21 interview questions on RegEx for developers (2026)

Medium

5 votes196 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 votes219 runs0 comment

Which of the following is not a regular expression?

Back-end developer

RegEx

characters

Anonymous authorat Mar 28, 2023

Expert

3 votes169 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 votes201 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 votes199 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 votes194 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 votes177 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 votes174 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 vote197 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 vote186 runs0 comment

Write a regular expression to match the characters . and ?

Back-end developer

RegEx

characters

Anonymous authorat Mar 28, 2023

Medium

1 vote181 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 vote174 runs0 comment

Write a regular expression that matches a valid email address

Back-end developer

RegEx

email

Anonymous authorat Mar 28, 2023

Medium

1 vote169 runs0 comment

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

Back-end developer

RegEx

file

Anonymous authorat Mar 28, 2023

Easy

1 vote163 runs0 comment

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

Back-end developer

RegEx

regular expressions

character classes

Anonymous authorat Mar 28, 2023

Medium

1 vote145 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 vote7 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 vote7 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 vote168 runs1 comment

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

Back-end developer

RegEx

characters

Anonymous authorat Feb 6, 2024

Easy

0 vote95 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`