CouchDB vs MongoDB:
A comparative study between CouchDB and MongoDB is presented below:
| CouchDB | MongoDB |
| Written in Erlang. | Written in C++. |
| Document-oriented model. | Document-oriented model. |
| Safer. | Less Safer. |
| Eventually consistent. | Strongly consistent. |
| Data is presented in JSON format. | Data is presented in BSON format. |
| Uses HTTP/REST based interface which is intuitive and well designed. | Uses binary protocol and custom protocol over TCP/IP. |
| Database contains documents. | Collection contains documents, and collections are stored in database. |
| Follows Map/Reduce query method. | Follows Map/Reduce creating collection plus object-based query language. |
| Supports master-master replication with custom conflict resolution functions. | Supports master-slave replication. |
| Follows MVCC or Multi Version Concurrency Control. | Concurrency: Update in-place. |
| Favors availability. | Favors consistency. |