At Medra, a Software Engineer sits at the critical intersection of software development, robotics, and physical automation. You will be responsible for building the digital backbone that powers complex hardware systems, enabling seamless communication between cloud interfaces, local control systems, and robotic components. The software you build directly influences how physical machines perceive, navigate, and manipulate their environments, making your work highly tangible and impactful. This role requires a unique blend of systems-level thinking and full-stack execution. Whether you are designing communication protocols, building responsive user interfaces for operators, or optimizing low-latency data pipelines, your contributions will scale Medra's automation capabilities. You will work closely with cross-functional teams, including Mechanical Engineers and Systems Test Engineers, to deliver robust, production-grade systems that operate reliably in real-world environments. Success in this role means thriving in an environment of rapid prototyping, collaborative brainstorming, and rigorous testing. The challenges you will tackle are highly complex and rarely have pre-defined solutions. If you enjoy bridging the gap between digital logic and physical execution, this position offers an unparalleled opportunity to shape the future of automation.
Introductory Call
reportedInitial conversation with the Head of Robotics or hiring manager focusing on background, engineering interests, and alignment with Medra's mission.
What to demonstrate
- Initial conversation with the Head of Robotics or hiring manager focusing on background, engineering interests, and alignment with Medra's mission
- Depth in Encryption & Decryption
How to prepare
- Answer aloud and timed: Design and implement a custom encryption and decryption protocol to secure messages sent between a client and a robotic controller.
- Answer aloud and timed: How would you structure a lightweight data serialization format for transmitting high-frequency sensor data over a bandwidth-constrained network?
Technical Coding Interview
reportedPractical programming challenge with a lead engineer, focusing on clean implementation and logical flow.
What to demonstrate
- Practical programming challenge with a lead engineer
- Focusing on clean implementation and logical flow
How to prepare
- Answer aloud and timed: Write a program to parse and validate incoming command packets for a robotic system, ensuring malformed packets are safely rejected.
- Answer aloud and timed: Implement a thread-safe message queue that prioritizes critical system alerts over routine telemetry data.
Onsite Loop
reportedCombination of deeper technical discussions, system design, and behavioral interviews.
What to demonstrate
- Combination of deeper technical discussions, system design, and behavioral interviews
- Depth in Encryption & Decryption
How to prepare
- Answer aloud and timed: How would you design the software architecture for a full-stack system that allows remote operators to monitor and control a robotic arm in real-time?
- Answer aloud and timed: Describe your approach to managing state synchronization between a local robot controller and a cloud-based dashboard.
PracHub editorial advice for the preparation topics above.
Over-communicate your thought process
Do not solve problems in silence. Talk through your assumptions, explain why you are choosing a specific data structure, and outline your approach before you begin writing code.
Focus on edge cases early
When designing protocols or writing code, explicitly state the edge cases you are considering (e.g., network drops, null inputs, buffer overflows) and explain how your solution handles them.
During protocol design questions, prioritize clean code and explain your architectural choices before writing any code
Let the interviewer know why you chose a specific data structure or algorithm.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
How would you structure a lightweight data serialization format for transmitting high-frequency sensor data ov
How would you structure a lightweight data serialization format for transmitting high-frequency sensor data over a bandwidth-constrained network?
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 program to parse and validate incoming command packets for a robotic system, ensuring malformed packet
Write a program to parse and validate incoming command packets for a robotic system, ensuring malformed packets are safely rejected.
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?
Implement a thread-safe message queue that prioritizes critical system alerts over routine telemetry data.
Implement a thread-safe message queue that prioritizes critical system alerts over routine telemetry data.
Approach
- Say what the runtime actually does before reasoning about the code.
- Name what is shared across threads and what owns each piece of state.
- Identify the window where an invariant is briefly untrue.
- Distinguish a value from a reference to it, and say which one you handed out.
Follow-up
- What happens if two callers reach this at the same time?
- Where could this allocate more than you expect?
Stop tag and share joins from fanning out a page
resource_tag is (resource_id, tag_id) with PK (resource_id, tag_id); resource_share is (resource_id, shared_with_user_id, permission). The tagged-and-shared listing inner-joins resource to both, filters tenant_id, tag_id = ANY($2) and shared_with_user_id = $3, orders by updated_at DESC and takes 50. Pages come back with fewer than 50 distinct resources and the total in the header is far too high. Explain the row multiplication, rewrite both the page query and the count query so each is correct, and name the index each one needs. PostgreSQL 16.
