Scale Checkout Infrastructure for Holiday Peak

Project Background

ShopWave, a mid-market e-commerce platform, expects order volume to grow from 18,000 to 65,000 checkouts per minute during the 10-week holiday season. The CTO has asked you to lead a cross-functional effort to ensure the checkout, inventory, and payment systems can scale before November 1. The core team includes 11 people: 5 backend engineers, 2 SREs, 1 product manager, 1 QA lead, 1 data analyst, and you as program manager. The timeline is urgent because two enterprise retailers are scheduled to launch on the platform in the same quarter.

Key Stakeholders

The CTO wants confidence that the platform can handle peak traffic without a public outage. The VP of Sales wants the new retailers onboarded on time and is pushing for feature work to continue. The Head of Infrastructure wants to reduce incident risk and limit unplanned cloud spend. The Payments Director is focused on authorization success rates and low checkout latency.

Constraints

You have 12 weeks, a remaining budget of $420,000, and no approval for additional full-time hires. The team must maintain current production SLAs while delivering the scaling plan. A third-party payment gateway will not complete its API upgrade until Week 6, and the inventory service is owned by another team that can provide only 1 engineer at 25% allocation. Current system performance degrades above 28,000 checkouts per minute.

Complications

1. A major retailer has already been promised onboarding by Week 10, increasing traffic forecasts by 20%.
2. One senior SRE is scheduled for planned leave during Weeks 8-9, when load testing was originally planned.
3. Finance has warned that cloud costs cannot increase by more than 18% quarter over quarter.

Your Task

1. Build a 12-week execution plan to prepare the platform for peak traffic.
2. Define how you would prioritize scalability work versus feature commitments.
3. Identify the main risks, dependencies, and fallback options if the full target cannot be met.
4. Propose success metrics, launch readiness criteria, and a rollback approach.
5. Explain how you would align stakeholders with competing priorities throughout execution.