeda326ed5 Timestamps Intro 0:

Join Pascal as he explores the groundbreaking world of generic neuromotor interfaces with Jesse, Lauren, and Sean. Discover how these technologies enable control of devices with just a flick of the wrist or even a simple intention to move. We'll discuss the role of AI in eliminating the need for personalised training, the differences between non-invasive interfaces and their predecessors, and the exciting implications for accessibility. Don't miss this deep dive into the future of human-computer interaction. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Timestamps Intro 0:06 Jesse introduction 1:29 Lauren introduction 2:42 Sean introduction 3:29 Team's mission statement 3:49 What's a neuromotor interface? 4:24 Paper overview 5:29 Non-invasive interfaces

What happens when decades-old C code, powering billions of daily messages, starts to slow down innovation? In this episode, we talk to Meta engineers Elaine and Buping, who are in the midst of a bold, incremental rewrite of one of our core messaging libraries—in Rust. Neither came into the project as Rust experts, but both saw a chance to improve not just performance, but developer experience across the board. We dig into the technical and human sides of the project: why they took it on, how they’re approaching it without a guaranteed finish line, and what it means to optimise for something as intangible (yet vital) as developer happiness. If you’ve ever wrestled with legacy code or wondered what it takes to modernise systems at massive scale, this one’s for you. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us?

Pyrefly is a faster, open-source Python type checker written in Rust, succeeding Pyre. But what prompted the rewrite and what besides the language choice ended up making it faster? Host Pascal talks to Maggie, Rebecca and returning guest Neil about the unexpected complexities of building an incremental type checker that scales to mono repositories in episode 75. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Pyrefly: https://pyrefly.org/ Pyre: https://pyre-check.org/  Ruff: https://github.com/astral-sh/ruff  PEP 484: https://peps.python.org/pep-0484/  Timestamps Intro    0:06 Rebecca Introduction    1:45 Maggie Introduction    2:45 Neil (Re-)Introduction    3:12 Team Mission    3:56 History of Typing in Python    4:29 The State of Typed Pyth

To ensure that everyone has access to resilient, high-speed and low-latency connections to Meta services, no matter where in the world they are, Meta makes large-scale investments into subsea cable infrastructure. The recently announced Project Water worth will, Once complete, reach five major continents and span over 50,000 km (longer than the Earth’s circumference), making it the world’s longest subsea cable project using the highest-capacity technology available.  In this episode, host Pascal talks with another Pascal and his colleague Andy who are involved at every stage of these projects and share the surprising challenges one has to deal with when working on the largest subsea cable project in the world. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Projec

Join Pascal and Sabrina on the latest Meta Tech Podcast episode as they discuss the evolution and future of GraphQL. From client-side consistency to innovative APIs, learn how GraphQL is making developers' lives easier and enhancing user experiences. Discover surprising insights into the challenges of building a mobile GraphQL platform and how it's transforming product development at Meta.  Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links GraphQL: https://graphql.org/  Relay: https://relay.dev/  Sabrina at GraphQL Conf 2024: https://www.youtube.com/watch?v=PGBC-0E-kco  Timestamps Intro 0:06 Introduction Sabrina 1:42 Sabrina's team 2:47 What's GraphQL? 3:18 Relay and Mobile GraphQL Clients 4:01 GraphQL Consistency Engine 4:54 Pando Mobile GraphQL

In this episode of the Meta Tech Podcast, host Pascal sits down with Shane, a research scientist at Meta, to explore the cutting-edge research behind Ray-Ban Meta glasses. Shane shares insights from his seven-year journey at Meta, where he focuses on computer vision and multimodal AI within the Wearables AI organization. Tune in to learn how Shane's team is pioneering foundational models for Ray-Ban Meta glasses, tackling unique challenges, and pushing the boundaries of AI-driven innovation. Discover how multimodal AI is transforming user experiences and get a glimpse into the future of wearable technology. Whether you're an engineer, a tech enthusiast, or simply curious about the latest advancements, there is something for everyone in this episode.  Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out htt

How do you translate roughly ten million lines of Java code to Kotlin? Clicking in your the IDE gets pretty repetitive after a while and doesn’t work if you have custom APIs and requirements for null safety. Eve and Jocelyn, two software engineers on the Mobile Infra Codebases Team have taken on this challenge and talk host Pascal through the unexpected difficulties when embarking on the journey to (close to) 100% Kotlin in our Android codebase. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Meta Engineering Blog - Translating Java to Kotlin at Scale: https://engineering.fb.com/2024/12/18/android/translating-java-to-kotlin-at-scale/  Open-source transformations: https://github.com/fbsamples/kotlin_ast_tools  Mobile @Scale Conference recordings: https://www.y

