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interview questions

Hi everyone,

What kind of interview questions are generally asked for OutSystems developers with 2+ years of experience?

It would be helpful if you could share some commonly asked technical and scenario-based questions.


Thanks

2026-02-26 06-29-24
Rahul
 
MVP
Solution

Hi @Rajkamal Singh Jhala ,

If I were interviewing a 2+ year OutSystems developer, I'd focus most on:

SQL → Exception Handling → REST API → Aggregates → Lists → Timers → Performance → Security → Data Modeling → Real-world scenarios

The interviewer is much more likely to ask “How would you implement this?” / “What happens if this fails?” / “How would you optimize this?” than simply “What is an Aggregate?”.


Here are the key areas I would recommend preparing:

1. SQL & Database

  • Complex queries & Joins (1:1, 1, M)
  • Aggregates vs Advanced SQL
  • Query optimization & Indexing
  • Pagination & Large datasets
  • Transactions & Bulk operations
  • Stored Procedures
  • Duplicate & NULL handling

2. Data Modeling

  • Entity design for real-world scenarios
  • 1:1, 1, M relationships
  • Junction entities
  • Reference vs Identifier
  • Delete rules & Indexing
  • Normalization / Denormalization
  • Audit & Historical data

3. Exception Handling

  • Exception Handler & Custom Exceptions
  • Exception propagation
  • Rollback / Transactions
  • Handling exceptions in loops
  • API & Database exceptions
  • Logging & meaningful error handling
  • Avoiding swallowed exceptions

4. REST API / Integration

  • Consume / Expose REST APIs
  • HTTP status codes
  • Authentication & OAuth
  • Request/Response & JSON mapping
  • Timeout & Retry mechanisms
  • Idempotency
  • Pagination & File handling
  • API failure handling

5. Client vs Server Logic

  • Client Action vs Server Action
  • Minimizing server calls
  • Client/Server data handling
  • Validation
  • Screen state & Refresh logic

6. Lists & Aggregates

  • List manipulation & ListAppend
  • Filtering / Sorting / Mapping
  • Duplicate handling
  • Multiple joins & Dynamic filters
  • Group By / Aggregations
  • Large List processing
  • Aggregate optimization

7. Timers & Background Processing

  • Batch processing
  • Large-volume processing
  • Retry & failure handling
  • Idempotent Timers
  • Concurrent execution
  • Avoiding duplicate processing
  • Recovery mechanisms

8. Performance

  • Slow screen / Aggregate / API troubleshooting
  • Database optimization
  • Large data handling
  • Client-server communication
  • Monitoring & production troubleshooting

9. Security

  • Roles & Authorization
  • Server-side validation
  • API security
  • SQL Injection / XSS
  • Authentication vs Authorization
  • Sensitive data handling

10. Reactive UI

  • Form & Dynamic validation
  • Parent/Child communication
  • Screen lifecycle
  • Multiple data sources
  • Refresh & state management

11. Architecture

  • Layered architecture
  • Core / Service / UI responsibilities
  • Reusability
  • Dependency management
  • Circular dependencies
  • Coupling / Cohesion
  • Refactoring

12. Real-World ScenariosFocus especially on implementation scenarios such as:

  • Processing 20K+ records efficiently
  • Handling API failures and retries
  • Preventing duplicate Timer processing
  • Handling concurrent updates
  • Optimizing a screen loading thousands of records
  • Implementing audit/history
  • Designing scalable integrations
  • Troubleshooting production performance issues
UserImage.jpg
Rajkamal Singh Jhala

Thank u 

2026-01-28 16-57-48
Mihai Melencu
Champion

Hi @Rajkamal Singh Jhala ,

From my experience, interviews usually focus on practical experience rather than definitions.

Scenario-based questions might include processing large datasets, securing data, handling integrations or designing reusable functionalities. 

Be prepared to discuss a real project, the challenges you faced, how you solved them, and the reasoning behind your decisions.

2026-02-26 06-29-24
Rahul
 
MVP
Solution

Hi @Rajkamal Singh Jhala ,

If I were interviewing a 2+ year OutSystems developer, I'd focus most on:

SQL → Exception Handling → REST API → Aggregates → Lists → Timers → Performance → Security → Data Modeling → Real-world scenarios

The interviewer is much more likely to ask “How would you implement this?” / “What happens if this fails?” / “How would you optimize this?” than simply “What is an Aggregate?”.


Here are the key areas I would recommend preparing:

1. SQL & Database

  • Complex queries & Joins (1:1, 1, M)
  • Aggregates vs Advanced SQL
  • Query optimization & Indexing
  • Pagination & Large datasets
  • Transactions & Bulk operations
  • Stored Procedures
  • Duplicate & NULL handling

2. Data Modeling

  • Entity design for real-world scenarios
  • 1:1, 1, M relationships
  • Junction entities
  • Reference vs Identifier
  • Delete rules & Indexing
  • Normalization / Denormalization
  • Audit & Historical data

3. Exception Handling

  • Exception Handler & Custom Exceptions
  • Exception propagation
  • Rollback / Transactions
  • Handling exceptions in loops
  • API & Database exceptions
  • Logging & meaningful error handling
  • Avoiding swallowed exceptions

4. REST API / Integration

  • Consume / Expose REST APIs
  • HTTP status codes
  • Authentication & OAuth
  • Request/Response & JSON mapping
  • Timeout & Retry mechanisms
  • Idempotency
  • Pagination & File handling
  • API failure handling

5. Client vs Server Logic

  • Client Action vs Server Action
  • Minimizing server calls
  • Client/Server data handling
  • Validation
  • Screen state & Refresh logic

6. Lists & Aggregates

  • List manipulation & ListAppend
  • Filtering / Sorting / Mapping
  • Duplicate handling
  • Multiple joins & Dynamic filters
  • Group By / Aggregations
  • Large List processing
  • Aggregate optimization

7. Timers & Background Processing

  • Batch processing
  • Large-volume processing
  • Retry & failure handling
  • Idempotent Timers
  • Concurrent execution
  • Avoiding duplicate processing
  • Recovery mechanisms

8. Performance

  • Slow screen / Aggregate / API troubleshooting
  • Database optimization
  • Large data handling
  • Client-server communication
  • Monitoring & production troubleshooting

9. Security

  • Roles & Authorization
  • Server-side validation
  • API security
  • SQL Injection / XSS
  • Authentication vs Authorization
  • Sensitive data handling

10. Reactive UI

  • Form & Dynamic validation
  • Parent/Child communication
  • Screen lifecycle
  • Multiple data sources
  • Refresh & state management

11. Architecture

  • Layered architecture
  • Core / Service / UI responsibilities
  • Reusability
  • Dependency management
  • Circular dependencies
  • Coupling / Cohesion
  • Refactoring

12. Real-World ScenariosFocus especially on implementation scenarios such as:

  • Processing 20K+ records efficiently
  • Handling API failures and retries
  • Preventing duplicate Timer processing
  • Handling concurrent updates
  • Optimizing a screen loading thousands of records
  • Implementing audit/history
  • Designing scalable integrations
  • Troubleshooting production performance issues
UserImage.jpg
Rajkamal Singh Jhala

Thank u 

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