Google Custom Search API enables you to develop websites and applications that retrieve and display search results from Programmable Search Engine programmatically. The API uses RESTful queries to obtain web search results or image search results in JSON format. Google Custom Search API provides 100 free queries per day to get started, with additional queries costing $5 per 1,000 requests up to a maximum of 10,000 queries per day. The platform requires a Search Engine ID and API key for authentication, with comprehensive setup guides available for creating and configuring your Programmable Search Engine. The API follows the OpenSearch 1.1 specification and provides structured JSON responses for easy integration. Google offers basic monitoring through the Cloud Platform API dashboard, with advanced monitoring available through Google Cloud Operations suite for custom dashboards, alerts, and automated metric data access. The platform is ideal for developers building search-enabled applications, content discovery features, or competitive analysis tools that need access to Google's comprehensive search index and advanced algorithms.