A Software Engineer at Dataminr plays a pivotal role in the development of cutting-edge data analytics and real-time information systems that empower organizations to make informed decisions. This role is crucial for translating complex data sets into actionable insights, directly impacting products used by clients across various sectors, including finance, public safety, and corporate intelligence. As a Software Engineer, you will work on enhancing the capabilities of Dataminr’s products, contributing to the company’s mission of delivering timely and relevant data through innovative technology solutions. The position involves tackling complex challenges, such as designing scalable systems, implementing algorithms, and ensuring the robustness of applications. You will collaborate with cross-functional teams, including data scientists and product managers, to create features that not only meet user needs but also push the boundaries of what is possible with real-time data processing. Expect a dynamic work environment that encourages creativity and technical excellence, where your contributions can lead to significant advancements in how information is utilized globally.
Phone Screening
reportedInitial phone screening to assess candidate's background and fit for the role.
What to demonstrate
- Initial phone screening to assess candidate's background and fit for the role
- Depth in Data Structures & Algorithms
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 Interviews
reportedMultiple technical interviews that may include coding challenges and system design discussions.
What to demonstrate
- Multiple technical interviews that may include coding challenges and system design discussions
- Depth in Data Structures & Algorithms
How to prepare
- Answer aloud and timed: Describe how you would approach finding the k nearest positions from a given location on a map.
- Answer aloud and timed: Write a function to rotate a matrix in place.
PracHub editorial advice for the preparation topics above.
Practice coding regularly
Regularly solve coding problems on platforms like LeetCode or HackerRank to sharpen your skills and improve your speed and accuracy.
Engage in mock interviews
Conduct mock interviews with peers or use platforms that simulate technical interviews to gain confidence and receive feedback.
Study system design fundamentals
Familiarize yourself with system design principles, as many interviews will assess your ability to design scalable systems.
Prepare questions
Have thoughtful questions ready to ask your interviewers about the team and projects, demonstrating your interest in the role and company.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
How would you implement a function to find the median in a dynamic number stream?
How would you implement a function to find the median in a dynamic number stream?
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- 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?
Write a function to rotate a matrix in place.
Write a function to rotate a matrix in place.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- 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 would you tackle an NP-hard problem? Provide your thought process.
How would you tackle an NP-hard problem? Provide your thought process.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- 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?
Can you demonstrate how to implement a binary search algorithm?
Can you demonstrate how to implement a binary search algorithm?
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- 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?
Keep soft-deleted accounts from blocking re-registration
app_user holds user_id, tenant_id, email CITEXT, password_hash (NULL for SSO principals), email_verified_at, auth_version, status ('invited','active','suspended','deactivated'), created_at, updated_at, deleted_at. Two live accounts for one address inside a tenant must be impossible, but an address freed by a soft delete must be reusable, and the same tenant may delete and re-register it repeatedly. Write the uniqueness DDL for PostgreSQL 16, then the equivalent for MySQL 8 where partial indexes do not exist, and say what each permits once three deleted rows already hold that address.
Approach
- Start from what is actually unique: not (tenant_id, email), but (tenant_id, email) among live rows. PostgreSQL says that directly — CREATE UNIQUE INDEX app_user_live_email ON app_user (tenant_id, email) WHERE deleted_at IS NULL. A full constraint over the same two columns burns the address permanently the first time someone deletes an account.
- Keep case-insensitivity in the type or the index, never in the application: CITEXT as given, or UNIQUE (tenant_id, lower(email)) as an expression index where the extension is unavailable. A case-sensitive unique column is exactly how two accounts for one human appear.
- For MySQL 8 the predicate has to move inside the key: add a discriminator column that is a constant 0 while the row is live and is set to user_id on delete, with UNIQUE (tenant_id, email, deleted_marker). Live rows share the constant and still collide; deleted rows differ from each other and stop colliding.
- State the NULL variant and its dependency: leaving the marker NULL for deleted rows also works, because a unique index treats NULLs as distinct — true in MySQL, and true in PostgreSQL only under the default NULLS DISTINCT, which PostgreSQL 15 lets you reverse. Check the polarity against the three existing deleted rows: constant-on-live is what preserves the collision you want, and reversing it silently admits duplicate live accounts.
Follow-up
- A deleted account re-registers with the same address the next day. Do the old resource rows follow the new user_id, and how does the API keep the two principals apart?
