Mastering GraphQL with Ktor: A Modern Networking Guide for Android

Originally published on Medium: https://medium.com/@supsabhi/mastering-graphql-with-ktor-a-modern-networking-guide-for-android-028f388836ed

Modern Android apps demand flexible, efficient and scalable networking solutions. While REST APIs have been the standard for years, GraphQL has emerged as a powerful alternative ,especially for apps that need precise data fetching and reduced network overhead. Instead of hitting multiple endpoints to get different pieces of data, GraphQL allows you to ask for exactly what you need in a single request.

In my previous article, I discussed how to set up Ktor, the modern Kotlin-first networking framework developed by JetBrains. We explored how it provides a lightweight alternative to Retrofit. If you haven’t read that yet, I highly recommend checking it out to get your base client set up.You can find the article here:

Exploring Ktor: A Modern Networking Framework for Kotlin:
https://medium.com/@supsabhi/exploring-ktor-a-modern-networking-framework-for-kotlin-462e6769a721

Now, let’s take things a step further and explore how you can integrate GraphQL with Ktor to build efficient APIs. Whether you are a beginner or looking to modernize your stack, this guide will cover everything from setup to making your first request.

What is GraphQL?
GraphQL is a query language for APIs that allows the client to request exactly the data it needs ,nothing more nothing less.

The major difference is that REST uses multiple endpoints with fixed response structures, while GraphQL uses a single endpoint with flexible queries to give optimized responses. This bandwidth efficiency is perfect for mobile apps where every kilobyte counts.

Why Use GraphQL with Ktor?
Using Ktor for GraphQL gives you:

Minimal Overhead: No need for heavy external libraries,keep your APK size small.
Full Control: You define exactly how the request and response are handled.
Multiplatform Ready: The same logic works seamlessly in Kotlin Multiplatform (KMP).
Kotlin-First: Coroutine-based, no callbacks, and works smoothly with Clean Architecture & MVVM

Setting Up the Project:
Before integrating GraphQL, ensure you have Ktor in your Android project. Add these dependencies to your app-level build.gradle.kts:

dependencies {
    implementation(platform("io.ktor:ktor-bom:3.1.2"))
    implementation("io.ktor:ktor-client-android")
    implementation("io.ktor:ktor-client-content-negotiation")
    implementation("io.ktor:ktor-serialization-kotlinx-json")
    implementation("io.ktor:ktor-client-logging")
}

Ensure the Kotlin Serialization plugin is enabled in your root build.gradle.kts:

plugins 
{
    id("org.jetbrains.kotlin.plugin.serialization") 
    version "2.1.20"
}

Understanding How GraphQL Works with Ktor
With GraphQL, every operation is usually a POST request to a single endpoint. The query or mutation is passed as a JSON body.

1. Define the Request Model First, create a data model to wrap your query:

@Serializable
data class GraphQLRequest(
    val query: String,
    val variables: Map<String, String>? = null
)

1. Define the Generic Response Wrapper GraphQL always returns data inside a data field and errors inside an errors field.

@Serializable
data class GraphQLResponse<T>(
    val data: T? = null,
    val errors: List<GraphQLError>? = null
)

@Serializable
data class GraphQLError(val message: String)

Making Your First Request
Let’s fetch a list of countries using a public GraphQL API. First, define your data models:

@Serializable
data class CountriesData(val countries: List<Country>)

@Serializable
data class Country(
    val code: String,
    val name: String,
    val emoji: String,
    val capital: String? = null
)

Implementation
Here is how you execute the query using the httpClient we created in the previous article:

suspend fun fetchCountries(): GraphQLResponse<CountriesData> {
    val countryQuery = """
        query {
            countries {
                code
                name
                emoji
                capital
            }
        }
    """.trimIndent()


return httpClient.post("https://countries.trevorblades.com/graphql") {
        setBody(GraphQLRequest(query = countryQuery))
    }.body()
}

Handling Errors and Logging
GraphQL can return an HTTP 200 status even if there are errors in the query logic. Always check the error list:

val response = fetchCountries()
if (!response.errors.isNullOrEmpty()) {
    response.errors.forEach { error ->
        Log.e("GraphQL Error", error.message)
    }
}

For professional logging, I recommend using Timber. I’ve written a detailed guide on setting it up here: Effortless Android Logging with Timber and Kotlin.:
https://medium.com/@supsabhi/effortless-android-logging-with-timber-and-kotlin-f0aaa0a701b7

Final Thoughts
Integrating GraphQL with Ktor is straightforward and gives Android developers a modern, flexible and Kotlin-native networking stack. It fits beautifully with MVVM and Clean Architecture. By leveraging one unified HttpClient, you can now handle both REST and GraphQL seamlessly.

GitHub Repository for Hands-On Reference
To make this article more practical and hands-on, I’ve published a public GitHub repository that demonstrates everything discussed above using a real GraphQL API.

The goal of this project is not just to “fetch data”, but to show how GraphQL should be integrated idiomatically in an Android application using Ktor, without forcing REST-based abstractions on top of it.
📂 GitHub Repository:

supsabhi / GraphQL_example

GraphQL Example – Android (Jetpack Compose + Ktor)

This project is a simple, clean Android sample demonstrating how to consume a GraphQL API using Ktor in a Jetpack Compose application, following Clean Architecture and MVVM principles.

The goal of this repository is to show idiomatic GraphQL handling in Android without REST-style abstractions like fake HTTP status codes or generic response wrappers.

---

✨ Features

• ✅ GraphQL API integration using Ktor
• ✅ Jetpack Compose UI
• ✅ Clean Architecture (Data → Domain → UI)
• ✅ MVVM with unidirectional data flow
• ✅ Kotlin Coroutines
• ✅ Koin for dependency injection
• ✅ Proper GraphQL error handling (data vs errors)
• ✅ No Retrofit, no REST-style CommonResponse

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🔗 API Used (Free & Public)

Countries GraphQL API

https://countries.trevorblades.com/graphql

Sample query:

query {
  countries {
    code
    name
    capital
  }
}

This API is:

• Completely free
• No authentication required
• Ideal for demos and learning

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🏗️ Architecture Overview

UI (Jetpack

…

View on GitHub