Solulab inc Backend Developer Interview Questions and Answers

Faced a challenge with database performance, optimized queries, and implemented caching to enhance response times significantly.

• Identified slow queries using profiling tools like EXPLAIN in SQL.

• Refactored complex joins into simpler queries to reduce execution time.

• Implemented Redis caching for frequently accessed data, reducing database load.

• Monitored performance metrics post-implementation to ensure improvements.

Ensuring backend security and scalability involves implementing best practices in architecture, coding, and infrastructure management.

• Implement authentication and authorization mechanisms (e.g., OAuth, JWT) to secure APIs.

• Use HTTPS to encrypt data in transit and protect against man-in-the-middle attacks.

• Regularly update dependencies and libraries to patch known vulnerabilities.

• Employ rate limiting and throttling to pre...read more

I optimize databases by analyzing queries, indexing, and using caching strategies to enhance performance in large-scale applications.

• Analyze slow queries using tools like EXPLAIN to identify bottlenecks.

• Implement indexing on frequently queried columns to speed up data retrieval.

• Use caching mechanisms (e.g., Redis, Memcached) to reduce database load.

• Partition large tables to improve query performance and manageability.

• O...read more

Database indexing improves query performance by reducing the number of disk I/O operations needed to retrieve data.

• Indexing allows the database to quickly locate specific rows in a table, reducing the need to scan the entire table.

• Indexes can be created on columns frequently used in WHERE clauses or JOIN conditions.

• Examples of indexes include primary keys, unique constraints, and composite indexes.

• Proper indexing can s

REST API in backend development is used to allow communication between different systems over the internet.

• Allows for communication between different systems or services

• Follows a client-server architecture

• Uses standard HTTP methods like GET, POST, PUT, DELETE

• Supports multiple data formats like JSON, XML

• Stateless, meaning each request from a client must contain all the information needed to fulfill the request

GET method is used to request data from a server, while POST method is used to submit data to a server in HTTPS.

• GET requests data from a specified resource, while POST submits data to be processed to a specified resource.

• GET requests can be cached and remain in the browser history, while POST requests are not cached and do not remain in the browser history.

• GET requests have length restrictions on the amount of data tha...read more

GET is used to retrieve data from a server, while POST is used to send data to a server.

• GET requests are used to retrieve data from a specified resource. For example, fetching a list of products from an online store.

• POST requests are used to submit data to be processed by a server. For example, submitting a form with user information to create a new account.

• GET requests are idempotent, meaning they can be repeated mult...read more

Android language is used in developing applications for Android devices.

• Android language, such as Java or Kotlin, is used to develop mobile applications for Android devices

• Android language is used to create user interfaces, handle data storage, and implement functionality in Android apps

• Developers can use Android Studio, an official IDE for Android development, to write and test their code