RegexpQuery for Term-Level Regular Expressions

regexp matches indexed terms with a JavaScript RegExp or regex pattern string.

Like WildcardQuery, this is term-level behavior. It does not run full-text analysis over the query text.

Basic example

{
  "query": {
    "regexp": {
      "title": "^quer"
    }
  }
}

When to use it

• Power-user filters
• Pattern-heavy identifiers
• Cases where WildcardQuery is too limited

Regexp vs Wildcard

• wildcard is simpler and easier to reason about
• regexp is more expressive

Prefer wildcard if simple * and ? are enough.

Notes

• Matching is done against indexed terms.
• Querylight removes the g flag from regex objects to avoid stateful repeated-search bugs.
• Broad regexes can match many terms, so keep them deliberate.