John Hancock · Software Engineer
Updated · 2026-10-02

John Hancock Software Engineer
Interview Guide

THE 60-SECOND BRIEF

A Software Engineer at John Hancock plays a vital role in bridging modern technology with financial services. As a subsidiary of Manulife, John Hancock is a prominent leader in insurance, retirement, and wealth management. Engineers here do not just write code; they design, build, and maintain the digital platforms that manage millions of customers' financial portfolios, process insurance claims, and deliver seamless digital experiences. The applications you build directly impact the financial security and peace of mind of millions of users. In this role, you will work on modernizing legacy financial systems, migrating services to cloud-native architectures, and building intuitive customer-facing interfaces. The scale of the work is massive, requiring a strong focus on security, reliability, and performance.

This guide is scoped to a Software Engineer candidate at John Hancock.

John Hancock candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Behavioral Interviewing (STAR method)Situational InterviewingPair Programming

24 min read

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See the practice prompts

19Practice promptsAcross five skill areas

A Software Engineer at John Hancock plays a vital role in bridging modern technology with financial services. As a subsidiary of Manulife, John Hancock is a prominent leader in insurance, retirement, and wealth management. Engineers here do not just write code; they design, build, and maintain the digital platforms that manage millions of customers' financial portfolios, process insurance claims, and deliver seamless digital experiences. The applications you build directly impact the financial security and peace of mind of millions of users. In this role, you will work on modernizing legacy financial systems, migrating services to cloud-native architectures, and building intuitive customer-facing interfaces. The scale of the work is massive, requiring a strong focus on security, reliability, and performance. Whether you are optimizing a backend API, implementing a modern frontend framework, or designing a secure data pipeline, your contributions will drive the digital transformation of a household brand with over a century of history. Working at John Hancock offers a unique balance: the stability and resources of a massive financial institution combined with the forward-looking, agile mindset of a modern tech organization. You will collaborate with cross-functional teams of product managers, designers, and security experts to deliver robust software solutions that meet strict regulatory standards while maintaining an exceptional user experience.

01

Phone Screen

reported

Initial phone screen with HR to discuss your background, experience, and expectations.

What to demonstrate

  • Initial phone screen with HR to discuss your background, experience, and expectations
  • Depth in Behavioral Interviewing (STAR method)

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.
John Hancock Software Engineer candidate reports ↗
02

Technical Screen

reported

30-minute virtual call with a lead developer or engineering manager to review your resume and discuss technical background.

What to demonstrate

  • 30-minute virtual call with a lead developer or engineering manager to review your resume and discuss technical background
  • Depth in Behavioral Interviewing (STAR method)

How to prepare

  • Answer aloud and timed: How do you handle a situation where you disagree with a technical approach proposed by a senior team member?
  • Answer aloud and timed: Share an experience where a project you were working on did not go as planned. How did you adapt and what did you learn?
John Hancock Software Engineer candidate reports ↗
03

Technical Scenario Presentation

reported

Prepare and present a real-world technical problem to a panel, showcasing your approach and system design skills.

What to demonstrate

  • Prepare and present a real-world technical problem to a panel, showcasing your approach and system design skills
  • Depth in Behavioral Interviewing (STAR method)

How to prepare

  • Answer aloud and timed: How do you prioritize your tasks when managing multiple competing deadlines?
  • Answer aloud and timed: How would you architect a secure, scalable system to handle a large volume of concurrent insurance claims?
John Hancock Software Engineer candidate reports ↗
04

Behavioral Interviews

reported

Interviews with hiring managers, directors, or VPs to assess long-term alignment with the team and company culture.

What to demonstrate

  • Interviews with hiring managers, directors, or VPs to assess long-term alignment with the team and company culture
  • Depth in Behavioral Interviewing (STAR method)

How to prepare

  • Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
  • Re-read the description of the behavioral interviews above and write down what you would ask to confirm before it.
John Hancock Software Engineer candidate reports ↗

PracHub editorial advice for the preparation topics above.

01

Master the STAR Method

Ensure all your behavioral answers are structured, concise, and highlight your specific actions and the positive results achieved.

02

Emphasize Collaboration

John Hancock highly values team players. During pair programming or scenario presentations, communicate your thoughts clearly, ask questions, and show that you are receptive to feedback.

03

Issuing one query per row of a result set

Fetch related rows in a single batched query keyed by the ids you already hold, or join them into the original query. A per-row round trip multiplies network latency by the row count, and it looks perfectly fine against the ten rows in your development database.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

13 technical prompts0 include a worked solution

Find overlapping job attempts and peak concurrency from lease records

medium
sweep lineintervalsleases

A day of job_run history yields about 50,000,000 attempt records: (job_run_id, job_type, attempt, started_at, finished_at which is NULL when the worker died, lease_expires_at). Leases expire on a clock, so a job that outran its lease ran twice. Produce (a) every job_run_id whose attempts overlapped in wall-clock time and (b) the peak number of simultaneously running attempts per job_type with the minute it occurred. Target O(n log n). State how you treat a NULL finished_at and what clock skew does to your answer.

