Painless is a new scripting language introduced in Elasticsearch 5.0, designed for security and performance, developed due to the challenges of securing existing languages for remote execution. Created by Jack Conradson and team, Painless features syntax similar to Groovy and supports dynamic and static types, lambda expressions, and built-in regular expressions, with performance comparable to Java. It employs method and field-level whitelisting for stringent execution control and can be used anywhere in Elasticsearch where scripts run by specifying the 'lang' parameter as 'painless.' As the default language in Elasticsearch 5.0, Painless also allows for efficient scoring scripts and has been enhanced by contributions from Robert Muir, Uwe Schindler, and Nik Everett. Conradson, having previously worked on the Expressions language at A9.com, continues to improve scripting at Elasticsearch.