I've finished migrating KtMongo from Kotest to TestBalloon. Some numbers that may be of interest; Protocol:

./gradlew clean; ./gradlew check; ./gradlew check --no-configuration-cache --rerun-tasks

•

clean

to ensure there aren't files left over •

check

to ensure everything needed is available locally (all dependencies are downloaded, etc) •

--no-configuration-cache

to ensure a fair execution order and disable intra-project parallelism •

--rerun-tasks

to disable incremental compilation, the build cache, up-to-date checks, etc • Only the last invokation is timed, using Gradle's build timer So: the test measures how long tests execute, but also how long it takes to compile, etc. The repository compiles to nearly all Kotlin targets using cross-compilation, so compilation time is quite a lot. Kotest: 2c899266a67a1c605e97d615afa353246859e261 • 2min 2s TestBalloon: 3dc162f411167345de9f38bd3c4cbb46569afa54 • 1min 2s That's a pretty big difference if you ask me!

KtMongo 0.19.0 is out! • Added multiplatform

ObjectId

and

Timestamp

• `BsonType.Datetime`is automatically interpreted as

kotlin.time.Instant

• Added the aggregation operators

$switch

,

$type

,

$isNumber

,… • Added the filter operators

$bitsAllClear

,… • Added the options

writeConcern

and

readPreference

• Added a new documentation section on aggregation support Full changelog

Prepared 2.1.0 is out! • Improved logging in failed tests with finalizers • Added

String.matches(String)

to simplify Regex-based assertions • Added

checkThrows

for easy exception-based tests • Deprecated the KotlinX.Datetime compatibility module (all related functionality has been merged into the main module using

kotlin.time

) • Stabilized the resource management APIs • Kotest 6.0.0.M4 and TestBalloon 0.4.0 support Full changelog

Hi! I've been working on a project similar to KtMongo for a while and I no longer have the time to maintain it by myself, so I'm looking into migrating to yours. A few questions, however: • does KtMongo automatically use SerialNames for filters/aggregations/etc? Having to name a property

_id

feels incorrect to me, so I prefer annotating it with

@SerialName("_id")

instead, along with other properties. • is the

Parent::child / Child::property

syntax the only way to refer to nested properties? Using the division operator feels very hacky, how difficult would it be to implement nesting like

Parent::child { Child::property eq ??? }

KtMongo 0.20.1 is out! • Added the update operators

$currentDate

and

$addToSet

• Added support for reading and writing

ObjectId

But also, the documentation website has been moved to https://ktmongo.opensavvy.dev/! Please share the link to help with SEO 🙏

Hi @CLOVIS. I'm testing your vite plugin and I'm not sure why the reload process is slow (slower than with webpack).

KtMongo 0.21.0 is out! • Added the

$group

stage and its

$sum

accumulator • Added the

$multiply

,

$divide

and

$subtract

aggregation operators • Added 12 aggregation operators for string management! Full changelog

Vite for Kotlin 0.6.1 is out! • Fixed "maximum call stack exceeded" on large projects • Fixed Vite always reloading all files in development mode, now Vite will only reload changed files, this speeds up reload times considerably https://vite-kotlin.opensavvy.dev/news/2025/08/29/v0.6.1.html

I've tested this new version and the .mjs files are correctly cached now. Still, even when using cache, loading a few hundreds of modules takes noticeable time. I don't think using "per-file" granularity with Vite will ever be a good idea 🙂 I'll continue my tests without this option.

In general the Vite plugin works great. I've tested it with one of my largest web apps (built with Kilua) and was able to reduce time from code change to browser refresh from ~12 to ~8 seconds. Still most of that time is Kotlin code compilation (~7 seconds). I use full HMR with webpack, so it's already a lot faster than standard webpack configuration. But I was able to configure full HMR for Vite plugin as well. It requires a bit different module loading and some changes in the application code. And I need to experiment a bit more with module disposal.

I need to keep compatibility with both webpack and vite and I've got a problem with resources paths. With webpack I use

@JsModule("/kotlin/css/style.css")

but with Vite I need

@JsModule("/css/style.css")

. I think the difference is in the directory where node command is executed. With webpack it's

build/js/packages/<module>

and

kotlin

is one level below. With vite it's

build/vite/dev/kotlin

. Could it be changed?

