NeDB

The README explicitly warns that the project is no longer maintained, meaning no bug fixes, security patches, or updates, which poses risks for production use.

Only implements a subset of MongoDB's API, missing operators like $text for full-text search and advanced features such as aggregation, restricting complex data operations.

For file-based storage, developers must manually call loadDatabase or rely on autoload, adding setup complexity compared to databases that auto-initialize.

Benchmarks show it's fast for small datasets, but the in-memory model and append-only persistence can become inefficient with large volumes or high concurrency.