Code RoomStream-batch reconciliation
MediumPrep Room Coding #3550

Stream-batch reconciliation

System designDistributed systemsMid–Senior~35 min

A financial reporting warehouse aggregates transactions from a streaming pipeline (real-time) and a separate batch settlement file from the payment processor (authoritative, arrives next day). The two frequently disagree: the streaming total and the settlement total differ by small amounts due to dropped/late events, retries, currency rounding, and timezone cutoffs. Design an automated reconciliation system that detects, classifies, and surfaces these discrepancies so finance can trust the numbers and auditors can see a clean trail.

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.

Clarify4:00 left
Estimate4:00 planned
Design11:30 planned
Deep dive9:30 planned
Failure6:00 planned
0:00
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.