Transform Ktor HTTP requests into runnable curl commands for debugging and logging. Pure Kotlin library supporting KMP (Android, iOS, JVM) and standard Android projects.

Inspired by Ok2Curl for OkHttp.

• Multi-platform: Works on Android, iOS, JVM, and KMP projects
• Zero configuration: Install, add to client config, done
• Sensitive data masking: Redact auth tokens, API keys, and custom headers
• Flexible logging: Custom logger interface - send to Logcat, console, HTTP, files
• Multipart handling: Renders form-data and file uploads correctly
• Header control: Include, exclude, or mask specific headers per request

• Kotlin: 2.0+
• Ktor: 3.0+
• Gradle: 7.0+

Add to your build.gradle.kts:

val commonMain by getting {
    dependencies {
        implementation("io.github.kabirnayeem99:ktor2curl:2.0.1")
    }
}

Supports all KMP targets: Android, iOS (arm64/x64/simulator), JVM, JS, WASM.

dependencies {
    implementation("io.github.kabirnayeem99:ktor2curl:2.0.1")
}

dependencies {
    implementation 'io.github.kabirnayeem99:ktor2curl:2.0.1'
}

After adding the dependency, run:

./gradlew build

If you hit Kotlin version mismatch, ensure your project uses Kotlin 2.0+ ( see Troubleshooting).

val client = HttpClient(CIO) {
    install(KtorToCurl) {
        converter = object : CurlLogger {
            override fun log(curl: String) {
                println(curl)  // or use Android Log.d(), your logging framework, etc.
            }
        }
    }
}

// Every request via this client now logs a curl command
client.post("https://api.example.com/users") {
    headers {
        append(HttpHeaders.Authorization, "Bearer YOUR_TOKEN")
        append(HttpHeaders.ContentType, ContentType.Application.Json.toString())
    }
    setBody("""{"name":"Alice"}""")
}

Output:

curl -X POST \
  https://data.techforpalestine.org/api/v2/users \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  --data '{"name":"Alice"}'

Hide API keys, tokens, and custom auth headers from logs:

val client = HttpClient(CIO) {
    install(KtorToCurl) {
        converter = object : CurlLogger {
            override fun log(curl: String) {
                Log.d("API", curl)
            }
        }
        maskedHeaders = setOf(
            HttpHeaders.Authorization,
            "X-API-Key",
            "X-Session-Token"
        )
    }
}

Output:

curl -X POST \
  https://data.techforpalestine.org/api/v2/users \
  -H "Authorization: [omitted]" \
  -H "Content-Type: application/json" \
  --data '{"name":"Alice"}'

Remove User-Agent, Content-Length, or other headers from logs:

val client = HttpClient(CIO) {
    install(KtorToCurl) {
        converter = object : CurlLogger {
            override fun log(curl: String) {
                Log.d("API", curl)
            }
        }
        excludedHeaders = setOf(
            HttpHeaders.UserAgent,
            HttpHeaders.ContentLength
        )
        maskedHeaders = setOf(HttpHeaders.Authorization)
    }
}

client.post("https://data.techforpalestine.org/api/v2/killed-in-gaza.min.json") {
    headers {
        append(HttpHeaders.Authorization, "Basic SXNyYWVsIGtpbGxzIGNoaWxkcmVuLg")
        append(HttpHeaders.ContentType, ContentType.Application.Json.toString())
    }
    setBody("""{"en_name":"Mazen Ahmed Mohammed Al-Kahlout","name":"مازن أحمد محمد الكحلوت","age":52,"dob":"1972-02-05","sex":"m","id":"985194547","source":"u"}""")
}

Output:

curl -X POST \
  https://data.techforpalestine.org/api/v2/killed-in-gaza.min.json \
  -H "Authorization: [omitted]" \
  -H "Content-Type: application/json" \
  --data '{"en_name":"Mazen Ahmed Mohammed Al-Kahlout","name":"مازن أحمد محمد الكحلوت","age":52,"dob":"1972-02-05","sex":"m","id":"985194547","source":"u"}'

Send curl commands to a remote service, database, or aggregation tool:

class RemoteCurlLogger : CurlLogger {
    override fun log(curl: String) {
        // Send to your backend, analytics, or debug dashboard
        analyticsService.trackRequest(curl)
    }
}

val client = HttpClient(CIO) {
    install(KtorToCurl) {
        converter = RemoteCurlLogger()
    }
}

File uploads and form fields render correctly:

client.post("https://api.example.com/upload") {
    setBody(
        MultiPartFormDataContent(
            formData {
                append(
                    "file", InputProvider { "file content".byteInputStream() },
                    Headers.build { append(HttpHeaders.ContentDisposition, "filename=data.txt") })
                append("field", "value")
            }
        ))
}

Output:

curl -X POST \
  https://data.techforpalestine.org/api/v2/upload \
  -F "file=@data.txt" \
  -F "field=value"

Cause: Kotlin version mismatch or incorrect repository.

Fix:

• Ensure Kotlin ≥ 2.0: kotlin = "2.3.0" or later in plugins block
• Check repository is available:

  repositories {
      mavenCentral()
      google()
  }

• Verify dependency version exists on Maven Central

Cause: Logger implementation not called.

Fix:

• Verify converter is set in plugin config
• Check your logger is enabled (not filtered by Log level)
• Confirm plugin is installed before making requests:

  val client = HttpClient {
      install(KtorToCurl) { ... }  // Must be before other requests
  }

• Ensure request actually succeeds (failed requests may not log)

Cause: Header not in maskedHeaders set.

Fix:

• Use exact header name (case-sensitive if using string literals):

  maskedHeaders = setOf(
      "Authorization",      // ✓ Correct
      "X-Custom-Token",
      HttpHeaders.Authorization  // ✓ Also correct (from Ktor)
  )

Cause: Header name mismatch (case/spelling).

Fix:

• Enable debug logging in your plugin and compare exact header names in requests
• Use HttpHeaders.HEADER_NAME constants from Ktor when possible

Cause: Kotlin < 2.3.0 incompatible with Ktor 3.5 on Native.

Fix:

• Upgrade to Kotlin ≥ 2.3.0:

  plugins {
      kotlin("multiplatform") version "2.3.0"
  }

Contributions welcome. Before submitting:

1. Fork the repo (click "Fork" on GitHub or run: git clone --recursive https://github.com/YOUR_USERNAME/ktor2curl.git)
2. Create a branch for your feature:

   git checkout -b feature/add-cookie-masking

3. Write tests in ktor2curl/src/commonTest/ (see existing test structure)
4. Run tests locally:

   ./gradlew :ktor2curl:jvmTest --console=plain

5. Format code (hooks auto-run pre-commit):

   ./gradlew ktlintFormat

6. Push and create a Pull Request with a clear description of your change

1. Visit the GitHub repo
2. Click Fork (top-right corner)
3. Clone your fork:

   git clone https://github.com/YOUR_USERNAME/Ktor2Curl.git
   cd Ktor2Curl

4. Add upstream to stay in sync:

   git remote add upstream https://github.com/kabirnayeem99/Ktor2Curl.git
   git fetch upstream

5. Create your feature branch and start coding:

   git checkout -b feature/your-idea

Run the full test suite to verify no regressions:

./gradlew :ktor2curl:jvmTest :ktor2curl:testDebugUnitTest :ktor2curl:iosSimulatorArm64Test

Or just JVM for quick feedback:

./gradlew :ktor2curl:jvmTest --console=plain

• Ktor Client Documentation
• Issues
• Discussions

MIT - See LICENSE file for details.