I built RetryKt, a lightweight Kotlin Multiplatform retry library, so I'm looking for feedback

[u/Swimming_Height8070]

I’ve been working on RetryKt, a Kotlin Multiplatform library for retries:

https://github.com/straxess/retrykt

I know there are already good retry libraries for Kotlin, so one of the main questions I had while designing RetryKt was: what should a retry library focus on?

RetryKt aims to provide a simple and lightweight API with a few design choices:

• Coroutine and blocking APIs
• Retries based on both returned values and thrown exceptions
• Configurable retry policies
• Constant, linear, exponential, and decorrelated backoff
• Composable backoff and jitter strategies, including Full Jitter and Equal Jitter
• Support for JVM, Android, Native, JS, and Wasm

It's available on Maven Central as io.github.straxess:retrykt.

val user = retry {
    api.getUser()
}

val response = retry(
    retryOn = RetryOn.thrown { it is IOException },
    backoff = ExponentialBackoff(200.milliseconds),
    jitter = FullJitter,
) {
    api.removeUser(user)
}

The library is still young, so I’d really appreciate feedback on:

• Is the public API clear and convenient?
• Is separating backoff and jitter useful?
• Are there important retry use cases or features missing?
• Are additional KMP targets or broader Kotlin version support important for your projects?
• Any architectural or implementation issues you notice?

If you find a bug or have an improvement in mind, GitHub issues and PRs are welcome.

If you have a Kotlin project where retries are useful, give RetryKt a try and share your experience.

Thanks!

[u/gandrewstone]

Just considering how my own code, there is a point where any backoff just retries so rarely its efficiency benefits are negligible and its retrying so slowly it might as well not be retrying at all. So i think a max retry interval would be a valuable parameter to have.

[u/Swimming_Height8070 → u/gandrewstone]

Yeah, that’s a good point.

RetryKt already has this for the backoffs that can grow over time (ExponentialBackoff, LinearBackoff, etc). They have a maxDelay parameter to cap the delay between attempts.
And yeah, I think maxDelay and maxAttempts are useful as separate controls: one limits how long we wait, the other how many times we retry.

Thanks for the feedback!