Jackson with Kotlin
JSON in production Kotlin with Jackson: the Kotlin module, annotations + @field:/@get: use-site targets, polymorphism over sealed classes, custom (de)serializers, and WebFlux.
- Step 1
Jackson ObjectMapper Basics with the Kotlin Module
One ObjectMapper plus jackson-module-kotlin turns your data classes into JSON and back, no boilerplate constructors required.
Read lesson - Step 2
Jackson Annotations in Kotlin: Shaping Your JSON
Master Jackson's core annotations and the one Kotlin use-site target gotcha that silently breaks your serialization.
Read lesson - Step 3
Polymorphic JSON with Jackson and Kotlin Sealed Types
Teach Jackson to round-trip your sealed-class ADTs with a single type discriminator field.
Read lesson - Step 4
Custom Jackson Serializers & Deserializers in Kotlin
When Jackson's defaults betray your domain types, hand-written JsonSerializer/JsonDeserializer pairs put you back in control of the wire format.
Read lesson - Step 5
Jackson Tree Model & Streaming API
When the shape is unknown, climb the tree; when the payload is enormous, ride the stream.
Read lesson - Step 6
Dates and Nulls with Jackson: java.time, Timestamps, and snake_case
Tame java.time, the null-versus-absent trap, and snake_case so your JSON is portable and predictable.
Read lesson - Step 7
Jackson in Spring WebFlux
In WebFlux, Jackson is the invisible engine that turns JSON into your data classes and back — until you need to bend it, and then you reach for one ObjectMapper bean.
Read lesson