As a Software Engineer at TMC, you are not just a developer; you are an Employeneur. This role is central to the TMC business model, which bridges the gap between high-level technical consulting and long-term professional development. You will work on diverse, high-impact projects for a wide array of clients, requiring you to remain adaptable, technically proficient, and commercially aware. Your impact extends beyond writing code. You are expected to act as a bridge between technical requirements and client objectives, often working on-site or in close collaboration with client teams. The role is designed for engineers who thrive in dynamic environments and view their career as an entrepreneurial journey, where continuous learning, skill diversification, and personal initiative are the primary drivers of success. ##### Tip TMC values a proactive mindset. Because the company operates as a consulting firm, your ability to articulate how your technical skills solve specific business problems is as important as your coding ability.
Initial Screening Call
reportedThe process begins with a screening call to assess your qualifications and fit for the role.
What to demonstrate
- The process begins with a screening call to assess your qualifications and fit for the role
- Depth in Resume/project storytelling
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.
Interviews with Managers
reportedYou will have one or more interviews with Business Managers or technical leads to evaluate your skills.
What to demonstrate
- You will have one or more interviews with Business Managers or technical leads to evaluate your skills
- Depth in Resume/project storytelling
How to prepare
- Answer aloud and timed: What are your long-term professional ambitions?
- Answer aloud and timed: Are you comfortable working on-site at client locations?
Dossier or Portfolio Submission
reportedCandidates may be asked to complete a dossier or portfolio to showcase their work for potential client engagements.
What to demonstrate
- Candidates may be asked to complete a dossier or portfolio to showcase their work for potential client engagements
- Depth in Resume/project storytelling
How to prepare
- Answer aloud and timed: Can you walk me through a complex project from your CV and explain your specific contribution?
- Answer aloud and timed: How do you approach solving a technical problem you haven't encountered before?
PracHub editorial advice for the preparation topics above.
Prepare your "story
You will be asked about your CV repeatedly. Have a clear, concise narrative for every project listed.
Be transparent
If you have questions about the salary model or benefits, ask them early. TMC values transparency, and being clear about your expectations helps establish a professional relationship.
Focus on the "Why
Don't just explain what you did; explain why you chose one approach over another. This demonstrates the critical thinking expected of a consultant.
Follow up
If you don't hear back, follow up. Candidates report varying experiences with communication, so taking initiative is a sign of your professional maturity.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Merge partitioned event streams into one ordered feed with bounded lateness
The read-model service consumes 64 log partitions carrying about 4,000 events per second in total. Each partition is ordered within itself, but partitions drift by up to 30 seconds, and the activity feed must present a tenant's events in occurred_at order. Produce the merge. State its complexity, the buffer it requires in events and in bytes, what happens when one partition is idle, and what you do with an event that arrives after you have already emitted its position. Payloads average 1 KB.
Approach
- Merge with a min-heap over the 64 partition heads keyed on (occurred_at, event_id): O(log P) per event and O(n log P) overall. The tie-break on event_id is what makes the output deterministic when two partitions carry the same millisecond, which matters because the feed is paginated and a non-deterministic order reorders pages under the reader.
- Emitting the heap head is only correct once every partition has produced everything up to that timestamp, so the emit condition is a watermark: the minimum across partitions of the highest occurred_at seen, less the allowed lateness. Events are held until the watermark passes them, which is what turns individually ordered streams into a jointly ordered one.
- Size the buffer from the lateness rather than guessing: 4,000 events per second times 30 seconds is 120,000 buffered events, and at 1 KB each about 120 MB of heap. That number is the real price of the ordering guarantee and belongs in front of whoever asked for it.
- Handle the idle partition explicitly, because it fails the feed rather than corrupting it: a partition with no traffic never advances its own maximum, so the watermark freezes and output stops entirely. Either every partition emits a periodic idle marker carrying the broker's current time, or the watermark falls back to wall clock for a partition silent beyond a threshold.
Follow-up
- The lateness budget is raised to five minutes. What is the new buffer, and what besides memory changes?
- The consumer restarts. Where does it resume from, and what does the feed look like for the first 30 seconds?
Diff a projection against the primary without per-row point reads
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
- 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.
