Santa Clara Family Health Plan Software Engineer Interview Guide

The 60-second brief

As a Software Engineer (often designated internally as an Application Developer I/II/III) at Santa Clara Family Health Plan, you play a vital role in supporting the health and well-being of over 300,000 residents in Santa Clara County. Santa Clara Family Health Plan is a local, public safety-net health plan dedicated to providing high-quality, affordable health insurance to low-income and vulnerable populations. In this role, your code and database solutions directly impact the delivery of critical healthcare services, claims processing, and member care management. The engineering team at Santa Clara Family Health Plan focuses heavily on data integration, system reliability, and secure processing of healthcare information.

This guide is scoped to a Software Engineer candidate at Santa Clara Family Health Plan.

Focus areas

• SQL
• Query Writing
• Interview Preparation Focus on SQL Mastery

The Santa Clara Family Health Plan interview process

Santa Clara Family Health Plan candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

HR Phone Screen

Initial call to assess basic qualifications, salary expectations, and cultural alignment.

What to demonstrate

• Initial call to assess basic qualifications, salary expectations, and cultural alignment
• Depth in SQL

How to prepare

• Be able to walk your CV end to end in two minutes, and say why this company specifically.
• Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.

Technical Assessment

Rigorous evaluation focused on SQL and database development, often requiring real-time problem-solving.

What to demonstrate

• Rigorous evaluation focused on SQL and database development, often requiring real-time problem-solving
• Depth in SQL

How to prepare

• Answer aloud and timed: Explain the difference between a LEFT JOIN, INNER JOIN, and OUTER JOIN, and provide a scenario in healthcare data where you would use each.
• Answer aloud and timed: Write a query using window functions to find the most recent medical claim for each member in a database.

Panel Interview

Comprehensive interview with engineering managers and directors, including behavioral and situational questions.

What to demonstrate

• Comprehensive interview with engineering managers and directors
• Including behavioral and situational questions

How to prepare

• Answer aloud and timed: How do you handle NULL values in aggregate functions like SUM or AVG to ensure reporting accuracy?
• Answer aloud and timed: Describe a time when you had to explain a complex technical issue or database limitation to a non-technical business stakeholder.

Where candidates lose points

Test Your Remote Setup

The technical interview often requires you to access a remote Windows machine via Remote Desktop Protocol (RDP) to write SQL queries.

Prepare for a Diverse Panel

You will likely meet with a large panel consisting of multiple managers, directors, and potentially executive leadership.

Treating a network call as though it were a local function call

A remote call can be slow, fail, or return after you stopped waiting, so name the timeout, the retry policy, and what the caller sees while the dependency is down. A call with no timeout turns one slow dependency into an exhausted thread or connection pool in every service upstream of it.

Questions & practice

Write a query to identify and merge duplicate member records based on specific demographic criteria.

Medium · SQL & Database Development

Approach

1. Restate the input: its shape, its size, and what is guaranteed about it.
2. Name the brute-force solution and its complexity before improving on it.
3. Choose the data structure from the access pattern, not from familiarity.
4. State the target complexity and say which constraint rules the naive version out.

Follow-up

• How does this change if the input no longer fits in memory?
• What is the worst case, and how likely is it on real data?

How do you maintain focus and deliver high-quality code when working under tight timelines or with ambiguous r

Medium · Adaptability & Work Ethic

How do you maintain focus and deliver high-quality code when working under tight timelines or with ambiguous requirements?

Approach

1. Restate the input: its shape, its size, and what is guaranteed about it.
2. Name the brute-force solution and its complexity before improving on it.
3. Choose the data structure from the access pattern, not from familiarity.
4. State the target complexity and say which constraint rules the naive version out.

Follow-up

• How does this change if the input no longer fits in memory?
• What is the worst case, and how likely is it on real data?

Canonicalise a request body into a stable idempotency fingerprint

Medium · parsing · canonicalisation · hashing

idempotency_key.request_fingerprint is a SHA-256 over the method, path and canonicalised body, and a retry whose fingerprint differs must be rejected with 422 rather than served the stored response. Write the canonicaliser. Bodies are JSON up to 256 KB nested at most 32 levels; clients vary key order, whitespace and unicode escaping, and some send 64-bit ids as JSON numbers. Produce a deterministic byte string such that semantically identical bodies match and any semantic difference does not. State your complexity and name two normalisations you refuse to perform.

Approach

1. Parse once into a tree, then re-serialise under fixed rules: object keys sorted, array order preserved, one escaping convention, no insignificant whitespace. Parsing is O(n) and sorting keys is O(k log k) per object, so O(n log n) overall with O(depth) stack, and the 32-level cap is enforced during parsing because hostile nesting is how a canonicaliser becomes a stack overflow.
2. Sort keys by their UTF-8 bytes and say why the obvious implementation is wrong in some runtimes: a default string comparison that orders by UTF-16 code units places surrogate pairs, meaning code points from U+10000 up, below U+E000 to U+FFFF, which is not UTF-8 byte order, so two services written in different languages disagree on the same document.
3. Do not re-encode numbers through a double. IEEE-754 binary64 represents integers exactly only up to 2^53, so normalising a 19-digit id through a float changes it, and 1 against 1.0 cannot be reconciled without deciding whether they are the same value. Preserve the literal token, and require ids as strings at the API boundary if you want them comparable.
4. Reject duplicate keys rather than picking one. JSON permits them and parsers disagree, most keeping the last, so any choice you make ties the fingerprint to a parser detail that the code handling the request does not necessarily share.

