Micro Frontends at Scale with Luca Mezzalira (O’Reilly Author and Principal Architect at AWS)

In this episode of Señors @ Scale, Dan sits down with Luca Mezzalira, Principal Serverless Specialist at AWS and author of Building Micro-Frontends, for a deep and highly practical look at scaling frontend architectures for hundreds of developers.

Luca shares the real story behind how micro-frontends were born — from his early experiments at DAZN trying to scale a live sports platform across 40 devices and 500+ engineers, to pioneering techniques that cut app startup times from 40 seconds to 12.

We break down how distributed frontends actually work:
How to design stable application shells with zero global state,
How to compose independently deployed views without iframes, and how guardrails like bundle-size budgets and canary deployments keep massive systems fast and safe.

Luca also explains the hidden challenges most teams miss — governance, team topology, and socio-technical design.
He shows how to evolve from a monolith to micro-frontends step by step, using edge routing, feature flags, and domain-driven design to scale safely without rewrites.

The conversation goes beyond theory — into the mechanics of migration, platform teams, CI/CD pipelines, and why friction in your system is actually a signal, not a failure.

If you’re leading a frontend platform, planning a migration, or just trying to make sense of where micro-frontends actually fit, this episode is a masterclass in autonomy, architecture, and evolution at scale.

Chapters
00:00 The Origin of Micro-Frontends at DAZN05:41 Building a Distributed Frontend Without iFrames08:50 Designing the Application Shell and Stateless Architecture12:23 Zero Global State and Memory Management15:53 Guardrails for Bundle Size and Developer Discipline17:39 Governance and Designing for Scale20:18 When (and When Not) to Adopt Micro-Frontends22:46 Canary Releases and Edge Routing for Safe Migration25:49 Vertical vs Horizontal Splits in Micro-Frontends31:30 Lessons from Building the First Edition of the Book35:38 Frameworks, Federation, and Modern Tools39:22 Core Principles of Successful Frontend Architecture42:06 Building Platform Teams and Core Governance44:19 When Micro-Frontends Don’t Make Sense47:50 Micro-Frontends for Small Teams and Startups49:32 Monorepo vs Polyrepo – What Actually Matters53:10 Preventing Duplication and Encouraging Communication57:39 Why a Design System Is Non-Negotiable59:17 Common Anti-Patterns in Micro-Frontend Architecture

1:03:33 Book Recommendations and Final Thoughts

Follow & Subscribe:
📸 Instagram: https://www.instagram.com/senorsatscale/
📸 Instagram: https://www.instagram.com/neciudev
🎙 Podcast: https://neciudan.dev/senors-at-scale
📬 Newsletter: https://neciudan.dev/subscribe
💼 LinkedIn: https://www.linkedin.com/in/neciudan
💼 LinkedIn: https://www.linkedin.com/company/se%C3%B1ors-scale/

Additional Resources

📘 Building Micro-Frontends – Luca Mezzalira (O’Reilly) buildingmicrofrontends.com

🌐 buildingmfe.com

💬 Luca’s Blog: https://lucamezzalira.com

#microfrontends #aws #frontendarchitecture #javascript #webdevelopment #softwareengineering #softwarearchitecture #react #scaling #teamtopologies #serverless #señorsatscale

Don’t forget to like, comment, and subscribe for more engineering stories from the front lines.

How is your team approaching frontend scaling and independence? Share below 👇