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Regular Expressions

A regular expression (shortened as regex or regexp also referred to as regular expression) is a sequence of characters that specifies a search pattern.

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I ran my file-type detector over 8,900 real files. It was wrong in ways no test suite would have told me

I ran my file-type detector over 8,900 real files. It was wrong in ways no test suite would have told me

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16 min read
Regular Expressions Without the Fear

Regular Expressions Without the Fear

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3 min read
Regular Expressions Without the Fear

Regular Expressions Without the Fear

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3 min read
I scraped 89 job postings to find out how my salary parser was lying to me

I scraped 89 job postings to find out how my salary parser was lying to me

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9 min read
Four filters returned nothing and I read all four as nothing being there

Four filters returned nothing and I read all four as nothing being there

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3 min read
Stop Guessing: A Free Regex Tester That Actually Explains Your Pattern

Stop Guessing: A Free Regex Tester That Actually Explains Your Pattern

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3 min read
Regex Against a PDF: The One Endpoint That Skips OCR Entirely

Regex Against a PDF: The One Endpoint That Skips OCR Entirely

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6 min read
The Regex That Took Down Cloudflare for 27 Minutes

The Regex That Took Down Cloudflare for 27 Minutes

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2 min read
Debugging a 41-second regex hang with a regex tester in 2026

Debugging a 41-second regex hang with a regex tester in 2026

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6 min read
I built a ReDoS scanner that proves each bug offline — and hands you a verified fix

I built a ReDoS scanner that proves each bug offline — and hands you a verified fix

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5 min read
An unquoted heredoc halved my backslashes and turned a character class into the letter w

An unquoted heredoc halved my backslashes and turned a character class into the letter w

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4 min read
Stop letting your AI guess: The case for deterministic Regex in MCP

Stop letting your AI guess: The case for deterministic Regex in MCP

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4 min read
Parsing Trading Data With Regex: Test a Whole Suite of Cases at Once, Not One String

Parsing Trading Data With Regex: Test a Whole Suite of Cases at Once, Not One String

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4 min read
The Regex Bug That Passes Code Review, Passes Tests, and Takes Down Prod

The Regex Bug That Passes Code Review, Passes Tests, and Takes Down Prod

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6 min read
3 Regex Patterns That Save Hours of Debugging

3 Regex Patterns That Save Hours of Debugging

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2 min read
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