[[analysis-charfilters]]
== Character Filters

Character filters are used to preprocess the string of 
characters before it is passed to the <<analysis-tokenizers,tokenizer>>.
A character filter may be used to strip out HTML markup, or to convert
`"&"` characters to the word `"and"`.    

Elasticsearch has built in characters filters which can be
used to build <<analysis-custom-analyzer,custom analyzers>>.

include::charfilters/mapping-charfilter.asciidoc[]

include::charfilters/htmlstrip-charfilter.asciidoc[]

include::charfilters/pattern-replace-charfilter.asciidoc[]