Follow-up

• A client sends the same logical request with an extra field your API ignores. Same key, different fingerprint, so you return 422. Is that the right answer?
• Where does the fingerprint get computed relative to request decompression and the body-size limit?

How would you optimize a slow-running JOIN operation across three large tables (e.g., claims, members, and p

Medium · SQL & Database Development

How would you optimize a slow-running JOIN operation across three large tables (e.g., claims, members, and providers)?

Approach

1. Name the grain you start from and join outward from it.
2. Check whether any join is one-to-many before aggregating, or the sums inflate.
3. Say which index the query would use, and what makes it unusable.
4. Handle the rows that do not match: that is usually the actual question.

Follow-up

• How does the query change if that join becomes one-to-many?
• What happens to this when the table is ten times larger?

Explain the difference between a LEFT JOIN, INNER JOIN, and OUTER JOIN, and provide a scenario in health

Medium · SQL & Database Development

Explain the difference between a LEFT JOIN, INNER JOIN, and OUTER JOIN, and provide a scenario in healthcare data where you would use each.

Approach

1. Name the grain you start from and join outward from it.
2. Check whether any join is one-to-many before aggregating, or the sums inflate.
3. Say which index the query would use, and what makes it unusable.
4. Handle the rows that do not match: that is usually the actual question.

Follow-up

• How does the query change if that join becomes one-to-many?
• What happens to this when the table is ten times larger?

Write a query using window functions to find the most recent medical claim for each member in a database.

Medium · SQL & Database Development

Approach

1. Name the grain you start from and join outward from it.
2. Check whether any join is one-to-many before aggregating, or the sums inflate.
3. Say which index the query would use, and what makes it unusable.
4. Handle the rows that do not match: that is usually the actual question.

Follow-up

• How does the query change if that join becomes one-to-many?
• What happens to this when the table is ten times larger?

Describe a situation where you had to work outside of standard business hours to resolve a critical system out

Medium · Adaptability & Work Ethic

Describe a situation where you had to work outside of standard business hours to resolve a critical system outage or meet a regulatory deadline.

Approach

1. Clarify what is being asked and what a complete answer contains.
2. State your assumptions explicitly before working the problem.
3. Say what you would check first and why it is the highest-information step.
4. Work from the requirement backwards to the design.

Follow-up

• What assumption would you test first?
• How would you know your answer was wrong?

What strategies do you use to quickly adapt to new technologies, platforms, or legacy systems that you have no

Medium · Adaptability & Work Ethic

What strategies do you use to quickly adapt to new technologies, platforms, or legacy systems that you have not worked with previously?

Approach

1. Clarify what is being asked and what a complete answer contains.
2. State your assumptions explicitly before working the problem.
3. Say what you would check first and why it is the highest-information step.
4. Work from the requirement backwards to the design.

Follow-up

• What assumption would you test first?
• How would you know your answer was wrong?

Read latency spikes on a sixty-second sawtooth

Medium · cache stampede · single-flight · ttl

The cached listing read path serves about 14k reads/second at an 85% hit rate. p99 sits at 35 ms for 57 seconds, jumps to 900 ms for 3, and repeats. During each spike the primary shows several hundred identical listing queries starting within the same millisecond, all carrying one large tenant's id. Cache entries use a 60-second TTL. Give the mechanism, the ordered checks, the fix, and the correctness hazard your fix must not introduce.

Approach

1. Match the period to a configured number before theorising about load. A spike every 60 seconds against a 60-second TTL is an entry expiring, and you confirm it by correlating spike timestamps with the entry's write time rather than with the traffic curve. If the period had matched a cron or a GC interval instead, this is a different investigation.
2. Establish the concurrency of the miss. Several hundred identical queries in one millisecond means the miss path has no coalescing: every request that arrives between expiry and repopulation recomputes. The herd size is that key's arrival rate times its recompute time, so at 1.2k reads/second for the hot key and a 250 ms recompute you expect about 300 concurrent misses, which matches what is observed.
3. Add single-flight on the miss path so one caller per key recomputes under a short-lived lock while the rest wait for its result. Prefer stale-while-revalidate where the read tolerates it: return the expired value immediately and refresh asynchronously, which removes the latency spike rather than serialising it into a queue of waiters.
4. De-synchronise the keys. Write TTLs with jitter, for example 60 seconds plus or minus 10%, so a deploy or a mass invalidation does not align every key on the same second and turn a per-key herd into a fleet-wide one.