Approach
- Do the arithmetic against the predicates that are actually there. An inner join emits one row per matching child row, and both joins are filtered: tag_id = ANY($2) admits only the requested tags, shared_with_user_id = $3 admits one user's share rows. So a resource holding three of the requested tags and shared with $3 once yields three rows, not one — the multiplier is its count of matching tags times its share rows for that single user, and that second factor is 1 unless the table admits duplicate (resource_id, shared_with_user_id) pairs. LIMIT 50 then limits rows rather than resources, and COUNT(*) counts pairs — the header is the product, not the population.
- Reject DISTINCT as the fix. It deduplicates after the product has been built, so the planner must materialise and sort the fanned-out set before the LIMIT can apply, and it leaves any SUM or AVG in the same select list wrong.
- Rewrite both filters as semi-joins, keeping resource as the only row source: AND EXISTS (SELECT 1 FROM resource_tag rt WHERE rt.resource_id = r.resource_id AND rt.tag_id = ANY($2)) and the same shape against resource_share. A semi-join stops at the first match per resource and preserves the driving index order, so ORDER BY updated_at DESC, resource_id DESC LIMIT 50 still stops after 50 rows.
- Count with the same predicates and no join at all: SELECT count(*) FROM resource r WHERE r.tenant_id = $1 AND r.status = 'active' AND EXISTS (...) AND EXISTS (...). Nothing multiplies a resource, so the number is the population.
Follow-up
- The filter changes from 'any of these tags' to 'all of these tags'. Rewrite it and state what it costs relative to the ANY form.
- A resource can be shared with the same user twice under different permissions. Does your count change, and should it?
Replace offset paging on the resource feed with keyset
resource holds resource_id, tenant_id, owner_user_id, title, body_ref, version, status ('draft','active','archived','deleted'), created_at, updated_at, deleted_at, with an index on (tenant_id, status, updated_at DESC, resource_id DESC). The listing endpoint returns active resources for one tenant, newest update first, 50 per page, today with LIMIT 50 OFFSET n. Tenants reach page 400 and rows are created while they read. Write the keyset query, define what the cursor carries and how it is encoded, and say which part of the index each predicate uses. Assume PostgreSQL 16.
Approach
- Name the two failures separately. OFFSET 20000 makes the server produce and discard 20,000 rows, so page cost grows with depth rather than with page size. Independently, any write that changes how many rows sort above the offset moves the window between two fetches, and the direction decides which anomaly you get: an insert lands at the head of updated_at DESC and pushes already-returned rows down past the boundary, so they are returned a second time; a delete above the offset, or a row whose updated_at is bumped above the cursor, pulls rows up and one is never returned at all. Nothing in the response reveals either.
- Write the seek: WHERE tenant_id = $1 AND status = 'active' AND (updated_at, resource_id) < ($2, $3) ORDER BY updated_at DESC, resource_id DESC LIMIT 50. The row-value comparison is one index range rather than a disjunction, and both columns are NOT NULL, which is what makes that comparison well defined.
- Map each predicate onto the index: tenant_id and status are equality on the leading columns, (updated_at, resource_id) is the range, and the ORDER BY matches the index order so no Sort node appears and the scan stops after 50 rows. The DESC in the definition only matters for mixed directions — a plain ascending btree on the same columns is read backwards for this query.
- Put both sort columns in the cursor and nothing the client can tamper with into another tenant: base64 of (updated_at, resource_id), validated server-side, with tenant_id taken from the principal.
Follow-up
- The client asks for 'jump to page 400'. What do you offer instead, and what does the honest version cost?
- Sort order becomes user-selectable across four columns. How many indexes is that, and which would you refuse to add?
Design and implement a custom encryption and decryption protocol to secure messages sent between a client and
Design and implement a custom encryption and decryption protocol to secure messages sent between a client and a robotic controller.
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 design the software architecture for a full-stack system that allows remote operators to monitor
How would you design the software architecture for a full-stack system that allows remote operators to monitor and control a robotic arm in real-time?
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?
Describe your approach to managing state synchronization between a local robot controller and a cloud-based da
Describe your approach to managing state synchronization between a local robot controller and a cloud-based dashboard.
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 sudden loss of network connectivity in a distributed robotics system to ensure the phys
How would you handle a sudden loss of network connectivity in a distributed robotics system to ensure the physical hardware remains in a safe state?
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?
Design an API that exposes hardware telemetric data to third-party developers while maintaining strict access
Design an API that exposes hardware telemetric data to third-party developers while maintaining strict access controls.
