Walk through your background and proud project
Company: Discord
Role: Software Engineer
Category: Behavioral & Leadership
Difficulty: hard
Interview Round: HR Screen
## Interview prompts (behavioral)
1. **Walk me through your background and experience.**
- Focus on roles, scope, impact, and how your experience relates to a **persistence / database-infrastructure** team.
2. **Tell me about a specific project you’re proud of.**
- What was the problem?
- What was your role and what did you personally deliver?
- What was the measurable impact (latency, cost, availability, developer velocity, incidents reduced, etc.)?
- What trade-offs did you make?
3. **Do you have on-call experience?**
- Describe an incident you handled end-to-end.
- How did you communicate, mitigate, and prevent recurrence?
Quick Answer: This question evaluates communication, ownership, and technical leadership related to persistence and database-infrastructure, including on-call incident handling, impact measurement, and trade-off justification.
Solution
### What a strong answer looks like
#### 1) “Walk me through your background”
Use a tight **60–120 second** narrative:
- **Present:** your current role/team and the kind of systems you own (storage, databases, infra, reliability).
- **Past:** 1–2 relevant prior experiences (e.g., operating stateful systems, scaling data stores, building internal platforms).
- **Future:** why persistence/DB-infra specifically (operational rigor, correctness, performance, reliability).
A good structure:
- **Domain:** “I build/operate stateful systems…”
- **Scale:** QPS, data size, number of clusters, SLOs, incident rate.
- **Scope:** ownership boundaries (schema/engines, replication, backups, observability, tooling).
- **Impact:** quantifiable improvements.
Pitfalls:
- Too much chronology (“then I… then I…”) without impact.
- Vague claims (“improved performance a lot”) without numbers.
#### 2) “Project you’re proud of” (STAR + technical depth)
Use **STAR** but add engineering details:
- **S (Situation):** what broke / what was missing (e.g., slow queries, replication lag, noisy neighbors).
- **T (Task):** what success meant (SLO target, migration deadline, cost cap).
- **A (Actions):** 3–5 concrete technical actions you took.
- Examples for DB-infra: index redesign, query rewrites, partitioning/sharding strategy, replication topology changes, backup/restore automation, schema migration safety, observability.
- **R (Result):** metrics + what you learned.
Include trade-offs:
- Latency vs consistency (e.g., read replicas)
- Availability vs strong correctness
- Operational complexity vs performance gains
#### 3) “On-call experience”
Pick one incident and walk it end-to-end:
- **Detection:** alert, symptom, SLO burn, customer impact.
- **Triage:** what you checked first and why (dashboards, logs, replication lag, error budgets).
- **Mitigation:** safe stop-the-bleeding steps (rollback, failover, rate-limit, disable feature, expand capacity).
- **Communication:** who you informed, frequency, status updates.
- **Root cause:** how you confirmed it (not just guessed).
- **Prevention:** postmortem actions—tests, runbooks, alerts, automation.
What interviewers listen for:
- Calm prioritization (user impact first).
- “Safety mindset” for stateful systems (avoid data loss, verify before failover).
- Clear ownership and learning (not blame).
A concise on-call template:
- **Impact:** who/what broke
- **Timeline:** detect → mitigate → recover
- **Cause:** mechanism, not just component
- **Fixes:** immediate + long-term
- **Proof:** how you validated resolution (metrics, canary, audit checks)