Approach
  1. Define the interval before sorting anything: an attempt occupies [started_at, COALESCE(finished_at, lease_expires_at)). finished_at is observed and lease_expires_at is only a promise, so every attempt without a finish contributes an estimate and the whole result is a lower bound on overlap rather than an exact count.
  2. For peak concurrency, sweep: emit 2n endpoints, sort by (timestamp, kind) with ends ordered before starts at equal timestamps, then walk the sequence maintaining a counter per job_type and record each type's maximum with its timestamp. O(n log n) dominated by the sort, O(n) space, or O(1) extra if the sort is external and the walk streams.
  3. For overlap detection, do not compare attempts pairwise. A single global sort by (job_run_id, started_at) gives both the grouping and the order; within a group, keep the maximum end seen so far and report an overlap exactly when the next start is less than that running maximum, which is one linear pass after the sort.
  4. Half-open intervals matter and are easy to get wrong: with closed intervals an attempt ending at the same millisecond another begins reads as concurrency two, and across 50,000,000 records that artefact swamps the real signal.
Follow-up
  • A handler is not idempotent and you have found 400 overlapping jobs. Which of them actually caused damage, and what would you query to find out?
  • Peak concurrency for one job_type is 4 against a configured cap of 4. Is the cap working, or is the data hiding attempts that never started?

Archive a resource graph without breaking live references or recursing

medium
graph traversaltopological ordertenant isolation

Resources reference other resources within a tenant; for the largest tenant the reference table holds up to 2,000,000 nodes and 8,000,000 edges. Archiving a resource must archive everything reachable from it that nothing outside the set still references, refuse when a live external referrer exists, and terminate when references form cycles, which they legitimately do. Produce the archive order and the refusal list, targeting O(V+E). Say what stops the traversal crossing a tenant boundary, and why recursion is the wrong control structure at this size.

Approach
  1. Load the subgraph with the tenant predicate on both endpoints of the edge, not only on the side you started from. Scoping the left table alone is the classic cross-tenant leak: one mis-entered edge then pulls another tenant's resources into the traversal and, worse, into the archive.
  2. Traverse iteratively with an explicit stack. A 2,000,000-node graph can hold a chain deep enough to exhaust a native stack in the low tens of thousands of frames, and that failure is a process crash rather than an error you can return.
  3. Treat cycles as data rather than corruption: compute strongly connected components with Tarjan in O(V+E) using its own explicit stack, then condense. The condensation is a DAG, so a topological order over it gives the archive order, and every member of a component archives in one transaction because no order within a cycle is valid.
  4. Decide refusals with reverse edges. A candidate is archivable only if every in-edge originates inside the candidate set, so build the transpose or count in-degrees restricted to the visited set, and emit each blocked resource with the id of the external referrer, which is the only part of the answer an operator can act on.
Follow-up
  • The graph is read in one query and the archive writes a minute later. What can change in between, and how do you make the write safe?
  • The candidate set is 400,000 resources. Is that one transaction, and if not, what does a half-finished archive look like to a reader?

Diff a projection against the primary without per-row point reads

hard
reconciliationrange hashingthrottling

The listing projection has drifted and some rows show a stale version. The primary holds 40,000,000 resource rows across 12,000 tenants while serving 1,200 writes and 14,000 reads per second. The obvious repair, reading each resource row and comparing its version against the projection, is correct and would eventually finish. Explain precisely why it is unacceptable here, then give a diff that finds the differing rows, state its complexity, and make it safe to run against a live primary. Replication lag is usually under 100 ms and is not bounded.

Approach
  1. Quantify the naive cost rather than calling it slow: 40,000,000 point reads at even 0.5 ms each is over five hours serialised, and the only lever is concurrency, which is exactly what you cannot spend. The primary's pool is sized for the write path, and 40,000,000 random reads evict the buffer cache that sustains the 85 percent cache hit rate, so the audit degrades the system it is auditing.
  2. Replace random access with one ordered pass per side. Both sides can be read in (tenant_id, resource_id) order, which is a sequential scan on each and a merge join in O(n) time and O(1) memory. For a dense diff that is the whole answer, and it reads the primary once instead of 40,000,000 times.
  3. For the expected sparse case, compare range hashes instead of rows: partition the key space, compute per range an order-independent aggregate over hash(resource_id, version), compare aggregates, and descend only into ranges that differ. With d differing rows and branching factor B, at most d ranges mismatch per level, so the drill-down examines O(d log_B(n/d)) ranges and reads full rows only in mismatching leaves.
  4. Aggregate with a sum modulo 2^64 or a multiset hash, never XOR. XOR is order-independent but self-cancelling, so two rows wrong in the same way, or a row duplicated on one side, leave the range aggregate matching and the range is declared clean.
Follow-up
  • The diff reports 900 stale rows. How do you decide between patching those rows and rebuilding the projection from resource_revision?
  • Same job, but the projection lives in a search index that cannot be scanned in key order. What changes?

