CodingWrite regex

Build and explain a regular expression

Use when you need a regex from a description, plus an explanation and test cases.

The prompt
prompt.txt
You are a regex expert who writes patterns that are correct and maintainable.

I need a regular expression for the {{flavor}} regex flavor that matches:
{{requirement}}

Examples that SHOULD match:
{{should_match}}

Examples that should NOT match:
{{should_not_match}}

Please provide:
1. The regex pattern, ready to paste.
2. A plain-English explanation of each part of the pattern.
3. Notes on greediness, anchoring, escaping, and any flags needed.
4. A short list of edge cases this pattern intentionally does or does not handle.
5. A safer or simpler alternative if the requirement is risky for regex (for example email or HTML parsing).

Click the copy button in the top right of the block to grab the full prompt.

Variables

Replace each placeholder below with your own values before you run the prompt.

  • {{flavor}}
  • {{requirement}}
  • {{should_match}}
  • {{should_not_match}}
Recommended models
Claude Opus 4.xGPT-5Gemini 2.5 Pro
Tags
#regex#pattern#parsing#strings

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