Build Modern Android App with REST API and Ktor Server

Manually create a Kotlin Ktor project in IntelliJ with Gradle Kotlin DSL, add Netty and Logback dependencies, and expose a hello world route.

Learn to generate a Ktor project with a few clicks using the start.cater.io project generator, selecting build system, server engine, and routing plugins for a backend server.

Compare cater server engines—netty, jetty, tomcat, and coroutine-based io—and contrast engine main with embedded server, including hocon config and code-based setup for testing endpoints.

Learn how to organize a Ktor server into multiple modules using extension functions on the application class, each with its own routes and plugins, such as a /book endpoint.

Learn how to serve static content such as html, text, and images using a static function and a resources directory, with optional remote paths like assets.

Install and configure Ktor plugins, including call logging, content negotiation with json serialization, and routing via application class extension functions, plus coin and default headers with a cache control header.

Create the all heroes endpoint for the boruto app using Koin for dependency injection, with a cache-control header, and implement page query validation and API responses.

Develop and test the all heroes endpoint at boruto/heroes, which paginates 15 heroes across five pages using a page query, with page validation and previous/next page calculations.

Explore how to install and configure the status pages plugin in a Ktor server, map exceptions and status codes to custom responses, including 404 and 500.

Set up a new Android Studio project with an empty compose activity and configure dependencies for navigation, retrofit, room, and serialization. Outline splash, onboarding, home, search, and detail screens.

Define hero dao with dao and query annotations to read all heroes, fetch by id, and support insert and delete via burrito database using room and paging source.

Configure Dagger Hilt to provide a singleton room database builder across the app with a database module, and annotate the application and main activity for injection.

Save the onboarding state when the user finishes the welcome flow. Navigate from splash to home or welcome screens using a welcome view model, Hilt, and use cases.

Create the API response model with serializable annotation and implement Boruto API endpoints for getting all heroes with a page parameter and for searching by name.

Explore the paging three library for Android, paginate data from room databases or APIs, load pages on scroll, and apply paging config, pager, and map and filter operations.

Implement the remote mediator and load() for paging, handling refresh, prepend, and append, while fetching remote keys and caching hero data from the Boruto API.

Implement the get all heroes use case wired to the repository and remote data source, returning a flow of paging data for the home screen.

Design a custom rating widget in jetpack compose and canvas that displays filled, half, and empty stars for a 1–5 rating, using vector path data from SVG.

Implement a compose function that converts a decimal 1–5 rating into a map of field, half, and empty stars and renders them in a row with configurable spacing.

Implement a lazy column that displays two animated shimmer items during data loading and then renders the hero list when loading completes.

Implement initialize() in the remote mediator to use local cache when data is fresh and trigger a remote refresh after the cache timeout, based on last updated.

Modify the server test function to handle the new last updated field in the api response class, by using actual.last_updated for assertions to avoid time-mismatch errors.

Explain how the server caching header enables the HTTP client to automatically cache data for one year, and demonstrate how cached image URLs persist when the server is down.

Implement a search heroes use case, wire it through the repository and remote data source, and expose paging data of heroes to the search screen via the view model.

Demonstrates a details screen that uses a palette API to color the UI from hero images. Builds two custom components: info box and ordered list for a compose-based android app.

Create a reusable ordered list composable that displays a left-aligned title and numbered items, using a string list, a text color parameter, and material typography, with dark theme preview.

Design a bottom sheet content for the details screen in compose, showcasing the logo, hero name, info boxes, about text, and three lists with gesture-based expand and collapse.

Design a background content composable for the details screen that loads a hero image from a base URL with an error placeholder and a top-right close icon.

Animate the bottom sheet radius with a value tied to the current sheet fraction, applying 40 dp to the top corners when collapsed and 0 when expanded via rounded corners.

Explore the palette API to extract colors into a palette with six profiles. Use swatches, the builder, and color helpers such as body text color and title text color.

Create a palette generator object to convert image URLs to bitmaps and extract vibrant, dark vibrant, and body colors for text, using coil's image loader and the palette API.

Implement color palette extraction from hero images and apply vibrant colors to the details screen, including status bar updates, using a view model, shared flow events, and bitmap color extraction.

Create a fake burrito api to mock backend responses for testing the search heroes paging source, overriding search heroes logic with predefined heroes.

Test the search heroes paging source using a fake burrito API, validating single and multiple results, empty queries, and non existing heroes with JUnit and run blocking tests.

Create a second fake Boruto api for Android tests to support remote mediator testing, implementing get all heroes with paging logic and a calculate function for 1–5 pages.

Learn how to test a rating widget in Jetpack Compose by adding semantics, creating a compose test rule, and validating empty, half, and filled stars across multiple values.

Explore an alternative backend pagination approach by using a single heroes list and a limit parameter to generate pages with a windowed function, implemented via a hero repository alternative.

Discover how Heroku, a platform-as-a-service, runs apps in managed dynos (web, worker, one-off) and supports Git or GitHub deployment with addons and documentation.

Clean up the Android app and server, update dependencies, and resolve library conflicts. Refactor the splash screen, fix side effects, and simplify navigation and paging logic.

Update dependencies and clean up code in a modern Android app using Compose, Navigation, Room, and Coil 2.0; migrate deprecated code and replace remember image painter with AsyncImage.

Learn to migrate a Ktor server from 1.6 to 2.0, updating dependencies and imports. Adjust Gradle and tests using testApplication and body as text.

Migrate from the deprecated accompanist swipe refresh and system ui controller by implementing pull refresh with a refresh state, updating status bar color via activity window, and noting deprecated dependencies.

Migrate a Kotlin-based Ktor server to version 3, updating Gradle and Kotlin versions, and adopt new test patterns with the server test host, application blocks, and inject calls.