A lightweight Kotlin Multiplatform (KMP) library for parsing the payload section of a JWT token on both Android and iOS.

It provides a simple API to decode JWT payloads into a Kotlin object using kotlinx.serialization.

• Kotlin Multiplatform support (Android / iOS)
• Simple JWT payload parsing
• Built with kotlinx.serialization
• Access standard JWT claims easily
• Safely read custom claims with helper extensions

The library is published on Maven Central.

[versions]
simpleJwtParser = "2.0.0"

[libraries]
simpleJwtParser = { module = "io.github.jmseb3:simpleJwtParser", version.ref = "simpleJwtParser" }

Then add the dependency:

kotlin {
    sourceSets {
        val commonMain by getting {
            dependencies {
                implementation(libs.simpleJwtParser)
            }
        }
    }
}

kotlin {
    sourceSets {
        val commonMain by getting {
            dependencies {
                implementation("io.github.jmseb3:simpleJwtParser:2.0.0")
            }
        }
    }
}

Use JwtParser.parseToJsonObject() to parse the payload section of a JWT token into a Payload object.

val payload: Payload = JwtParser.parseToJsonObject(jwtToken)

The Payload class supports the default JWT claims:

• iss — Issuer
• sub — Subject
• aud — Audience
• exp — Expiration Time
• nbf — Not Before
• iat — Issued At
• jti — JWT ID

You can also access custom claims using the get() function.

val loginType = payload.get(
    key = "member_login_type",
    defaultValue = ""
)

The library provides safe extension methods for JsonObject.

val typeOfLogin: String? =
    jsonObject
        .safeGet("member_login_type")
        ?.jsonPrimitive
        ?.content

val typeOfLogin: String =
    jsonObject
        .safeGet(
            key = "member_login_type",
            defaultValue = ""
        )
        .jsonPrimitive
        .content

• Kotlin Multiplatform
• kotlinx.serialization

Licensed under the Apache License 2.0.

See the LICENSE file for details.