Weak on trade-offs
The staff-plus signal is not knowing a technology — it's knowing when each choice becomes wrong. This path sharpens the trade-off muscle.
For: Senior engineers gunning for staff calibration
After this path
Defend every design choice with a specific trade-off — not "it's faster" but "we trade X for Y at our scale".
- 1Skill
Consistency trade-offs
Strong vs eventual vs causal, quorum, read-your-writes.
Why this, here: PACELC per data class, not per system. Most candidates get this wrong.
- 2Skill
Replication & durability
Leader/follower, sync vs async replication, write quorum, RPO/RTO.
Why this, here: Sync vs async replication; what you lose with each.
- 3Skill
Storage choice justification
Picking SQL vs KV vs doc vs blob vs timeseries based on access patterns.
Why this, here: Match access pattern to storage shape. "We use Postgres" is not a reason.
Checkpoint
Say out loud: the last design decision you made at work — what did you trade away to get it? If the answer is “nothing, it’s just better”, you haven’t framed the trade-off yet.
- 4Skill
Caching strategy
What to cache, TTLs, invalidation, write-through vs write-back, stampede.
Why this, here: Each cache pattern has a staleness window. Name the one you accept.
- 5Skill
Latency budgeting
p50/p99 targets, per-hop budgets, tail latency mitigation.
Why this, here: Every hop spends milliseconds. Sum them honestly before you commit to an SLO.