As a Software Engineer at Tendo, you will play a pivotal role in transforming the healthcare experience. Tendo is dedicated to building a seamless, integrated digital health platform that connects patients, clinicians, and caregivers. In this role, you are not just writing code; you are architecting and delivering applications that directly impact patient care, clinical workflows, and administrative efficiency. The solutions you build must handle complex data integrations, maintain strict security standards, and provide an intuitive, modern user experience. The engineering organization at Tendo tackles challenges at the intersection of scale, security, and usability. Because healthcare data is notoriously fragmented, your work will involve designing robust APIs, scalable microservices, and highly responsive frontends. Whether you are joining as a Senior Software Engineer, Principal Software Engineer, or Senior Principal Software Engineer, you will have a direct hand in shaping the technical roadmap, mentoring junior peers, and collaborating closely with product management to turn ambitious healthcare visions into reliable software. This position requires a blend of deep technical expertise and strong product empathy. You will be expected to make pragmatic architectural decisions that balance rapid feature delivery with long-term system stability.
Recruiter Screen
reportedBrief discussion to align on background, compensation, and role expectations.
What to demonstrate
- Brief discussion to align on background, compensation, and role expectations
- Depth in Prompt Interpretation & Requirements Compliance
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 Leadership
reportedSequential interviews with an Engineering Director and a VP focusing on past experiences and leadership philosophy.
What to demonstrate
- Sequential interviews with an Engineering Director and a VP focusing on past experiences and leadership philosophy
- Depth in Prompt Interpretation & Requirements Compliance
How to prepare
- Answer aloud and timed: How do you approach database schema design when dealing with highly unstructured or constantly changing medical record data?
- Answer aloud and timed: Explain how you would handle rate limiting and service degradation in a high-traffic healthcare application.
Live Product Demo
reportedInterview with an engineer to walk through a live product demo and assess product interest.
What to demonstrate
- Interview with an engineer to walk through a live product demo and assess product interest
- Depth in Prompt Interpretation & Requirements Compliance
How to prepare
- Answer aloud and timed: Tell me about a time when you had to make a significant architectural compromise to meet a tight product deadline.
- Answer aloud and timed: Describe a situation where you had to influence a product decision that you disagreed with from an engineering perspective.
Asynchronous Coding Project
reportedComplete a coding project that showcases your best work, which will be reviewed later.
What to demonstrate
- Complete a coding project that showcases your best work, which will be reviewed later
- Depth in Prompt Interpretation & Requirements Compliance
How to prepare
- Answer aloud and timed: How do you handle mentoring junior engineers while maintaining your own individual technical output?
- Answer aloud and timed: Tell me about a complex technical problem you solved recently and how you communicated the solution to non-technical stakeholders.
Panel Review
reportedPresent the coding project to a highly technical and collaborative engineering panel.
What to demonstrate
- Present the coding project to a highly technical and collaborative engineering panel
- Depth in Prompt Interpretation & Requirements Compliance
How to prepare
- Answer aloud and timed: Why did you choose this specific state management pattern/database/framework for your coding project?
- Answer aloud and timed: How would you refactor this project to handle ten times the current data volume?
PracHub editorial advice for the preparation topics above.
Over-deliver on the coding project
The written prompt may downplay the expected effort, but the panel will evaluate your submission with high standards. Treat the "toy" project as a production-grade assignment. Add robust error handling, write clean unit tests, and ensure the UI is polished.
Clarify the project scope early
If you receive a coding prompt that seems ambiguous or suggests limiting your time, do not hesitate to ask your recruiter or hiring manager for clarification on what the panel values most (e.g., architectural design, test coverage, or feature completeness).
Do not make assumptions about what the panel wants
If the prompt says "do not worry about X," but you know X is critical for a production application, implement it or be ready to explain exactly how you would implement it during the review.
Prepare detailed behavioral stories
The Director and VP rounds are highly conversational. Use the STAR method (Situation, Task, Action, Result) to describe past projects. Focus on how you managed technical debt, navigated team conflict, or delivered high-impact features under pressure.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Why did you choose this specific state management pattern/database/framework for your coding project?
Why did you choose this specific state management pattern/database/framework for your coding project?