- How do you honour an erasure request while resource_revision.actor_user_id still references this table?
Denormalise tenant onto revisions and backfill it live
resource_revision (revision_id, resource_id, version, actor_user_id, change_kind, patch, request_id, created_at) has 400M rows and no tenant column; tenant_id lives only on resource. Two reads need it: a tenant-scoped audit feed ordered by created_at DESC, and an offboarding purge. Both join back to resource today. Justify adding tenant_id to resource_revision against those two reads, name the anomaly the copy introduces and the constraint that prevents it, then give the ordered migration for a live table taking 1.2k writes/second — the lock each step takes, how the backfill is batched, and where each step stops being reversible. PostgreSQL 16.
Approach
- Justify from the access path rather than from taste. Without the column, the audit feed either scans resource_revision by created_at and discards other tenants' rows, or resolves the tenant's resource_ids first and probes with them — both proportional to the tenant's whole history rather than to one page. With (tenant_id, created_at DESC, revision_id DESC) it is a seek that stops at 50 rows, and the purge becomes a ranged delete instead of a join.
- Name the cost exactly: a second copy of a fact can disagree with the first. Make the disagreement unwritable rather than documented — add UNIQUE (resource_id, tenant_id) on resource so it can serve as a foreign-key target, then FOREIGN KEY (resource_id, tenant_id) REFERENCES resource (resource_id, tenant_id) on the revision table. A revision can then only ever carry its parent's tenant.
- Step one, expand: ALTER TABLE resource_revision ADD COLUMN tenant_id BIGINT NULL, with no default, so it is a catalogue change and no rewrite. It still needs ACCESS EXCLUSIVE for an instant, and that instant queues behind the longest open transaction on the table while every later query queues behind it — set lock_timeout to 2s and retry rather than wait.
- Step two, dual-write: deploy the writer that populates tenant_id on every new revision while reads still use the join. Reversible by redeploying the previous build, because nothing reads the column yet.
Follow-up
- The backfill is half finished and a rollback is required. What state is the table in, and what does the previous build do with a half-populated column?
- How do you verify the backfill actually finished, given rows are still being inserted while it runs?
Explain the concept of two heaps and how it can be used to solve problems efficiently.
Explain the concept of two heaps and how it can be used to solve problems efficiently.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe how you would approach finding the k nearest positions from a given location on a map.
Describe how you would approach finding the k nearest positions from a given location on a map.
Approach
- Say who the caller is and what they do when the call fails halfway.
- Define the identity of a request so a retry cannot double-apply it.
- Separate accepted, pending, failed and confirmed; they are different facts.
- Design the error taxonomy before the success shape; callers branch on it.
Follow-up
- What happens if the caller retries after a timeout?
- How does a client discover it is on an old version of this contract?
Design a system for real-time data processing. What components would you include?
Design a system for real-time data processing. What components would you include?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
How would you approach designing a microservices architecture?
How would you approach designing a microservices architecture?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Discuss the trade-offs between SQL and NoSQL databases in a scalable application.
Discuss the trade-offs between SQL and NoSQL databases in a scalable application.
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
How would you handle a scenario where your team is behind schedule on a critical project?
How would you handle a scenario where your team is behind schedule on a critical project?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Provide a strategy for optimizing an existing software application for better performance.
Provide a strategy for optimizing an existing software application for better performance.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
One log partition stops advancing while the others drain
Search results for a subset of tenants are hours stale; the rest are current. The projection consumer reports lag of zero on 15 of 16 partitions and 400,000 on one. Its error rate is flat and its CPU is idle. outbox_event has no pending rows older than a second, so the relay has published everything it holds. Identify the mechanism, give the ordered checks, and state what you do in the first ten minutes versus what you change permanently.
Approach
- Read the lag distribution first. A slow consumer lags everywhere; zero on fifteen partitions and 400,000 on one is not throughput. Idle CPU on the stuck partition means the consumer is not advancing its offset at all, which points at one message it cannot get past rather than at a rate problem.
- Exonerate the producer before touching the consumer. No pending outbox rows older than a second means the relay published, so the event exists in the log. This separates never sent from sent and never applied, which are different code paths and usually different owners.
- Read the message at the stuck offset and the handler's log lines for its event_id. A flat error rate with no progress has two explanations and you must distinguish them: the handler is throwing and the retry loop is swallowing it, or the handler is blocking on something and never returning. Idle CPU with no error lines favours the second.