And could you remind me how to configure custom vite plugins? I tested that last year (https://gitlab.com/opensavvy/automation/kotlin-vite/-/issues/50) but I don't remember and can't find any docs.

I don't think using "per-file" granularity with Vite will ever be a good idea 🙂 I'll continue my tests without this option.

My understanding is that it is the use-case Vite aims to tackle...

With webpack I use

@JsModule("/kotlin/css/style.css")

but with Vite I need

@JsModule("/css/style.css")

.

I think so. It's this issue, if you want to follow it. I'll increase its priority. https://gitlab.com/opensavvy/automation/kotlin-vite/-/issues/39

The doc on Vite plugins is here: https://vite-kotlin.opensavvy.dev/api-docs/vite-base/opensavvy.gradle.vite.base.config/-vite-config/plugin.html

There is now a "getting started" configuration guide for the Vite plugin → https://vite-kotlin.opensavvy.dev/guides/

Where's KtMongo's BSON KotlinX serialization at? I need to use it or something like it soon.

Hi. In regards to wasmJs support (https://gitlab.com/opensavvy/automation/kotlin-vite/-/issues/46). I've played a bit with the sources and managed to modify the plugin to work with

wasmJs

target insted of

js

. The changes are really simple and wasm target works perfectly fine. I would be happy to contribute, but the problem is how to implement both js and wasmJs at the same time, considering that we can have only js, only wasmJs or both targets enabled in the same project. Do you have any suggestions how would you like this to work?

What is this path pointing at: https://gitlab.com/opensavvy/automation/kotlin-vite/-/blob/main/vite-kotlin/src/main/kotlin/tasks/ConfigWriter.kt#L23 ?

I'm trying to get along with tailwindcss vite plugin and it doesn't want to play nice 🙂 I think it adds

/src/**/*.kt

as files being watched. After every kt file change it reloads the application. And then Vite reloads again when compilation is finished. It is similar to this: https://github.com/tailwindlabs/tailwindcss/issues/16764 . Any idea if we can somehow "de-watch" files in vite?

For the same application webpack produces smaller JS bundle (webpack: 494KB, vite: 520KB). Perhaps some additional configuration of vite is needed?

I've published new Kilua template project with Vite plugin configured and ready to use (currently only for JS target). Full HMR with passing compose state to new cycle is implemented. You can compare the implementation with the standard, webpack based template. You can also compare the production bundles.

Could the vite plugin automatically modify standard

index.html

file to by compatible with it. The file is already copied to vite directory, just some simple regexp filtering would be enough in my opinion.

Dokka for MkDocs 0.5.3 is out! This release contains a bug fix for the Gradle

:clean

task and dependency updates. https://dokka-mkdocs.opensavvy.dev

What is the correct way to get the plugin configuration? I can't see anything I set inside

vite {}

block.

Is there any particular reason why you create copy tasks using

DefaultIncrementalSyncTask

class instead of standard

Copy

class?

Vite for Kotlin 0.6.3 is out! • The config file is now called

vite.config.mjs

by default (this allows using ES5 and ES6 plugins) • The app won't reload a first time anymore when the Kotlin code changes, it waits for the JS files to change too • The source maps are fixed for the current module • Removed an intermediary copy that happened between all reloads https://vite-kotlin.opensavvy.dev/news/2025/09/13/v0.6.3.html

Hi, you mentionned in June that “The Vite plugin is broken since K2”. I guess this newer 0.6.3 Version should work?

gitlab-ci.main.kts 0.7.1 is out! • Fixed some incorrect defaults with docker images, Pacman and Kaniko • Improved the documentation of artifacts https://gitlab-ci-kts.opensavvy.dev/news/2025/09/13/v0.7.1.html

Hey everyone! If you were at KTConf and are interested in KtMongo, this is the place to be! If you have any questions, don't hesitate to ask here. I'm currently searching for early adopters, ideally people who have codebases with high-quality tests, so they can help me figure out the best API shape, and detect edge cases I may have missed. See you next year there too!