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 refactor this project to handle ten times the current data volume?
How would you refactor this project to handle ten times the current data volume?
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?
What security vulnerabilities might exist in this implementation, and how would you mitigate them in a product
What security vulnerabilities might exist in this implementation, and how would you mitigate them in a production environment?
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 do you approach database schema design when dealing with highly unstructured or constantly changing medica
How do you approach database schema design when dealing with highly unstructured or constantly changing medical record data?
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?
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?
How do you design a secure, HIPAA-compliant API for sharing patient data between third-party systems?
How do you design a secure, HIPAA-compliant API for sharing patient data between third-party systems?
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?
Walk me through how you would architect a notification system that handles real-time alerts for patients and c
Walk me through how you would architect a notification system that handles real-time alerts for patients and clinicians.
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?
Explain how you would handle rate limiting and service degradation in a high-traffic healthcare application.
Explain how you would handle rate limiting and service degradation in a high-traffic healthcare application.
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?
If you had another week to work on this project, what architectural changes or features would you prioritize?
If you had another week to work on this project, what architectural changes or features would you prioritize?
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?
Listing latency scales with page size, not with filters
The tenant listing endpoint reads resource filtered by tenant_id and status, ordered by updated_at DESC, and returns each row plus the owner's display name from app_user and the actor of that resource's latest resource_revision. p99 is 55 ms at 10 rows per page and 1.4 s at 200. Database telemetry shows 401 statements per request, each under 1 ms, and nothing in the slow-query log. Diagnose the cause and give the fix, stating the statement count per request and the p99 you expect afterwards.
Approach
- Read the counters before forming a theory. 401 statements for 200 rows is one driver query plus two per row, and sub-millisecond execution with an empty slow-query log rules out a bad plan. The time is round trips, which is why it is invisible in every per-query metric and scales with rows returned rather than with filter selectivity.
- Name the two per-row statements from their normalised text: a single-row app_user lookup by user_id, and a resource_revision lookup by resource_id ordered by version DESC LIMIT 1. Confirm by dropping those two response fields and watching the statement count fall to one. That locates the calls in the serialisation layer, not the repository.
- Check that the arithmetic accounts for the whole gap. Measure one round trip to the replica in isolation; 400 trips at roughly 3 ms of network plus 0.2 ms of execution is about 1.3 s on top of a 55 ms baseline, which matches. If the multiplication had fallen short, the N+1 would only be part of the story and you would keep looking.
- Batch both lookups. Collect owner_user_ids and resource_ids from the driver query, then issue WHERE tenant_id = $1 AND user_id = ANY($2) for the users, and PostgreSQL's SELECT DISTINCT ON (resource_id) ... WHERE resource_id = ANY($2) ORDER BY resource_id, version DESC for the latest revision, which the UNIQUE (resource_id, version) index serves directly. On an engine without DISTINCT ON, use a lateral join or a row_number window. Three statements per request at any page size.
Follow-up
- The page size is capped at 200 today. What breaks first if it is raised to 2,000, and is it still this bug?
- How do you stop the next N+1 from reaching production, given that no individual query is slow and the endpoint's tests pass?
Built from the rounds and topics Tendo candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Tendo loop
- Write out the reported sequence: Recruiter Screen, Interviews with Leadership, Live Product Demo, Asynchronous Coding Project, Panel Review.
- 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 5 reported rounds, with the weakest marked.
02Work Prompt Interpretation & Requirements Compliance
- Spend the session on Prompt Interpretation & Requirements Compliance, which Tendo candidates report being tested on.
- Write one worked example in Prompt Interpretation & Requirements Compliance and time yourself on it.
Deliverable: One timed worked example in Prompt Interpretation & Requirements Compliance.
03Work Coding Project Exercises
- Spend the session on Coding Project Exercises, which Tendo candidates report being tested on.
- Write one worked example in Coding Project Exercises and time yourself on it.
Deliverable: One timed worked example in Coding Project Exercises.
04Work Handling Ambiguity in Technical Requirements
- Spend the session on Handling Ambiguity in Technical Requirements, which Tendo candidates report being tested on.
- Write one worked example in Handling Ambiguity in Technical Requirements and time yourself on it.
