What does it actually take to build production React Native apps in 2026, and where does Expo fit in?

In this episode of Señors at Scale, Dan sits down with Kadi Kraman, software developer at Expo, who has spent over six years in the React Native ecosystem, wearing every hat from IC to director. Kadi shares the story of how she went from writing C++ in a maths degree to becoming one of the early React Native engineers at Formidable, and eventually joining Expo to work on the platform itself.

We dig into what makes React Native genuinely competitive with native iOS and Android development today, why Expo Go is now just for prototyping, how EAS workflows and fingerprint-based repacks dramatically speed up CI, the real story on OTA updates (and where the legal gray area sits), and what's still missing from the ecosystem. Kadi also gives a rare look at the new Expo agent for vibe-coding mobile apps, the case for React Native brownfield, and her honest take on Lynx as competition.

Key Topics:

- Why React Native + Expo is faster than native Xcode/Android Studio workflows

- The mental shift from web to native (display points, gestures, pixel density)

- Expo Go vs development builds, and why the recommendation has changed

- EAS workflows, repack jobs, and project fingerprints

- React Native performance, list rendering, and the React Compiler

- OTA updates: when to use them, when not to, and what the stores actually allow

- Debugging strategies (expo-doctor, native logs, AI-assisted log analysis)

- Brownfield React Native and embedding RN screens into existing native apps

- Lynx, competition, and the future of cross-platform mobile

- Career advice on imposter syndrome, applying anyway, and finding talk topics

GUEST: Kadi Kraman, Software Developer at Expo

💼 LinkedIn: https://www.linkedin.com/in/kadikraman/

🐦 Twitter/X: https://x.com/kadikraman

🐙 GitHub: https://github.com/kadikraman

🌐 Website: https://kadikraman.com/

FOLLOW & SUBSCRIBE

🎙️ Podcast: https://neciudan.dev/senors-at-scale

📩 Newsletter: https://neciudan.dev/subscribe

💼 LinkedIn (Show): https://www.linkedin.com/company/senors-scale/

💼 LinkedIn (Dan): https://www.linkedin.com/in/neciudan

📸 Instagram (Show): https://www.instagram.com/senorsatscale/

📸 Instagram (Dan): https://www.instagram.com/neciudev

ADDITIONAL RESOURCES

- Expo: https://expo.dev/

- Kadi's "From Web to Native with React" blog post: https://expo.dev/blog

- EAS Workflows: https://docs.expo.dev/eas-workflows/get-started/

- Expo Doctor: https://docs.expo.dev/more/expo-cli/#expo-doctor

- Expo Fetch (streaming support): https://docs.expo.dev/versions/latest/sdk/expo/

#ReactNative #Expo #MobileDevelopment #JavaScript #iOS #Android #EAS #ExpoRouter #SoftwareEngineering #SeñorsAtScale

💬 What's your biggest pain point building React Native apps today, and have EAS workflows changed your CI setup?

Can you really run state-of-the-art machine learning models directly in the browser, with no server, no API calls, and full privacy by default?

In this episode, Nico Martin, Open Source Machine Learning Engineer at Hugging Face and Google Developer Expert in AI and Web Technologies, walks through how Transformers.js makes on-device AI a reality. Nico's journey is anything but conventional. He started as a ski and windsurf instructor, taught himself web development on the side, spent years as a freelancer (including five at a bank building e-banking front ends), and recently landed what he calls his dream job at Hugging Face.

We unpack what Hugging Face actually is (the GitHub for machine learning), how Transformers.js brings the Python Transformers API to the browser, and the real engineering challenges of running models on whatever hardware your users happen to have. Nico explains quantization, ONNX as the standard for portable model architectures, the role of tokenizers, how text becomes tensors, and why WebGPU matters for running larger models client-side.

We also dig into the bigger picture: privacy-preserving AI, the difference between open weights and truly open source models, agents and MCP, and what front-end developers should actually learn to stay relevant in an AI-first world.

