21 interview questions on RegEx for developers (2026)

Medium

5 votes195 runs2 comments

Find all the strings that match the regular expression: `/abracadabra{2,4}/gmi`

Back-end developer

RegEx

pattern

Anonymous authorat Mar 28, 2023

Easy

4 votes218 runs0 comment

Which of the following is not a regular expression?

Back-end developer

RegEx

characters

Anonymous authorat Mar 28, 2023

Expert

3 votes168 runs1 comment

Write a regular expression to extract a file name from a path, except if the file is a .html file

Back-end developer

RegEx

file

Anonymous authorat Mar 28, 2023

Medium

2 votes200 runs0 comment

Write a RegEx that has the same behavior as trim (JS) or strip(Python)

Back-end developer

RegEx

functions

Anonymous authorat Mar 28, 2023

Easy

2 votes198 runs0 comment

Write a regular expression that matches a character that repeats exactly 6 times.

Back-end developer

RegEx

character

Nick LAM YEE MANat May 16, 2023

Medium

2 votes193 runs0 comment

Write a regular expression that matches anything that looks like an HTML tag.

Back-end developer

RegEx

html

Anonymous authorat Mar 28, 2023

Medium

2 votes176 runs0 comment

Write a RegEx that will only find the word 'test' in the sentence 'I write a testimonial about this test'

Back-end developer

RegEx

pattern

Anonymous authorat Mar 28, 2023

Easy

2 votes173 runs0 comment

Find the intruder in the following regex: `^[a-zA-Z0-9_-]+$`

Back-end developer

RegEx

pattern

Anonymous authorat Mar 28, 2023

Medium

1 vote196 runs0 comment

Write a regular expression that matches any number in a string

Back-end developer

RegEx

pattern

Anonymous authorat Mar 28, 2023

Medium

1 vote185 runs0 comment

Write a regular expression to match the characters . and ?

Back-end developer

RegEx

characters

Anonymous authorat Mar 28, 2023

Medium

1 vote180 runs0 comment

Write a regular expression that replaces all tags without content with self-closing tags

Back-end developer

RegEx

Find all the occurrences of the substring 'abracadabra' in the string 'abracadabraabracadabraabracadabra'

Back-end developer

RegEx

quantifiers

Anonymous authorat Mar 28, 2023

Medium

1 vote173 runs0 comment

Write a regular expression that matches a valid email address

Back-end developer

RegEx

email

Anonymous authorat Mar 28, 2023

Medium

1 vote168 runs0 comment

What does this RegEx do : `/(^\w+)(?=\.\w+)/old_$1/gm`

Back-end developer

RegEx

file

Anonymous authorat Mar 28, 2023

Easy

1 vote162 runs0 comment

What does the RegEx `/[abc]/` match

Back-end developer

RegEx

regular expressions

character classes

Anonymous authorat Mar 28, 2023

Medium

1 vote143 runs

1 comment

Which RegEx(s) can be used to verify that a password meets these criteria: - at least 1 (one) lowercase letter - at least 1 (one) uppercase letter - at least 1 (one) number - at least 8 (eight) characters

Back-end developer

RegEx

password

Anonymous authorat Mar 28, 2023

Hard

1 vote6 runs0 comment

Count the number of matches of the RegEx `a*` in the sentence: `I went to my grandparent house`

Back-end developer

RegEx

string

Matthieu Sanchezat Feb 2, 2026

Medium

1 vote6 runs0 comment

Write a regular expression to match 'i{,4}' in a string

Back-end developer

RegEx

pattern

Matthieu Sanchezat Feb 2, 2026

Hard

0 vote167 runs1 comment

Which letters will be match by the RegEx `/\x42/gmi`

Back-end developer

RegEx

characters

Anonymous authorat Feb 6, 2024

Easy

0 vote94 runs0 comment

Write a regular expression that matches anything that is not `a`, `b` or `c`

Back-end developer

RegEx

character classes

Anonymous authorat Mar 28, 2023

21 interview questions on RegExfor developers (2026)

Test your technical skills before an interview of RegEx with 21 corrected questions. Beginner, Intermediate or Expert level.

Find all the strings that match the regular expression: `/abracadabra{2,4}/gmi`

Which of the following is not a regular expression?

Write a regular expression to extract a file name from a path, except if the file is a .html file

Write a RegEx that has the same behavior as trim (JS) or strip(Python)

Write a regular expression that matches a character that repeats exactly 6 times.

Write a regular expression that matches anything that looks like an HTML tag.

Write a RegEx that will only find the word 'test' in the sentence 'I write a testimonial about this test'

Find the intruder in the following regex: `^[a-zA-Z0-9_-]+$`

Write a regular expression that matches any number in a string

Write a regular expression to match the characters . and ?

Write a regular expression that replaces all tags without content with self-closing tags

Find all the occurrences of the substring 'abracadabra' in the string 'abracadabraabracadabraabracadabra'

Write a regular expression that matches a valid email address

What does this RegEx do : `/(^\w+)(?=\.\w+)/old_$1/gm`

What does the RegEx `/[abc]/` match

Which RegEx(s) can be used to verify that a password meets these criteria: - at least 1 (one) lowercase letter - at least 1 (one) uppercase letter - at least 1 (one) number - at least 8 (eight) characters

Count the number of matches of the RegEx `a*` in the sentence: `I went to my grandparent house`

Write a regular expression to match 'i{,4}' in a string

Which letters will be match by the RegEx `/\x42/gmi`

Write a regular expression that matches anything that is not `a`, `b` or `c`