Apache Solr is an open source search platform built on a Java library called Lucene. It serves as a search platform for many websites, as it has the capability of indexing and searching multiple websites to fetch desired results.We begin with a brief introduction of analyzers and tokenizers to understand the challenges associated with implementing large-scale indexing and multilingual search functionality. We then move on to working with custom queries and understanding how filters work internally. While doing so, we also create our own query language or Solr plugin that does proximity searches. Furthermore, we discuss how Solr can be used for real-time analytics and tackle problems faced during its implementation in e-commerce search. We then dive deep into the spatial features such as indexing strategies and search/filtering strategies for a spatial search. We also do an in-depth analysis of problems faced in an ad serving platform and how Solr can be used to solve these problems.