- 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.
- 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.
- 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?
Identify the heaviest tenants in a five-minute window under memory pressure
The edge service handles about 3,000 requests per second across roughly 50,000 tenants, peaking near 9,000. Expose the 50 heaviest tenants by request count over the trailing five minutes so limits can be tightened before one tenant's backfill starves the fleet. You may not retain five minutes of raw records. Give the exact solution and its memory, then the bounded-memory approximation with its error stated as a formula, and say which you would ship and at what tenant cardinality that choice changes.
Approach
- Do the exact version first, because it is affordable at this cardinality: a ring of 300 one-second counters per tenant, advanced lazily, is 1,200 bytes of counters per tenant and roughly 60 to 90 MB for 50,000 tenants with overhead. Carry a running total and subtract the bucket you overwrite so a window read is O(1) rather than 300 adds.
- Extract the top 50 with a size-k min-heap over the tenant sums: O(d log k) for d tenants, against O(d log d) to sort them all. Maintaining the heap continuously instead of on query requires a tenant-to-heap-index map, because incrementing a count already inside the heap means sifting from a known position, and without that map you rebuild the heap on every request.
- State the approximation precisely rather than gesturing at sketches. Misra-Gries with m counters retains every item whose true count exceeds N/(m+1), and each retained count underestimates the truth by at most N/(m+1). With m = 1,000 and N = 900,000 requests in the window the error is roughly 900 requests, which is fine for spotting a tenant sending 50,000 and useless for ranking two tenants 200 apart.
- Say what breaks when the window slides: Misra-Gries and Space-Saving are insert-only and cannot be decremented as records age out. The workable construction is one summary per sub-window, say ten seconds, with 30 summaries merged at query time, and the merged error is the sum of the per-summary errors, so the bound degrades linearly in the number of sub-windows.
Follow-up
- The heaviest tenant is heavy because of one export job rather than user traffic. Should the limiter treat those as the same tenant?
- Two tenants sit tied at the boundary of the top 50. Does your answer flap, and does the flapping matter?
Why do you want to join TMC and how does our business model align with your career goals?
Why do you want to join TMC and how does our business model align with your career goals?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- 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 the update path that detects a concurrent edit
resource carries version INT NOT NULL DEFAULT 1. resource_revision holds revision_id, resource_id, version, actor_user_id, change_kind, patch JSONB, request_id, created_at with UNIQUE (resource_id, version). outbox_event holds aggregate_type, aggregate_id, aggregate_version, event_type, payload, status. A PUT carries the version the client read. Write the exact statements for the single transaction that applies the edit, records the revision and enqueues 'resource.updated', and give the handler's branch on zero affected rows. Then say what PostgreSQL 16 does under READ COMMITTED when two of these updates hit one row at once.
Approach
- One transaction, three writes, no network call inside it: UPDATE resource SET title = $3, version = version + 1, updated_at = now() WHERE resource_id = $1 AND tenant_id = $4 AND version = $2; then INSERT the resource_revision row at version $2 + 1; then INSERT the outbox_event row at the same aggregate_version. The event goes to a table rather than a broker because no transaction spans both.
- Branch on the affected-row count before doing anything else. Zero has three causes — stale version, wrong tenant, row gone — so re-read once and map to 409 carrying the current version, or 404 for an id outside the caller's tenant, which also stops the endpoint confirming that another tenant's id exists.
- State the engine behaviour instead of assuming it. Under READ COMMITTED the second UPDATE blocks on the row lock, and when the first commits PostgreSQL re-evaluates the WHERE clause against the newly committed row, so the version predicate now fails and the statement reports zero rows. Under REPEATABLE READ the identical collision raises SQLSTATE 40001 instead, so the handler must fold both shapes into one conflict response.
- Keep UNIQUE (resource_id, version) even though the predicate already serialises writers. It is what makes a lost update unwritable if any other path ever reaches the revision table, and it converts a logic bug into 23505 rather than into a silently missing history row.
Follow-up
- A client sends the version it read ten minutes ago and the resource has moved three versions. What is in your 409 so it can resolve the conflict without a full re-fetch?
