Elasticsearch, a powerful search and analytics engine, can be both impressive and frustrating due to its complex nature, prompting Logz.io to compile a cheat sheet of commonly used API calls to address frequent issues. Elasticsearch offers a set of APIs to modify settings at runtime, categorized into cluster, node, or index contexts. Changes can be transient, which do not persist after a cluster restart, or persistent, which do, with transient changes overriding persistent ones. The cheat sheet features various cURL commands for managing indices, querying data, and adjusting cluster settings, such as moving shards, forcing shard allocation, removing nodes, and optimizing recovery speeds. It also includes commands for clearing caches, adjusting circuit breakers, and checking cluster health, providing practical solutions to common challenges faced by Elasticsearch users.