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Alex Rupérez

Published: 07 Jun 13:40
I starred 47deg/helios at GitHub.
A purely functional JSON library for Kotlin built on Λrrow -
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Helios is a library used to transform Json text into a model and vice versa. It's based on a part of the Jawn Parser built on Arrow, a Functional companion to Kotlin's Standard Library.

Adding the dependency

Helios uses kotlin 1.3.10 version and Arrow 0.8.1 version.

To import the library on Gradle add the following repository and dependencies:

repositories {
      maven { url "" }
dependencies {
    compile "com.47deg:helios-core:0.0.1-SNAPSHOT"
    compile "com.47deg:helios-meta:0.0.1-SNAPSHOT"
    compile "com.47deg:helios-parser:0.0.1-SNAPSHOT"


You can find a quick-start here.

Why Helios

Helios is the one of the fastest Json parser library on Kotlin with the advantage of the Arrow functional programming


Library Score Score Error (99.9%) Unit
helios 19032.522733 1511.699343 ops/s
jackson 32247.369607 2506.006530 ops/s
klaxon 571.281780 14.468980 ops/s
kotson 29600.046472 632.968692 ops/s
moshi 33326.678828 1062.384473 ops/s


Library Score Score Error (99.9%) Unit
helios 9334.929365 7684.760121 ops/s
jackson 23789.397621 2854.291651 ops/s
klaxon 452.653645 79.123214 ops/s
kotlinx 38650.988483 2198.522152 ops/s
kotson 38081.187808 952.164481 ops/s
moshi 25571.429371 1157.867183 ops/s


Library Score Score Error (99.9%) Unit
helios 29960.715221 2098.828841 ops/s
jackson 42058.986030 3536.245777 ops/s
jsonIter 33036.995781 515.394397 ops/s
kotson 29249.670413 2863.133433 ops/s
moshi 19017.079668 1202.955223 ops/s

Running Benchmarks

To run the benchmarks execute the following command:

./gradlew :helios-benchmarks:jmh -PjmhInclude=helios.benchmarks.HeliosBenchmark