- Two editors, two disjoint fields, no overlap. Does your answer still refuse the second write, and should it?
What are your long-term professional ambitions?
What are your long-term professional ambitions?
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?
Are you comfortable working on-site at client locations?
Are you comfortable working on-site at client locations?
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?
Can you walk me through a complex project from your CV and explain your specific contribution?
Can you walk me through a complex project from your CV and explain your specific contribution?
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?
How do you approach solving a technical problem you haven't encountered before?
How do you approach solving a technical problem you haven't encountered before?
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?
How do you communicate technical concepts to non-technical stakeholders?
How do you communicate technical concepts to non-technical stakeholders?
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?
What are your expectations regarding professional growth and training?
What are your expectations regarding professional growth and training?
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 TMC candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the TMC loop
- Write out the reported sequence: Initial Screening Call, Interviews with Managers, Dossier or Portfolio Submission.
- 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.
02Work Resume/project storytelling
- Spend the session on Resume/project storytelling, which TMC candidates report being tested on.
- Write one worked example in Resume/project storytelling and time yourself on it.
Deliverable: One timed worked example in Resume/project storytelling.
03Work C++
- Spend the session on C++, which TMC candidates report being tested on.
- Write one worked example in C++ and time yourself on it.
Deliverable: One timed worked example in C++.
04Work Networking (computer networking)
- Spend the session on Networking (computer networking), which TMC candidates report being tested on.
- Write one worked example in Networking (computer networking) and time yourself on it.
Deliverable: One timed worked example in Networking (computer networking).
05Answer out loud: Background and Motivation
- Answer aloud, timed: Tell me about your academic background and your thesis work.
- Answer aloud, timed: Why do you want to join TMC and how does our business model align with your career goals?
Deliverable: Spoken answers to 2 reported Background and Motivation question(s), under time.
06Answer out loud: Technical Experience and Projects
- Answer aloud, timed: Can you walk me through a complex project from your CV and explain your specific contribution?
- Answer aloud, timed: How do you approach solving a technical problem you haven't encountered before?
Deliverable: Spoken answers to 2 reported Technical Experience and Projects question(s), under time.
07Answer out loud: Soft Skills and Professionalism
- Answer aloud, timed: How do you communicate technical concepts to non-technical stakeholders?
- Answer aloud, timed: Can you describe a time you had to adapt to a new project or environment quickly?
Deliverable: Spoken answers to 2 reported Soft Skills and Professionalism 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.
Tell me about your academic background and your thesis work.
Tell me about your academic background and your thesis work.
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?
Describe your experience with [specific technology mentioned in your CV].
Describe your experience with [specific technology mentioned in your CV].
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 handle technical disagreements within a team?
How do you handle technical disagreements within a team?
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?
Can you describe a time you had to adapt to a new project or environment quickly?
Can you describe a time you had to adapt to a new project or environment quickly?
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
Tell me about your academic background and your thesis work.
- 02
Describe your experience with [specific technology mentioned in your CV].
- 03
How do you handle technical disagreements within a team?
- 04
Can you describe a time you had to adapt to a new project or environment quickly?
How long does the process typically take?
The timeline varies significantly based on client needs, ranging from a few weeks to over a month. Always ask your recruiter for the current expected duration during your first call.
TMC Software Engineer candidate reports ↗Is there a technical test?
It depends. Some roles involve specific technical assessments or case studies, while others focus on deep-dive discussions about your past projects and architectural experience.
TMC Software Engineer candidate reports ↗What is the "dossier" or "portfolio" I keep hearing about?
This is a standard TMC requirement where you document your projects, skills, and experience in their specific format. This document is essential for presenting your profile to potential clients, so treat it with the same care as your CV.
TMC Software Engineer candidate reports ↗How important is my degree?
While your academic background is a point of discussion, TMC places a high value on your practical experience, projects, and your ability to apply knowledge to real-world problems.
TMC Software Engineer candidate reports ↗What topics does TMC test in interviews?
TMC interviews most often cover Stakeholder Communication, Python, SQL, Business case analysis, and Data Modeling. The exact emphasis depends on the specific role you apply for.
TMC 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.
- 01TMC 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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