ktor-server-examples

Standalone Ktor server examples built with Gradle, from a minimal hello-world service to a more feature-rich REST API sample.

What is in this repository

Module	Purpose
hello-world-server	Smallest possible Ktor server with one route, using the CIO engine
basic-server	REST API example using the CIO engine, with Koin DI, JSON serialization, logging, static resources, and status pages
advanced-server	Will include everything from basic-server, plus a real database using Exposed/PostgreSQL and JWT authentication (coming soon).

Prerequisites

• JDK 21 (modules set jvmToolchain(21))
• macOS/Linux/Windows
• Use the included Gradle wrapper (./gradlew or gradlew.bat)

Quick start

Run the hello-world module:

./gradlew :hello-world-server:run

Then call:

curl http://localhost:8080/api/v1/hello

Run modules

./gradlew :hello-world-server:run
./gradlew :basic-server:run

Both modules default to port 8080, so stop one before starting the other.

Useful API calls (basic-server)

curl http://localhost:8080/api/v1/users
curl http://localhost:8080/api/v1/users/<user-id>
curl http://localhost:8080/api/v1/products
curl "http://localhost:8080/api/v1/products?query=phone"

Build and test

./gradlew clean build
./gradlew test

Build artifacts are generated under each module's build/libs directory.

Project layout

• hello-world-server/: minimal embedded CIO example
• basic-server/: multi-feature API sample
• advanced-server/: advanced sample scaffold
• gradle/libs.versions.toml: centralized versions/plugins

Troubleshooting

• Port already in use: free port 8080 or change module config.
• Java version mismatch: check with java -version and use JDK 21.
• Gradle oddities: run ./gradlew --stop and retry.

License

See LICENSE.