Search Syntax

Search syntax for finding keywords and phrases is pretty universal and similar to searching on Google. Advanced querying syntax supported by PDF Highlighter is most similar to Apache Solr and Elasticsearch search engines.

Simple search

tax return

Search for an exact phrase

To lookup for a phrase, enclose multiple words in quotation marks.

"tax return"

Proximity search

Proximity search allows you to find words near to each other within specified distance.

"acknowledgment message"~5

To find words acknowledgment and message within 5 words of each other.

Search using wildcards

Use * to matches any group of characters, or ? for a single character.


Searches for documents containing any word starting with the letters qual, such as qualify, quality, qualification, qualifier, and so forth.

Fuzzy search

To perform a fuzzy search, use the tilde ~ symbol at the end of a single-word term.


This search will match terms like roams, foam, & foams. It will also match the word "roam" itself.

An optional distance parameter specifies the maximum number of edits allowed, between 0 and 2, defaulting to 2. For example:


This will match terms like roams & foam - but not foams since it has an edit distance of "2".

NOTE: If fuzzy search is enabled globally, it will apply to all keyword searches without need to use the tilde symbol.

Boolean expressions, positive and negative terms

PDF Highlighter supports Boolean expressions, as well as positive and negative terms, with some specifics. Considering that a typical use case for PDF Highlighter is highlighting of documents that already matched user's document search request, it's generally safe to pass the same query to PDF Highlighter for document processing. All keywords which are not specifically excluded (with a "NOT" or with "-") will be highlighted.


If language is defined, PDF Highlighter automatically enables stemming. Stemming is a text analysis technique that allows you to find word variations. It means that if you search for term qualification search engine will also find documents with terms qualify, qualifier, etc.

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