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DoorDash·Software Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
May 2026Remote

Summary

DoorDash system design round that threw a curveball: instead of the usual 'design this from scratch' setup, they gave me a live-outage scenario with constraints baked in, which meant none of my go-to technical fixes were on the table.

Questions Asked (1)

Q1

You're on call when a major payment system outage hits and your usual technical mitigations aren't available due to infrastructure limitations. Walk through how you'd handle triage, severity assessment, internal and external communication, customer impact mitigation, escalation, and postmortem.

Root Cause AnalysisStakeholder ManagementSystem Design
Author's notes

This one broke me a little.

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AI HintsAI Generated

Suggested Approach

Start by declaring the incident and assessing severity based on customer impact, then systematically work through triage, communication, mitigation, escalation, and postmortem. Emphasize clear communication, prioritization, and learning from the incident. Show that you can lead under pressure and coordinate across teams.

Pro tip: In high-pressure incidents, over-communicate with stakeholders and set expectations early—silence breeds panic. Document everything in real-time for the postmortem; it shows accountability and helps identify systemic issues.

1. Triage and Severity Assessment

Quickly determine the scope and impact: how many users, which payment methods, and revenue loss. Classify severity (e.g., SEV1) based on impact and escalate accordingly.

2. Communication and Coordination

Notify internal stakeholders (engineering, product, support) and external customers via status page and support channels. Set up a war room and assign roles.

3. Mitigation and Workarounds

Implement temporary fixes like disabling certain payment methods, rerouting traffic, or manual processing. Prioritize restoring service even if not perfect.

4. Escalation and Resource Mobilization

Engage senior engineers, vendors, and infrastructure teams. If needed, escalate to leadership for additional resources or decisions.

5. Postmortem and Prevention

Conduct a blameless postmortem to identify root cause, document timeline, and create action items to prevent recurrence.

Key Points to Mention

  • Customer impact quantification (e.g., number of failed transactions, revenue loss)
  • Clear and frequent communication with stakeholders (internal and external)
  • Prioritization of mitigation over root cause during active incident
  • Escalation paths and when to involve senior leadership
  • Blameless postmortem culture and actionable follow-ups
  • Documentation and timeline for learning and compliance

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.