Built from the rounds and topics John Hancock candidates report.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Map the John Hancock loop
  • Write out the reported sequence: Phone Screen, Technical Screen, Technical Scenario Presentation, Behavioral Interviews.
  • 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 4 reported rounds, with the weakest marked.

02Work Behavioral Interviewing (STAR method)
  • Spend the session on Behavioral Interviewing (STAR method), which John Hancock candidates report being tested on.
  • Write one worked example in Behavioral Interviewing (STAR method) and time yourself on it.

Deliverable: One timed worked example in Behavioral Interviewing (STAR method).

03Work Situational Interviewing
  • Spend the session on Situational Interviewing, which John Hancock candidates report being tested on.
  • Write one worked example in Situational Interviewing and time yourself on it.

Deliverable: One timed worked example in Situational Interviewing.

04Work Pair Programming
  • Spend the session on Pair Programming, which John Hancock candidates report being tested on.
  • Write one worked example in Pair Programming and time yourself on it.

Deliverable: One timed worked example in Pair Programming.

05Answer out loud: Behavioral & STAR Method Questions
  • Answer aloud, timed: Tell me about yourself and walk me through your past software engineering experience.
  • Answer aloud, timed: Describe a time when you had to make a technical decision under a tight deadline. What trade-offs did you make?

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

06Answer out loud: Technical Scenario & System Design
  • Answer aloud, timed: How would you architect a secure, scalable system to handle a large volume of concurrent insurance claims?
  • Answer aloud, timed: Imagine you are tasked with migrating a legacy on-premise application to the cloud. What are the key architectural decisions you must make?

Deliverable: Spoken answers to 2 reported Technical Scenario & System Design question(s), under time.

07Answer out loud: Technical & Domain-Specific Knowledge
  • Answer aloud, timed: What are the key differences between relational and non-relational databases, and when would you choose one over the other?
  • Answer aloud, timed: Explain your approach to testing. How do you balance unit testing, integration testing, and automated end-to-end testing?

Deliverable: Spoken answers to 2 reported Technical & Domain-Specific Knowledge question(s), under time.

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

Tell me about yourself and walk me through your past software engineering experience.

medium
Behavioral & STAR Method Questions

Tell me about yourself and walk me through your past software engineering experience.

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 make a technical decision under a tight deadline. What trade-offs did you make

medium
Behavioral & STAR Method Questions

Describe a time when you had to make a technical decision under a tight deadline. What trade-offs did you make?

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 a situation where you disagree with a technical approach proposed by a senior team member?

medium
Behavioral & STAR Method Questions

How do you handle a situation where you disagree with a technical approach proposed by a senior team member?

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?

Share an experience where a project you were working on did not go as planned. How did you adapt and what did

medium
Behavioral & STAR Method Questions

Share an experience where a project you were working on did not go as planned. How did you adapt and what did you learn?

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 tasks when managing multiple competing deadlines?

medium
Behavioral & STAR Method Questions

How do you prioritize your tasks when managing multiple competing deadlines?

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 your experience with modern frontend frameworks or cloud platforms, and how you leverage them to buil

medium
Technical & Domain-Specific Knowledge

Describe your experience with modern frontend frameworks or cloud platforms, and how you leverage them to build robust applications.

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?
  • 01

    Tell me about yourself and walk me through your past software engineering experience.

  • 02

    Describe a time when you had to make a technical decision under a tight deadline. What trade-offs did you make?

  • 03

    How do you handle a situation where you disagree with a technical approach proposed by a senior team member?

  • 04

    Share an experience where a project you were working on did not go as planned. How did you adapt and what did you learn?

PracHub preparation framework ↗
How technical is the initial phone interview?

The initial phone interview with HR is primarily conversational, focusing on your background, resume, and experience. However, the subsequent technical screen with a lead engineer will involve high-level technical discussions, resume deep dives, and situational engineering questions.

John Hancock Software Engineer candidate reports ↗
What is the unique "Technical Scenario" round?

In this round, you are given a real-world technical scenario related to a project you might work on at John Hancock. You have about 20 minutes to prepare answers to roughly six architectural and decision-making questions. You then present your approach for about 5 minutes and answer questions from the interviewers, allowing you to demonstrate your creativity and structured problem-solving.

John Hancock Software Engineer candidate reports ↗
What is the engineering culture like at John Hancock?

The engineering culture is highly collaborative, supportive, and focused on work-life balance. Teams are structured to encourage knowledge sharing, pair programming, and continuous learning. While the environment is stable and structured due to the financial domain, there is a strong push toward modernizing technologies and adopting cloud-native practices.

John Hancock Software Engineer candidate reports ↗
How long does the hiring process typically take?

The timeline can vary, but the process is generally smooth and well-paced. It typically takes anywhere from two to four weeks from the initial recruiter screen to the final offer, depending on team availability and scheduling.

John Hancock Software Engineer candidate reports ↗
What topics does John Hancock test in interviews?

John Hancock interviews most often cover SQL, Requirements Gathering, Business Analysis, Marketing Analytics, and Data Science (General). The exact emphasis depends on the specific role you apply for.

John Hancock Software Engineer candidate reports ↗
Sources & methodology 3 sources ↗

No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.