Key Topics:

- What Hugging Face is and the role of the Hub, Transformers, and Diffusers

- Transformers.js: bringing Python Transformers API to JavaScript and the browser

- The biggest challenge of browser ML: running on unknown client hardware

- Quantization explained (Q4, 4-bit vs 16/32-bit) and how it compresses models

- ONNX and ONNX Runtime Web: the standard for portable model architectures

- Open weights vs open source models and why the distinction matters

- Tokenizers, token IDs, and why each model needs its own tokenizer

- From text to tensors: pre-processing, inference, and post-processing

- Text embeddings explained through a simple animal feature analogy

- WebGPU and what it unlocks for in-browser inference

- Agents, tool calling, MCP, and how context windows get consumed

- Advice for developers who want to break into AI and ML engineering

🔗 FOLLOW NICO

💼 LinkedIn: https://www.linkedin.com/in/nicodotdev/

🐦 X/Twitter: https://twitter.com/nic_o_martin

🦋 Bluesky: https://bsky.app/profile/nico.dev

🐙 GitHub: https://github.com/nico-martin

🌐 Website: https://nico.dev

🎙️ FOLLOW & SUBSCRIBE

📸 Instagram: https://www.instagram.com/senorsatscale/

📸 Instagram: https://www.instagram.com/neciudev

🎙 Podcast URL: https://neciudan.dev/senors-at-scale

📬 Newsletter: https://neciudan.dev/subscribe

💼 LinkedIn: https://www.linkedin.com/in/neciudan

💼 LinkedIn: https://www.linkedin.com/company/senors-scale/

📚 ADDITIONAL RESOURCES

- Transformers.js: https://huggingface.co/docs/transformers.js

- Hugging Face: https://huggingface.co

- ONNX: https://onnx.ai

- ONNX Runtime: https://onnxruntime.ai

- WebGPU: https://www.w3.org/TR/webgpu/

- Utopia for Realists by Rutger Bregman

#MachineLearning #AI #HuggingFace #TransformersJS #WebML #OnDeviceAI #WebGPU #ONNX #JavaScript #Frontend #WebDev #SenorsAtScale #OpenSource

💬 Would you trust on-device AI over cloud-based models for sensitive data? Share your thoughts in the comments!

What does it actually take to scale a frontend from 15 people in a converted flat to a 1,800-person unicorn, and then migrate the whole thing to microfrontends without breaking anyone's week?

In this episode, Dan sits down with Giorgio Polvara, Staff Engineer at Perk (formerly TravelPerk) and the original creator of @testing-library/user-event (1M+ weekly npm downloads). Giorgio joined TravelPerk as employee #15, set up the frontend foundations that still power the product today, left to try engineering management at Toptal, realized he missed building, and came back as Staff.

They get into the microfrontend migration that replaced a monolithic React app with vertically-split single-page apps served at the infrastructure layer, the rebrand that changed the name, domain, logo, and colors simultaneously, and the philosophy that ties it all together: you're not building features, you're improving a system that happens to produce features.

Key Topics:

- Scaling a frontend team from 7 engineers to a full platform tribe

- Why 20% refactoring time is the wrong model

- Monolith to microfrontends: SingleSPA vs the vertical-split architecture they built

- Managing shared dependencies with pnpm, Syncpack, and Vite plugin packages

- Contract testing with Pact vs runtime schema validation with Zod

- Rebranding an entire product behind a feature flag, without leaking the design

- Why Giorgio tried engineering management and went back to IC

- Staff engineer advice: propose five solutions, expect one to land

🔗 FOLLOW GIORGIO

💼 LinkedIn: https://www.linkedin.com/in/polvara

🐙 GitHub: https://github.com/Gpx

🌐 npm: https://www.npmjs.com/package/@testing-library/user-event

🎙️ FOLLOW & SUBSCRIBE

📸 Instagram: https://www.instagram.com/senorsatscale/

📸 Instagram: https://www.instagram.com/neciudev

🎙 Podcast URL: https://neciudan.dev/senors-at-scale

📬 Newsletter: https://neciudan.dev/subscribe

💼 LinkedIn: https://www.linkedin.com/in/neciudan

💼 LinkedIn: https://www.linkedin.com/company/senors-scale/

📚 ADDITIONAL RESOURCES

- A Philosophy of Software Design by John Ousterhout

- Out of the Tar Pit (Moseley & Marks)

- No Silver Bullet (Fred Brooks)

- @testing-library/user-event: https://www.npmjs.com/package/@testing-library/user-event

- SingleSPA: https://single-spa.js.org

- Vite: https://vitejs.dev

- Pact (contract testing): https://pact.io

- Zod: https://zod.dev

#staffengineer #microfrontends #frontendarchitecture #perk #travelperk #reactjs #softwarearchitecture #engineeringleadership #devtools #softwaredesign #senorsatscale

💬 How does your team handle the tension between shipping features and keeping the system healthy? Drop a comment 👇