Schemaless mode is used when we want to quickly create a useful schema by indexing sample data. It does not involve any manual editing of the data.

All of its features are managed by solrconfig.xml.

The features that we are particularly interested in are:

• Managed schema: All modifications in the schema are made via Solr API at runtime using schemaFactory, which supports these changes.
• Field value class guessing: This is a technique of using a cascading set of parsers on fields that have not been seen before. It then guesses whether the field is an Integer, Long, Float, Double, Boolean, or Date.

And finally used for automatic schema field addition that is based on field value classes.