1657 interview questions for Back-end developer (2025)

Medium

106 votes4058 runs

6 comments

Understanding the differences between `map()` and `forEach()` methods in JavaScript

Web developer

Vincent Cotroat Jan 18, 2024

Medium

47 votes3717 runs4 comments

Write a JavaScript function that fetches data from an API and logs it to the console.

Web developer

promises

async

Vincent Cotroat Mar 28, 2023

Easy

47 votes3302 runs0 comment

Write a SQL query to retrieve the list of employees with a salary greater than 5100.

Back-end developer

sql

select

where

Vincent Cotroat Mar 30, 2023

Easy

38 votes1974 runs1 comment

Write a Python function that returns the factorial of a number.

Back-end developer

recursion

Vincent Cotroat Mar 28, 2023

Easy

34 votes2064 runs1 comment

Explain the difference between the `include` and `require` functions in PHP.

Back-end developer

functions

errors

Vincent Cotroat Mar 24, 2023

Easy

32 votes2985 runs

12 comments

Write a Java program that prints 'welovedev'.

Full stack developer

strings

variables

Pierreat Sep 19, 2022

Easy

28 votes3824 runs

2 comments

Fix the following Javascript loop:

Web developer

loops

conditions

Anonymous authorat Apr 27, 2023

Easy

24 votes798 runs1 comment

What is the purpose of the Laravel Sanctum tool?

Web developer

laravel

authentication

Damienat Sep 6, 2023

Hard

23 votes2359 runs0 comment

Write a Python function that prints the elements of a list.

Back-end developer

list

for loop

Anonymous authorat Mar 28, 2022

Easy

19 votes3253 runs0 comment

Select only distinct values in a column using SQL

Back-end developer

sql

distinct

Vincent Cotroat Mar 27, 2023

Easy

18 votes3166 runs1 comment

Update a column in an SQL table

Back-end developer

sql

update

Vincent Cotroat Nov 7, 2023

Easy

17 votes3271 runs0 comment

Write a SQL query to insert data into a table

Back-end developer

sql

insert

Vincent Cotroat Mar 27, 2023

Medium

16 votes3442 runs

1 comment

How many times is the condition `(a++ < 15)` evaluated in the following code? ```java int a = 3; while (a++ < 15) { if ((a++ % 5) == 0) break; } ```

Back-end developer

loops

control flow

Thomas De verdièreat Dec 16, 2021

Easy

16 votes3233 runs0 comment

Which SQL keyword is used to sort the result of a SELECT statement?

Back-end developer

sql

order by

Vincent Cotroat Mar 27, 2023

Medium

16 votes2777 runs0 comment

Explain the prototype scope in Spring

Back-end developer

spring

bean

Anonymous authorat Dec 21, 2021

Medium

15 votes2834 runs2 comments

A bean with a `session` scope is injected into a bean with a` singleton` scope. What happens when the application starts?

Back-end developer

spring

scope

Anonymous authorat Dec 21, 2021

Easy

14 votes3694 runs1 comment

What is the minimum PHP version for Symfony 5?

Back-end developer

php

symfony

Smaïne Millaniat Dec 3, 2021

Medium

14 votes1607 runs

1 comment

What is the difference between an interface and an abstract class in Java?

Full stack developer

EL Mostafa Fadiliat Feb 13, 2024

Easy

13 votes4002 runs

1 comment

Write a Javascript code that displays 'Adversity is not to be feared' and 'There is potentially a real danger'

Web developer

booleans

conditionals

Adrienat Mar 30, 2022

Hard

13 votes3445 runs1 comment

Serialization can be customized with the Externalizable interface

Back-end developer

serialization

interface

Thomas De verdièreat Jan 4, 2022

1657 interview questionsfor Back-end developer (2025)

Test your technical skills before an interview of Back-end developer with 1657 corrected questions. Beginner, Intermediate or Expert level.

Understanding the differences between `map()` and `forEach()` methods in JavaScript

Write a JavaScript function that fetches data from an API and logs it to the console.

Write a SQL query to retrieve the list of employees with a salary greater than 5100.

Write a Python function that returns the factorial of a number.

Explain the difference between the `include` and `require` functions in PHP.

Write a Java program that prints 'welovedev'.

Fix the following Javascript loop:

What is the purpose of the Laravel Sanctum tool?

Write a Python function that prints the elements of a list.

Select only distinct values in a column using SQL

Update a column in an SQL table

Write a SQL query to insert data into a table

How many times is the condition `(a++ < 15)` evaluated in the following code? ```java int a = 3; while (a++ < 15) { if ((a++ % 5) == 0) break; } ```

Which SQL keyword is used to sort the result of a SELECT statement?

Explain the prototype scope in Spring

A bean with a `session` scope is injected into a bean with a` singleton` scope. What happens when the application starts?

What is the minimum PHP version for Symfony 5?

What is the difference between an interface and an abstract class in Java?

Write a Javascript code that displays 'Adversity is not to be feared' and 'There is potentially a real danger'

Serialization can be customized with the Externalizable interface