Spring Boot + kotlinx.html + HTMX Pattern Showcase

A showcase of common HTMX patterns built with Spring Boot, Kotlin, and kotlinx.html.

• No template engine — kotlinx.html generates all markup in pure Kotlin
• No JavaScript — HTMX handles interactivity through HTML attributes
• No database — an in-memory data store keeps things simple

Patterns Demonstrated

Active Search

Real-time search-as-you-type with hx-trigger delay and loading indicators.

Click to Edit

Inline editing with hx-get/hx-put and outerHTML swaps between view and edit modes.

Bulk Update

Select multiple contacts and toggle their status in batch using hx-include and targeted hx-target.

Infinite Scroll

Automatic pagination that loads more rows as you scroll, using hx-trigger="revealed".

Delete Row

Confirmation dialogs with hx-confirm and smooth CSS fade-out transitions on hx-delete.

Lazy Loading

Deferred content loading with hx-trigger="load" and spinners for expensive operations.

Each pattern page includes a "View source pattern" section showing the key HTMX attributes used.

Running

# Linux / macOS
./gradlew bootRun

# Windows
gradlew.bat bootRun

Then visit http://localhost:8080/ in your browser.

Tech Stack

• Spring Boot 3.5 with WebFlux
• Kotlin 2.0
• kotlinx.html 0.12 (type-safe HTML DSL)
• HTMX 2.0
• Pico CSS 2 (classless CSS framework)

License

See LICENSE.