Introducing a new Android UI Framework like Jetpack Compose into an existing app is easy right? Import some AARs and code away. But what if your app has specific performance goals to meet, has existing design components, integrations with navigation and logging frameworks? That is where Summer and her team come in who handle large-scale migrations for Instagram. They aim to provide developers with the best possible experience when working on our code bases, even if that requires some temporary pain on the side of infrastructure teams that have to maintain multiple implementations at once. Why Summer thinks it is worth it, how they approach the rollout of a new framework and so much more is all discussed in episode 70. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links

Do types actually make you more productive or is it just more typing for you to do on the keyboard? That's just one of the questions we managed to answer at least on a small scale with Diff Authoring Time or DAT, here at Meta. Want to know how we leverage metrics to run experiments on productivity in our internal codebase? Tune in to episode 69. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://mastodon.social/@passy, and https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Hack language: https://hacklang.org/  Timestamps Intro 0:06 Henri Intro 1:45 Ian Intro 3:13 Moritz Re-Intro 3:28 DAT Recap 3:48 What is Hack? 4:20 Inner and outer loop 14:13 Experimenting with language features 17:47 Code sharing frameworks at Meta 27:43 Measuring framework productivity 29:01 Will we see more experiments? 34:23 Time savings from co

How do you build your own mixed reality headset from sketch to scale? That's exactly what Alfred Jones, VP of hardware engineering at Meta Reality Labs, discussed with host Pascal. From choosing the right display technology, battery, thermal budget and of course hitting the right price point. How he manages to not fall victim to choice paralysis and so much more in episode 68. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod) or Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Caddy: https://engineering.fb.com/2024/07/18/virtual-reality/caddy-cad-mixed-reality-mr-meta/ Timestamps Intro 0:06 Alfred Introduction 1:40 Who do you work with? 3:23 Decision making frameworks 5:20 Is MR the final destination? 7:19 What makes good passthrough such a challenge? 10:18 How to build your own MR headset 13:51 Hardware design constraints 19:0

At Meta, engineers are our biggest asset which is why we have an entire org tasked with making them as productive as possible. But how do you know if your projects for improving developer experience are actually successful? For any other product, you would run an A/B test but that requires metrics and how do you measure developer productivity? Sarita and Moritz have been working on exactly that with Diff Authoring Time which measures how long it took to submit a change to our codebase. Host Pascal talks to them about the way this is implemented, the challenges and abilities this unlocks. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Twitter (https://twitter.com/metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://twitter.com/passy, https://mastodon.social/@passy, and https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Meta Connect 2024: https://www.meta.com/en-gb/connect/

Bento is Meta’s internal distribution of Jupyter Notebooks, an open-source web-based computing platform. Host Pascal is joined by Steve who worked with his team on building many features on top of Jupyter, including scheduled notebooks, sharing with colleagues and running notebooks without a remote server component by leveraging Webassembly in the browser. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Twitter (https://twitter.com/metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://twitter.com/passy, https://mastodon.social/@passy, and https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Scheduling Jupyter Notebooks at Meta: https://engineering.fb.com/2023/08/29/security/scheduling-jupyter-notebooks-meta/ Serverless Jupyter Notebooks at Meta: https://engineering.fb.com/2024/06/10/data-infrastructure/serverless-jupyter-notebooks-bento-meta/ Jupyter Notebooks: https://jup

We don’t know when but at some point in the future we will face what researchers call a "Quantum Apocalypse". This is when quantum computers will be able to break many of our existing encryption algorithms. To keep Meta’a users safe even from attacks that don’t even exist today, Sheran and Rafael are working on post-quantum-ready encryption. Tune in to learn about the various challenges and trade offs that this work brings with it.   Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Twitter (https://twitter.com/metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://twitter.com/passy, https://mastodon.social/@passy, and https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Post-quantum readiness for TLS at Meta: https://engineering.fb.com/2024/05/22/security/post-quantum-readiness-tls-pqr-meta/  Fizz TLS implementation: https://github.com/facebookincubator/fizz  liboqs: https://

After sitting in one too many Zoom meetings looking at flat images of 3D models, mechanical engineers Ed, Jason, Fan, and Raghavan decided that they could do better, taught themselves how to code and started to build Caddy - a CAD app for mixed reality. Tune in to episode 64 to hear their story. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Twitter (https://twitter.com/metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://twitter.com/passy, https://mastodon.social/@passy, and https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Caddy video: https://heycaddy.net/ Caddy on the Quest Store: https://www.meta.com/en-gb/experiences/24212682218375897/  @Scale conference on YouTube: https://www.youtube.com/channel/UCd9I8ZkgoR1d7GeSj_wi_LQ  MLow @Scale talk: https://www.youtube.com/watch?v=3ypsZUNRjI4 MLow blog post: https://engineering.fb.com/2024/06/13/web/mlow-metas-low-bit