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?
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 Medra candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Medra loop
- Write out the reported sequence: Introductory Call, Technical Coding Interview, Onsite Loop.
- 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 Encryption & Decryption
- Spend the session on Encryption & Decryption, which Medra candidates report being tested on.
- Write one worked example in Encryption & Decryption and time yourself on it.
Deliverable: One timed worked example in Encryption & Decryption.
03Work Cryptographic Protocol Design
- Spend the session on Cryptographic Protocol Design, which Medra candidates report being tested on.
- Write one worked example in Cryptographic Protocol Design and time yourself on it.
Deliverable: One timed worked example in Cryptographic Protocol Design.
04Work Protocol Correctness & Security Reasoning
- Spend the session on Protocol Correctness & Security Reasoning, which Medra candidates report being tested on.
- Write one worked example in Protocol Correctness & Security Reasoning and time yourself on it.
Deliverable: One timed worked example in Protocol Correctness & Security Reasoning.
05Answer out loud: Protocol Design & Coding
- Answer aloud, timed: Design and implement a custom encryption and decryption protocol to secure messages sent between a client and a robotic controller.
- Answer aloud, timed: How would you structure a lightweight data serialization format for transmitting high-frequency sensor data over a bandwidth-constrained network?
Deliverable: Spoken answers to 2 reported Protocol Design & Coding question(s), under time.
06Answer out loud: Systems & Architecture
- Answer aloud, timed: How would you design the software architecture for a full-stack system that allows remote operators to monitor and control a robotic arm in real-time?
- Answer aloud, timed: Describe your approach to managing state synchronization between a local robot controller and a cloud-based dashboard.
Deliverable: Spoken answers to 2 reported Systems & Architecture question(s), under time.
07Answer out loud: Behavioral & Collaboration
- Answer aloud, timed: Describe a time when you had to work closely with hardware or mechanical engineers to diagnose and resolve a complex system failure.
- Answer aloud, timed: How do you approach technical disagreements within a team when choosing between two competing architectural designs?
Deliverable: Spoken answers to 2 reported Behavioral & Collaboration 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 time when you had to work closely with hardware or mechanical engineers to diagnose and resolve a c
Describe a time when you had to work closely with hardware or mechanical engineers to diagnose and resolve a complex system failure.
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 approach technical disagreements within a team when choosing between two competing architectural de
How do you approach technical disagreements within a team when choosing between two competing architectural designs?
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?
Tell me about a project where you had to quickly learn a new technology or domain to deliver a critical featur
Tell me about a project where you had to quickly learn a new technology or domain to deliver a critical feature.
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 balance the need for rapid prototyping and speed with long-term code quality and system reliability
How do you balance the need for rapid prototyping and speed with long-term code quality and system reliability?
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 time when you had to work closely with hardware or mechanical engineers to diagnose and resolve a complex system failure.
- 02
How do you approach technical disagreements within a team when choosing between two competing architectural designs?
- 03
Tell me about a project where you had to quickly learn a new technology or domain to deliver a critical feature.
- 04
How do you balance the need for rapid prototyping and speed with long-term code quality and system reliability?
What is the typical programming language expectation during the interview?
Medra is highly language-agnostic during the coding phases. You are encouraged to use the programming language you are most comfortable with, whether that is Python, C++, Go, or JavaScript, as long as you can write clean, structured, and idiomatic code.
Medra Software Engineer candidate reports ↗How much hardware or robotics experience do I need?
While prior experience with robotics, ROS, or hardware integration is a strong plus, it is not a strict requirement for all software roles. Strong software engineering fundamentals, systems-level intuition, and a genuine eagerness to learn about hardware are highly valued.
Medra Software Engineer candidate reports ↗What is the hybrid or remote work policy for this role?
Because this role involves direct integration with physical robotic systems, regular onsite presence at the San Francisco, CA office is typically required. This allows close collaboration with the hardware and systems testing teams.
Medra Software Engineer candidate reports ↗How long does the entire interview process take?
The process typically takes between two to four weeks from the initial introductory call to the final decision, depending on scheduling availability and the speed of candidate progression.
Medra Software Engineer candidate reports ↗What topics does Medra test in interviews?
Medra interviews most often cover Programming Language Agnosticism, Encryption & Decryption, Encryption and Decryption Protocols, Cryptographic Protocol Design, and Cryptography Concepts. The exact emphasis depends on the specific role you apply for.
Medra 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.
- 01Medra 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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