youndie@kotlin.website:~/src$ cat mongkn/README.md

mongkn

kotlin/native · cinterop · mongodb
MongoDB for Kotlin/Native, where no official driver exists. A cinterop binding over libmongoc behind the shape of the coroutine driver's API — transactions, change streams, and read overhead indistinguishable from bare C.
github/mongknread the write-upall libraries

Why it exists

There is no official MongoDB driver for Kotlin/Native — mongodb-driver-kotlin-coroutine is JVM-only. mongkn writes the cinterop once and hides it behind suspend fun insertOne(…) and fun find(…): Flow<Document>.

What you get

  • 24 of 30 collection operations: insert, update, delete, find, aggregation, indexes, bulkWrite, findOneAnd*, distinct. The six missing are missing on purpose — five are Atlas Search index operations, which do not exist on a self-hosted server, and the sixth is mapReduce, deprecated by MongoDB itself.
  • Sessions and transactions, with withTransaction retrying on server error labels.
  • Change streams on collection, database and client, with automatic resumption.
  • All topologies: standalone, replica set, sharded through mongos. SCRAM, TLS and x509, verified against servers started with --auth and --tlsMode requireTLS.
  • 18 of 20 BSON types, its own tree model, and a kotlinx.serialization format on top.

Performance

Overhead over the C driver it wraps, from a release binary against a local mongo:8:
Write, per operation 1470 µs against 1492 µs for bare C — below the measurement threshold
Read into a class, per document 1.26 µs on Linux/x86_64, 1.66 µs on macOS/arm64
Read overhead over a bare C cursor loop −0.35 %, indistinguishable
kotlinx.serialization codec 0.27 µs, about 5 % of the mandatory conversion

Install

repositories { maven("https://reposilite.kotlin.website/snapshots") }
dependencies { implementation("io.github.youndie.mongkn:mongkn-core:<VERSION>") }

The write-up above is the one worth reading before you depend on this: four bugs that a full test suite and 71 specification scenarios did not catch, because none of them threw.

more
tracybooblikpetichmetrikkatchersmtpkn