Waystar sells software that helps healthcare providers get paid: checking insurance eligibility, submitting claims, tracking payments, and recovering denied claims. If you're interviewing for an application engineering role there, the interviewers will care about two things: whether you can build and debug software, and whether you understand why healthcare billing data is messy.
Waystar doesn't publish its interview process, so this guide doesn't claim to know the exact rounds. It covers what the company does (from its own website, checked October 2026) and the technical and domain topics you can reasonably prepare for. Ask your recruiter for the stages and the focus of each, and read the job description closely, since "application engineer" can mean different things between companies and teams.
What Waystar does
Waystar's website describes it as AI-powered software for healthcare revenue cycle management, meaning everything from verifying a patient's coverage to getting the final payment. Its platform areas include:
| Area | What it covers |
|---|---|
| Financial clearance | Eligibility verification, patient estimates, prior authorizations, price transparency |
| Clinical integrity and revenue capture | Documentation integrity, charge detection, anomaly identification |
| Claim and payer payment management | Claim monitoring, attachments, Medicare management |
| Payment management | Remittance processing, patient payment options, reimbursement tracking |
| Denial recovery | Appeal management and recoupment services |
| Analytics and reporting | Business intelligence and compliance reporting |
The site says it serves about a million providers, including health systems, physician practices, ambulatory surgery centers, billing services, skilled nursing, and home health. It also describes compliance with HIPAA, SOC 2, and HITRUST.
For an engineer, that suggests work on integrations with other healthcare systems, high-volume data processing, automation, analytics, and security.
What an application engineering role might involve
Titles vary, so confirm with the recruiter. Roles like this often involve:
- Building and maintaining features in a web application
- Working with APIs and integrations with customers' and payers' systems
- Investigating production issues from support or customers
- Reading logs, querying databases, and fixing data problems
- Working with product, support, and implementation teams
Technical topics to prepare
| Topic | What to be ready for |
|---|---|
| Core language (such as Java, C#, Python, or JavaScript) | Data structures, string and collection handling, object-oriented design |
| SQL | Joins, aggregates, window functions, finding duplicates, query performance |
| APIs and integration | REST, JSON, authentication, error handling, retries, idempotency |
| Debugging | Reading logs, reproducing a bug, narrowing the cause, writing a fix and a test |
| Data processing | Batch files, parsing formats, validating data, handling bad records |
| Testing | Unit and integration tests, test data |
| Cloud and deployment | Basics of cloud services, CI/CD, monitoring |
| Security and privacy | Protecting sensitive data, access controls, logging without leaking patient data |
For general coding practice, see our Big O cheat sheet and coding interview assistant guide. For design questions, see our system design interview guide.
Healthcare billing basics worth knowing
You aren't expected to be a billing expert, but a little domain knowledge helps you ask better questions. Terms you may meet:
| Term | Plain meaning |
|---|---|
| Revenue cycle management (RCM) | The process from scheduling a patient to collecting payment |
| Claim | A bill sent to an insurer for services given |
| Clearinghouse | A service that checks and routes claims between providers and payers |
| Payer | The insurance company or government program that pays |
| Eligibility check | Confirming a patient's coverage before or at service |
| Remittance advice | The payer's explanation of what it paid and why |
| Denial | A payer's refusal to pay a claim, often fixable and resubmitted |
| Prior authorization | Approval from the payer needed before some services |
| HIPAA | The US law on protecting patient health information |
Many healthcare transactions use standard electronic formats called X12, where claims, remittances, and eligibility each have their own transaction set. You don't need to know the codes by heart, but know that data arrives in standard but quirky formats, and that validation and error handling matter a great deal.
Sample questions and how to approach them
Walk me through debugging a claim that's failing validation.
"I'd start by reproducing it with the same input in a test environment, then read the error and the logs to find which field or rule failed. I'd check whether the data is wrong or the rule is, compare it with a similar claim that passed, fix the cause, add a test, and check whether other claims are affected."
How would you design a service that processes a large daily file of records?
"Read the file in a streaming way, validate each record, send bad records to a separate store with the reason, and process good ones in batches. Make processing idempotent so that a rerun doesn't duplicate work, record progress, and alert on failure. Log counts without logging sensitive data."
How do you handle sensitive data?
"Collect and keep only what's needed, encrypt it in transit and at rest, limit access by role, avoid sensitive data in logs and test data, and follow the company's compliance rules."
A customer reports data missing in a report. What do you do?
"Clarify what's missing and for which period, reproduce it, trace the data from source to report to find where it was lost, check recent changes, fix and backfill, and tell the customer what happened."
SQL: find customers with more than one open claim.
SELECT customer_id, COUNT(*) AS open_claims
FROM claims
WHERE status = 'open'
GROUP BY customer_id
HAVING COUNT(*) > 1;
Tell me about a time you fixed a hard production issue.
Prepare a story with the symptom, how you investigated, what you found, the fix, and what you changed to prevent a repeat. Use real numbers, such as hours of downtime or records affected.
Behavioral topics
Expect questions on working with non-technical colleagues, handling customer pressure, learning a new domain quickly, and owning mistakes. Prepare stories using the STAR structure, and see our behavioral guide.
Questions to ask
- What does a typical week look like for an application engineer on this team?
- How much of the work is new features versus investigating issues?
- How do engineers learn the healthcare billing domain?
- How are on-call and support handled?
- What does success look like in the first six months?
How to prepare
- Read the job description and the Waystar website, and list the technologies they name.
- Brush up on SQL and one language, using timed practice.
- Learn the billing terms above so the vocabulary is familiar.
- Prepare two debugging stories and one story about learning a new domain.
- Prepare questions about the team and the work.
Practice answers aloud, and read a mock interview transcript to see whether you explained your debugging steps in order. See our guide for software engineers' interview tools. Follow the employer's rules on AI tools in any live assessment.
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Run a mock technical interview, explain your debugging steps out loud, and review your transcript afterward. 30 free minutes, no subscription.
