Serialization

In the previous tutorial, we built routes that return plain text. But real APIs use JSON. Clients send JSON requests and expect JSON responses. In this tutorial, you will add JSON serialization to your Ktor API using kotlinx.serialization — the official Kotlin serialization library. What is Content Negotiation? When a client sends a request, it tells the server what format it wants using the Accept header. When it sends data, it uses the Content-Type header. ...

In the previous tutorial, you learned about Kotlin DSLs. Now let’s learn about Kotlin Serialization. Serialization is the process of converting objects to a format like JSON, and deserialization is the reverse. Kotlin Serialization is the official library for this. In this tutorial, you will learn: Setting up Kotlin Serialization @Serializable and basic encoding/decoding Default values and optional fields @Transient for ignoring fields @SerialName for custom field names Nested objects and collections Enum serialization Json configuration options Polymorphic serialization JsonElement API for raw JSON Practical examples Setting Up Add the serialization plugin and dependency to your build.gradle.kts: ...