Kotlin Formatter
Format Kotlin code online for free. Our Kotlin formatter applies consistent 4-space indentation, proper operator spacing, and clean structure following Kotlin coding conventions. Perfect for Android apps, Ktor backends, Kotlin Multiplatform, and Gradle KTS scripts.
Paste your Kotlin code or upload a .kt file to format it with consistent 4-space indentation, proper spacing, and clean structure following Kotlin coding conventions.
Why Use Our Kotlin Formatter?
Instant Formatting
Our tool to format Kotlin processes your content instantly in your browser. Format Kotlin files of any size with zero wait time — perfect for configuration files, project setups, and CI/CD pipelines.
Secure & Private Processing
Your data never leaves your browser when you use our Kotlin formatter online tool. Everything is processed locally using JavaScript, ensuring complete privacy and security for sensitive configuration data.
No File Size Limits
Format large Kotlin files without restrictions. Our free Kotlin Formatter handles any size input — from small configs to massive files with thousands of entries.
100% Free Forever
Use our Kotlin Formatter completely free with no limitations. No signup required, no hidden fees, no premium tiers, no ads — just unlimited, free formatting whenever you need it. The best free Kotlin formatter online available.
Common Use Cases for Kotlin Formatter
Android Development
Format Kotlin code for Android apps with proper indentation of activities, fragments, view models, and Jetpack Compose composables. Keep complex UI hierarchies readable and maintainable.
Backend with Ktor & Spring
Format Kotlin server-side code using Ktor, Spring Boot, or other frameworks. Keep route definitions, dependency injection, and service layers cleanly structured.
Kotlin Multiplatform
Format shared Kotlin Multiplatform code targeting Android, iOS, web, and desktop. Ensure consistent styling across expect/actual declarations and shared business logic.
Coroutines & Flow
Format complex Kotlin coroutine code with properly indented suspend functions, flow operators, channel operations, and structured concurrency patterns.
Gradle Build Scripts
Format Kotlin DSL Gradle build scripts (.kts files). Keep dependency declarations, plugin configurations, and custom tasks consistently structured.
Library Development
Format Kotlin libraries and SDKs before publishing. Ensure public APIs, extension functions, and DSL builders follow Kotlin coding conventions.
Understanding Kotlin Formatting
What is Kotlin Formatting?
Kotlin formatting is the process of restructuring Kotlin programming language files (.kt) with consistent indentation, proper spacing around operators, organized sections, and clean line breaks — while preserving all data and semantics.Kotlin is widely used for Android applications, backend services, multiplatform libraries, Gradle scripts, and any project using the Kotlin programming language. Our free Kotlin formatter online tool handles this instantly in your browser. Whether you need to format Kotlin for Android apps, server-side applications with Ktor and Spring Boot, Kotlin Multiplatform projects, Gradle build scripts, and data processing pipelines, our tool does it accurately and privately.
How Our Kotlin formatter Works
- Input Your Kotlin Content: Paste your Kotlin content directly into the text area or upload a
.ktfile from your device. Our Kotlin formatter online tool accepts any valid Kotlin input. - Instant Browser-Based Processing: Click the "Format Kotlin" button. Our tool processes your content entirely in your browser — no data is sent to any server, ensuring complete privacy.
- Download or Copy Formatted Output: View the cleanly formatted output with statistics. Copy the formatted content to your clipboard or download it as a file.
What Gets Formatted
- Consistent Spacing: Normalizes whitespace around operators like
=for a clean, uniform appearance throughout the file. - Section Organization: Ensures proper blank lines between sections and table headers for better visual separation and readability.
- Comment Preservation: All comments are preserved exactly as written. Formatting never removes or modifies your annotations and documentation.
- Trailing Whitespace Removal: Removes unnecessary trailing whitespace from all lines while maintaining blank lines for structure.
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Frequently Asked Questions - Kotlin formatter
A Kotlin formatter is a tool that restructures Kotlin files with consistent spacing, proper indentation, organized sections, and clean formatting — while preserving all data and semantics. Our Kotlin formatter online tool processes everything in your browser for maximum speed and privacy.
No. Our Kotlin formatter only changes the visual structure and whitespace in your Kotlin files. All keys, values, comments, tables, and data structures remain exactly the same. The formatted output is semantically identical to the original.
Absolutely! Your data is completely secure. All formatting happens directly in your browser using JavaScript — no data is ever uploaded to any server. Your configuration files, secrets, and sensitive data never leave your device.
Yes, our Kotlin formatter is 100% free with absolutely no hidden costs or limitations. There's no signup required, no premium tier, no usage limits, no file size restrictions, and no advertisements. Use it unlimited times for any project.
Yes! Our Kotlin formatter online tool handles files of any size. Since all processing happens in your browser, performance depends on your device, but modern browsers handle even very large Kotlin files efficiently.
Yes. Our formatter correctly handles Jetpack Compose composable functions with proper indentation of nested composable calls, modifier chains, remember blocks, and LaunchedEffect scopes. Deeply nested UI hierarchies are formatted for maximum readability.
Absolutely. Our Kotlin formatter preserves all comments — single-line (//), KDoc (/** */), and block comments (/* */). Annotations like @Composable, @Inject, @Serializable, and custom annotations are never removed or modified during formatting.
Yes! Our Kotlin formatter correctly handles DSL builders (like Ktor routing, Gradle scripts), extension functions, infix functions, operator overloading, scope functions (let, run, apply, also, with), and all other Kotlin language features.