25 articles by Xavier Redó
How we safely upgraded a legacy Rails app with limited tests
Upgrading a 150k-line Rails monolith with low test coverage is risky. We avoided a "big bang" by using progressive rollouts and bot traffic to ensure a stable, incident-free migration.
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How we made Plausible analytics work with ad blockers
To combat analytics data loss caused by ad-blockers, we implemented a custom Ruby on Rails proxy to route Plausible requests through our own backend. This privacy-friendly approach ensures we capture reliable traffic insights while fully respecting our visitors' data and privacy.
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Always use a .dockerignore in your projects
A missing .dockerignore slows down deployments and risks exposing sensitive data. Learn why this small but critical file is as essential as .gitignore.
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AI code agents and Typed Languages
AI code agents work best with typed languages. Better inference, safer refactors, and clearer APIs make typing feel like leverage rather than bureaucracy.
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React vulnerability (CVE-2025-66478): How we responded and what you should do
A critical React SSR vulnerability (CVE-2025-66478, CVSS 10.0) allows remote code execution. We have swiftly patched all active React/Next.js client projects. Users must apply the official fix immediately.
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How MarsBased website survived Cloudflare's global outage
After months of regional blocking in Spain, we rebuilt our stack to remove Cloudflare dependencies. Using Render and ImageKit.io, we replaced its performance layer without affecting users. So when Cloudflare went down globally on November 18, our site stayed online.
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Switching to Plausible: A privacy-friendly analytics tool for MarsBased
At MarsBased, we value privacy, simplicity, and open‑source tools. We replaced Google Analytics with Plausible, a lightweight, privacy‑first solution. This shift keeps us GDPR‑compliant while still providing the insights we need.
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How AI helped us bring back one-on-ones at MarsBased
With the help of AI, we finally solved one of our biggest management challenges at MarsBased, keeping one-on-ones consistent, meaningful, and well-documented across the team.
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Candidates priorities are changing
Candidates' priorities are shifting from methodology and how we work to how we economically manage our company and how we are financed.
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Scale IoT backends horizontally with MQTT Shared Subscriptions
In IoT architectures, choosing the right broker and strategy for consuming data is crucial. I recommend using message broker rules for scalability. If that doesn't fit your needs, consider messaging protocol strategies such as MQTT Shared Subscriptions.
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Comparison of MQTT Brokers for IoT
In our recent IoT project for Ecler, we designed their cloud platform and supporting systems for connected amplifiers and sound systems. During the development, we tested three message broker solutions: Mosquitto, NanoMQ, and EMQX. Here are the pros and cons we found for each one of them.
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Image optimization, delivery and CLS
Learn how to optimize web images: compress files, serve the right resolution, use WebP/AVIF, leverage CDNs, and eliminate cumulative layout shift (CLS).
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