Deliverable: One timed worked example in Handling Ambiguity in Technical Requirements.
05Answer out loud: System Design & Architecture
- Answer aloud, timed: How do you design a secure, HIPAA-compliant API for sharing patient data between third-party systems?
- Answer aloud, timed: Walk me through how you would architect a notification system that handles real-time alerts for patients and clinicians.
Deliverable: Spoken answers to 2 reported System Design & Architecture question(s), under time.
06Answer out loud: Behavioral & Experience Discussion
- Answer aloud, timed: Tell me about a time when you had to make a significant architectural compromise to meet a tight product deadline.
- Answer aloud, timed: Describe a situation where you had to influence a product decision that you disagreed with from an engineering perspective.
Deliverable: Spoken answers to 2 reported Behavioral & Experience Discussion question(s), under time.
07Answer out loud: Coding & Project Review
- Answer aloud, timed: Why did you choose this specific state management pattern/database/framework for your coding project?
- Answer aloud, timed: How would you refactor this project to handle ten times the current data volume?
Deliverable: Spoken answers to 2 reported Coding & Project Review 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 a time when you had to make a significant architectural compromise to meet a tight product deadl
Tell me about a time when you had to make a significant architectural compromise to meet a tight product deadline.
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 a situation where you had to influence a product decision that you disagreed with from an engineering
Describe a situation where you had to influence a product decision that you disagreed with from an engineering perspective.
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 mentoring junior engineers while maintaining your own individual technical output?
How do you handle mentoring junior engineers while maintaining your own individual technical output?
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 complex technical problem you solved recently and how you communicated the solution to non-tec
Tell me about a complex technical problem you solved recently and how you communicated the solution to non-technical stakeholders.
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 a time when you had to make a significant architectural compromise to meet a tight product deadline.
- 02
Describe a situation where you had to influence a product decision that you disagreed with from an engineering perspective.
- 03
How do you handle mentoring junior engineers while maintaining your own individual technical output?
- 04
Tell me about a complex technical problem you solved recently and how you communicated the solution to non-technical stakeholders.
How difficult is the Tendo software engineering interview process?
The overall difficulty is rated as average, but the level of effort required for the coding project is high. While the behavioral and leadership rounds are conversational and discussion-based, the coding project requires significant attention to detail and a high standard of execution to pass the panel review.
Tendo Software Engineer candidate reports ↗What is the typical timeline from the recruiter screen to an offer?
The process generally takes 3 to 5 weeks. This timeline depends heavily on how quickly you complete the take-home coding project and the availability of the engineering panel for the review stage.
Tendo Software Engineer candidate reports ↗What are Tendo's expectations regarding remote or hybrid work?
Tendo has physical offices in Salt Lake City, UT, and San Francisco, CA. Depending on the specific team and seniority level, roles may be hybrid or fully remote within the United States, but candidates located near their primary hubs are highly valued.
Tendo Software Engineer candidate reports ↗How can I stand out during the engineering panel review?
Treat the coding project review as a collaborative design session. Be exceptionally transparent about the trade-offs you made, proactively point out areas where you would improve the code if given more time, and welcome constructive feedback from the panel.
Tendo Software Engineer candidate reports ↗What topics does Tendo test in interviews?
Tendo interviews most often cover Prompt Interpretation & Requirements Compliance, Data Engineering, SQL, Coding Project Exercises, and Principal Data Engineering (Leadership). The exact emphasis depends on the specific role you apply for.
Tendo 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.
- 01Tendo 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
Explore related engineering environments and compare the preparation focus.
CoreWeave Software Engineer Interview Guide
Failure-handling practice for CoreWeave software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
Aerospike Software Engineer Interview Questions & Guide 2026
Aerospike database-engine preparation through an original single-owner Python key-value store with bounded logical index accounting, disk-offset reads, conditional writes, tombstones, process-restart recovery and 3,240 checks. Existing 14 p
Western Alliance Bank Software Engineer Interview Guide
What Western Alliance Bank asks Software Engineer candidates, from reported rounds and questions.
Vanguard Software Engineer Interview Guide
What Vanguard asks Software Engineer candidates, from reported rounds and questions.