Wix Engineering Newsletter, Issue 78: Cutting Costs, Boosting Resilience, and Smarter AI

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This month, we’re diving into cost-cutting wins, platform resilience, AI-powered coding, and productivity tips. Here’s what’s inside:

1. How Wix Cut 50% of Its Data Platform Costs (Part 1)

How did Wix cut data platform costs by 50%? At Wix, we run a massive, multi-cloud data platform that powers self-service for hundreds of data professionals. But that flexibility came at a cost - literally.

In Part 1 of our blog series, Valery Frolov shares:

• The visibility and attribution challenges we faced

• How we unified cost data from AWS, GCP, Snowflake & more

• Our approach to tagging, usage attribution, and cost modeling

If you're building or scaling a modern data platform, this post will help you lay the groundwork for real cost control. Read here

2. Engineering Resilience: Behind Wix’s Global Platform

Being responsible for a global platform at Wix means this: if we fail, millions of sites go dark. Downtime isn’t just costly - it’s unthinkable.

At Wix, we built two new systems - Production State & Traffic Light - that completely redefined how we manage traffic and infrastructure at scale.

The results?

• 80% faster recovery from incidents (MTTR)

• 60%+ of traffic moves fully automated

• A seamless user experience, even under pressure

Curious how we did it? Read this by post Ben Chen

3. Distributing Context Across Repositories

How do you make AI coding assistants truly useful? It all comes down to context!

In this talk, Ran Yitzhaki dives into how Cursor’s rules let developers carry instructions across coding sessions - and how teams can take it further with aicm, a tool for sharing and managing rules across repositories. Watch the full talk (Hebrew)

4. How Wix Slashed Spark Costs by 50%

At Wix, we pulled off a massive move: We migrated 5,000+ daily Spark applications from AWS EMR to EMR on EKS.

The results?

• 50% cost reduction

• Spin-up times cut from 10-15 minutes to just 2-3 minutes

• 99% transparent migration

EMR on EKS combined with Apache YuniKorn is truly a game-changer for big data workloads. Read the full story by Almog Gelber here.

5. More Insights We Liked

A roundup of great reads from Wix engineers and beyond:

• Words Matter: How Prompting Shapes Accuracy, Speed, and Cost - Yossi Goldstein on why prompt design makes or breaks LLM performance. Read here

• Harnessing Simulation - Ori Morhaim on using simulation to optimize staffing and ticket routing in customer care. Read here

• The AI Code Velocity Trap - Itai Schuftan on why AI-generated speed can create "day-one legacy code" and how to prevent accountability debt. Read here

• Must-Have Mac Apps in 2025 - Saar Shechter’s top productivity apps plus Reddit’s hidden gems. Read here

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