- Mitigate before diagnosing further. Move the offending event to a dead-letter store and commit the offset past it. Adding consumers does nothing here, because a partition is consumed by exactly one member of the group, and the blast radius is every aggregate hashed to that partition, not only the aggregate that produced the bad event.
Follow-up
- The dead-lettered event carried aggregate_version 7 and the projection had applied 6. What must the replay do differently if 8 and 9 landed in the meantime?
- How do you show staleness to the user while the partition is behind, given the API already returns the projection's watermark?
Built from the rounds and topics Dataminr candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Dataminr loop
- Write out the reported sequence: Phone Screening, Technical 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 2 reported rounds, with the weakest marked.
02Work Data Structures & Algorithms
- Spend the session on Data Structures & Algorithms, which Dataminr candidates report being tested on.
- Write one worked example in Data Structures & Algorithms and time yourself on it.
Deliverable: One timed worked example in Data Structures & Algorithms.
03Work Coding Interview Problem Solving
- Spend the session on Coding Interview Problem Solving, which Dataminr candidates report being tested on.
- Write one worked example in Coding Interview Problem Solving and time yourself on it.
Deliverable: One timed worked example in Coding Interview Problem Solving.
04Work Heap Data Structures (Two Heaps)
- Spend the session on Heap Data Structures (Two Heaps), which Dataminr candidates report being tested on.
- Write one worked example in Heap Data Structures (Two Heaps) and time yourself on it.
Deliverable: One timed worked example in Heap Data Structures (Two Heaps).
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: How would you implement a function to find the median in a dynamic number stream?
- Answer aloud, timed: Explain the concept of two heaps and how it can be used to solve problems efficiently.
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Coding / Algorithms
- Answer aloud, timed: Write a function to rotate a matrix in place.
- Answer aloud, timed: How would you tackle an NP-hard problem? Provide your thought process.
Deliverable: Spoken answers to 2 reported Coding / Algorithms question(s), under time.
07Answer out loud: System Design / Architecture
- Answer aloud, timed: Design a system for real-time data processing. What components would you include?
- Answer aloud, timed: How would you approach designing a microservices architecture?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
Describe a situation where you had to navigate a conflict within your team. What was your approach?
Describe a situation where you had to navigate a conflict within your team. What was your approach?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- 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 working on multiple projects?
How do you prioritize your tasks when working on multiple projects?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- 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 example of how you took the initiative to solve a difficult technical challenge.
Share an example of how you took the initiative to solve a difficult technical challenge.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- 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?
Discuss a time when you had to learn a new technology quickly to meet a project requirement.
Discuss a time when you had to learn a new technology quickly to meet a project requirement.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- 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
Describe a situation where you had to navigate a conflict within your team. What was your approach?
- 02
How do you prioritize your tasks when working on multiple projects?
- 03
Share an example of how you took the initiative to solve a difficult technical challenge.
- 04
Discuss a time when you had to learn a new technology quickly to meet a project requirement.
What is the typical difficulty level of interviews at Dataminr?
The interviews are generally challenging, reflecting the high technical standards of the company. Candidates should be prepared for in-depth technical questions as well as behavioral assessments.
Dataminr Software Engineer candidate reports ↗How long does the interview process typically take?
The timeline can vary, but candidates often experience a multi-week process with several rounds of interviews. Expect to spend time on both technical evaluations and discussions about cultural fit.
Dataminr Software Engineer candidate reports ↗What differentiates successful candidates at Dataminr?
Successful candidates typically demonstrate strong technical skills, the ability to solve complex problems, and effective communication abilities. They align well with the company's values and culture.
Dataminr Software Engineer candidate reports ↗What is the company culture like at Dataminr?
Dataminr fosters a collaborative and innovation-driven culture. Teamwork, open communication, and a commitment to continuous learning are key aspects of the work environment.
Dataminr Software Engineer candidate reports ↗Are there remote work or hybrid options available?
While many roles may offer flexibility, specific arrangements will depend on team requirements and individual agreements. Candidates should clarify these details during the interview process.
Dataminr Software Engineer candidate reports ↗What topics does Dataminr test in interviews?
Dataminr interviews most often cover Stakeholder Management, Problem Solving, Python, Recruiter Coordination, and Analytical Problem Solving. The exact emphasis depends on the specific role you apply for.
Dataminr 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.
- 01Dataminr Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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