Prisma 2.27 introduces preview support for MongoDB, the most requested feature since Prisma 2's release. The integration brings type safety to MongoDB by allowing developers to define a schema using Prisma Schema, from which a TypeScript Prisma Client is auto-generated. This enables type-safe queries against MongoDB collections. Current limitations include no Prisma Migrate support, no introspection, limited embedded document support, and a requirement for replica sets when using transactions. The release is not production-ready and the team is seeking community feedback before general availability.