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ServiceNow data engineer interview: pipelines and SQL were the whole show

de_derek · 4 replies

Just wrapped up the ServiceNow data engineer interview loop last month and wanted to document this while it's fresh. Applied for a senior DE role on the Now Platform data infrastructure team out of San Diego (remote-eligible).

The process was five rounds total: recruiter screen, a 45-min SQL/coding screen, a pipeline design round, a behavioral round, and then a final team fit call.

SQL and coding screen

This was not LeetCode. It was actual, plausible SQL. Window functions, CTEs, a query about finding duplicate records in an event stream, one question about optimizing a slow query (they gave you an EXPLAIN plan to analyze). If you're a data engineer who hasn't touched SQL in a while because you've been living in Spark, spend a week here. They care.

One coding question in Python: write a function to flatten a nested JSON structure. Not hard, but they watched how you handled edge cases (None values, deeply nested keys).

Pipeline design round

This was the most interesting part. Prompt was something like: design a pipeline to ingest ServiceNow platform telemetry events (think IT operations data: incidents, changes, CMDB updates) and make them queryable by downstream analysts within 15 minutes of ingestion. They wanted me to talk through tooling choices, latency tradeoffs, failure modes, schema evolution.

I went with a Kafka-based ingestion layer feeding into Snowflake via dbt transformations, with a separate hot path to a Redis cache for the most recent 1 hour of data. They pushed back on the Redis layer and wanted me to defend it. That's fine, the defense is the point.

Behavioral round

Standard STAR stuff. Tell me about a time a pipeline failed in production. Tell me about a disagreement with a stakeholder about data quality. One question specifically about cross-functional work with SREs. Prep these, they matter at ServiceNow.

Comp at offer (declined, took something else) Senior DE, San Diego location: base was $185k, total cash around $195k with bonus. RSUs I wasn't shown until late in the process which was annoying. Market rate for a senior DE in 2026 in that geo felt right though, not exceptional.

Overall a well-run loop. The technical bar felt real, not performative.

4 replies

analyst_ana

the part about the EXPLAIN plan is really helpful. did they give you time to study it or was it shown cold on a shared screen?

de_derek

shown cold, maybe 2 minutes to read it before they asked what you'd do. not that complex though, a missing index was pretty obvious once you scanned the seq scans.

ux_uma

the schema evolution question is the one that gets people. did they want you to talk about backward vs forward compatibility specifically, or more just 'how do you not break things downstream'?

remote_swe_42

comp sounds light for senior DE in 2026. did they have room to negotiate or did they say band is fixed?