Follow-up

• The same sawtooth appears on a key that is invalidated on write rather than expired. Is that the same bug?
• How does your answer change if the recompute takes 4 seconds instead of 250 ms?

Suggested practice checklist

Built from the rounds and topics Santa Clara Family Health Plan candidates report.

Day 1 — Map the Santa Clara Family Health Plan loop

• Write out the reported sequence: HR Phone Screen, Technical Assessment, Panel Interview.
• For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.

Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.

Day 2 — Work SQL

• Spend the session on SQL, which Santa Clara Family Health Plan candidates report being tested on.
• Write one worked example in SQL and time yourself on it.

Deliverable: One timed worked example in SQL.

Day 3 — Work Query Writing

• Spend the session on Query Writing, which Santa Clara Family Health Plan candidates report being tested on.
• Write one worked example in Query Writing and time yourself on it.

Deliverable: One timed worked example in Query Writing.

Day 4 — Work Interview Preparation Focus on SQL Mastery

• Spend the session on Interview Preparation Focus on SQL Mastery, which Santa Clara Family Health Plan candidates report being tested on.
• Write one worked example in Interview Preparation Focus on SQL Mastery and time yourself on it.

Deliverable: One timed worked example in Interview Preparation Focus on SQL Mastery.

Day 5 — Answer out loud: SQL & Database Development

• Answer aloud, timed: Write a query to identify and merge duplicate member records based on specific demographic criteria.
• Answer aloud, timed: How would you optimize a slow-running JOIN operation across three large tables (e.g., claims, members, and providers)?

Deliverable: Spoken answers to 2 reported SQL & Database Development question(s), under time.

Day 6 — Answer out loud: Behavioral & Collaboration

• Answer aloud, timed: Describe a time when you had to explain a complex technical issue or database limitation to a non-technical business stakeholder.
• Answer aloud, timed: How do you prioritize your deliverables when multiple managers or departments present you with competing high-priority requests?

Deliverable: Spoken answers to 2 reported Behavioral & Collaboration question(s), under time.

Day 7 — Answer out loud: Adaptability & Work Ethic

• Answer aloud, timed: Describe a situation where you had to work outside of standard business hours to resolve a critical system outage or meet a regulatory deadline.
• Answer aloud, timed: How do you maintain focus and deliver high-quality code when working under tight timelines or with ambiguous requirements?

Deliverable: Spoken answers to 2 reported Adaptability & Work Ethic question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

How do you handle NULL values in aggregate functions like SUM or AVG to ensure reporting accuracy?

Medium · SQL & Database Development

Approach

1. Pick a story where you made the decision, not one where you watched it.
2. State the situation in two sentences and spend the rest on the reasoning.
3. Give the blast radius: what could have broken, and what you measured.
4. Name the disagreement and how you resolved it with evidence.

Follow-up

• What would you do differently if you ran that again?
• How did you know your change caused the improvement?

Describe a time when you had to explain a complex technical issue or database limitation to a non-technical bu

Medium · Behavioral & Collaboration

Describe a time when you had to explain a complex technical issue or database limitation to a non-technical business stakeholder.

Approach

1. Pick a story where you made the decision, not one where you watched it.
2. State the situation in two sentences and spend the rest on the reasoning.
3. Give the blast radius: what could have broken, and what you measured.
4. Name the disagreement and how you resolved it with evidence.

Follow-up

• What would you do differently if you ran that again?
• How did you know your change caused the improvement?

How do you prioritize your deliverables when multiple managers or departments present you with competing high-

Medium · Behavioral & Collaboration

How do you prioritize your deliverables when multiple managers or departments present you with competing high-priority requests?

Approach

1. Pick a story where you made the decision, not one where you watched it.
2. State the situation in two sentences and spend the rest on the reasoning.
3. Give the blast radius: what could have broken, and what you measured.
4. Name the disagreement and how you resolved it with evidence.

Follow-up

• What would you do differently if you ran that again?
• How did you know your change caused the improvement?

Recall a situation where you identified a bug or data discrepancy in production. What steps did you take to re

Medium · Behavioral & Collaboration

Recall a situation where you identified a bug or data discrepancy in production. What steps did you take to resolve it and prevent future occurrences?

Approach

1. Pick a story where you made the decision, not one where you watched it.
2. State the situation in two sentences and spend the rest on the reasoning.
3. Give the blast radius: what could have broken, and what you measured.
4. Name the disagreement and how you resolved it with evidence.

Follow-up

• What would you do differently if you ran that again?
• How did you know your change caused the improvement?

How do you handle constructive criticism or feedback on your code during a peer review session?

Medium · Behavioral & Collaboration

Approach

1. Pick a story where you made the decision, not one where you watched it.
2. State the situation in two sentences and spend the rest on the reasoning.
3. Give the blast radius: what could have broken, and what you measured.
4. Name the disagreement and how you resolved it with evidence.

Follow-up

• What would you do differently if you ran that again?
• How did you know your change caused the improvement?