This developer-focused guide explores the process of migrating an application's data store from MongoDB to Couchbase Server, detailing considerations such as differences in data models, query languages, scaling models, and concurrency mechanisms between the two systems. It highlights key transitions, such as moving from BSON to JSON, leveraging Couchbase's N1QL for querying, and adopting hash-based sharding for simplified scaling. The guide also discusses Couchbase's distinct approach to replication and consistency, emphasizing its automatic sharding and indexing capabilities, and the necessity of redefining document namespaces through key naming and document types. It outlines the advantages of Couchbase's distributed master-master scaling compared to MongoDB's master-slave model while pointing out the importance of adapting bucket usage and indexing to optimize resource allocation and performance. The text concludes by encouraging developers to replace collection namespacing with key naming, utilize N1QL JOINs for query simplification, and consider the appropriateness of key-value access in their migration strategy.