LogTap

Realtime HTTP / WebSocket / Logger inspector for Android (OkHttp3) — with a built-in Ktor web server and a Material-style responsive web UI.
Inspect your app’s network calls and logs from any browser on the same network.

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🚀 Features

• Network

  • OkHttp3 Interceptor for HTTP(S)
  • WebSocket listener proxy
  • Pretty JSON viewer
  • Copy cURL command for easy reproduction

• Logger

  • Simple logger (LogTapLogger) with auto-tag by caller class
  • Supports levels: VERBOSE, DEBUG, INFO, WARN, ERROR, ASSERT
  • Optional Logcat bridge to stream system logcat

• UI

  • Runs on device via embedded Ktor server
  • Material-inspired, fully responsive (desktop, tablet, mobile)
  • Modes: Mix, Network only, Logger only
  • Filters: Method, HTTP status code / class, Log level, Full-text search
  • Live updates via WebSocket
  • Export JSON or HTML reports
  • Copy cURL or Summary directly from UI
  • Auto-scroll & toggle JSON pretty-print

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📸 Screenshots

Network View	Logger View	Detail Drawer	Sample app

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⚡ Usage

Installation

Add the dependency in your build.gradle:

debugImplementation 'com.github.Husseinhj.LogTap:logtap:v0.13.0'
releaseImplementation 'com.github.Husseinhj.LogTap:logtap-noop:v0.13.0'

💡 Always use the latest version from the GitHub Releases.

1. Initialize in your Application

class MyApp : Application() {
    override fun onCreate() {
        super.onCreate()
        if (BuildConfig.DEBUG) {
            LogTap.start(this) // Starts embedded server on port 8790
        }
    }
}

2. OkHttp with interceptor

val client = OkHttpClient.Builder()
    .addInterceptor(LogTapInterceptor())
    .build()

3. Logger

LogTapLogger.d("Something happened")
LogTapLogger.e("Network error", throwable)

4. View in browser

Open in your desktop browser:

http://<device-ip>:8790/

Tip – Watch Logcat for the server URL

When the embedded server is ready, LogTap writes the exact address to Logcat so you can copy/paste it easily. Look for a line like:

...logtapsample  I  LogTap server ready at http://192.168.178.66:8790/

(If you don't see the IP, ensure your app has ACCESS_NETWORK_STATE or LogTap will fall back to best-effort interface detection.)

Multiple apps at once (auto‑port increment)

If you run LogTap from multiple apps on the same device at the same time, LogTap will automatically try the next port when the base port is busy. By default it starts at 8790; if that’s taken, it tries 8791, 8792, and so on until it finds a free port (a small, bounded range).

You’ll see the chosen address printed to Logcat when the server is ready, for example:

… I LogTap server ready at http://192.168.178.66:8790/
… I LogTap server ready at http://192.168.178.66:8791/

Tip: You can also pick different base ports per app to avoid clashes entirely.

Example

App A – use default base port (8790):

class AppA : Application() {
  override fun onCreate() {
    super.onCreate()
    LogTap.start(this) // tries 8790, then 8791, ... if needed
  }
}

App B – set an explicit base port (e.g., 8795):

class AppB : Application() {
  override fun onCreate() {
    super.onCreate()
    LogTap.start(
      this,
      LogTap.Config(
        port = 8795,        // base port; LogTap will auto‑increment if 8795 is in use
        capacity = 5000
      )
    )
  }
}

Then open in your browser from the same network:

http://<device-ip>:8790/   // App A
http://<device-ip>:8791/   // App A (if 8790 was busy)
http://<device-ip>:8795/   // App B
http://<device-ip>:8796/   // App B (if 8795 was busy)

5. Advanced: Automatic Logcat collection

For more settings and to automatically collect logs from Android's logger, you can use LogTapLogcatBridge together with a LogTapSinkAdapter:

class LogTapApp : Application() {
  private val logSink = LogTapSinkAdapter()

  override fun onCreate() {
    super.onCreate()

    LogTapLogcatBridge.start(logSink)
    LogTapLogger.d("LogTapLogcatBridge started")
    LogTap.start(this, LogTap.Config(port = 8790, capacity = 5000))

    LogTapLogger.setDebug(BuildConfig.DEBUG)
    LogTapLogger.setAllowReleaseLogging(false)
    LogTapLogger.setMinLevel(
      if (BuildConfig.DEBUG)
        LogTapLogger.Level.DEBUG
      else
        LogTapLogger.Level.WARN
    )
  }
}

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Per-flavor installation

You can restrict LogTap only to a specific build flavor (e.g., dev) by declaring dependencies under the corresponding configuration. For example:

dependencies {
    devDebugImplementation 'com.github.Husseinhj.LogTap:logtap:v0.13.0'
    devReleaseImplementation 'com.github.Husseinhj.LogTap:logtap-noop:v0.13.0'
}

Note: Other flavors (like staging or production) will not include LogTap unless you declare the dependency for them as well.

Per-flavor Kotlin code (safe stubs to avoid release deps)

Sometimes you want no LogTap library at all in release builds (not even the -noop artifact), but still keep your source code compiling. The simplest and safest way is to wrap LogTap behind your own tiny facade and provide a no-op implementation in release sources.

1) Declare flavors (example)

android {
  flavorDimensions += "env"
  productFlavors {
    create("dev") { dimension = "env" }
    create("staging") { dimension = "env" }
    create("production") { dimension = "env" }
  }
}

2) Depend only where you need it

• If you want the library only in the dev flavor, keep:

devDebugImplementation 'com.github.Husseinhj.LogTap:logtap:v0.13.0'
// (Optional) If you also build devRelease, use the noop artifact there:
devReleaseImplementation 'com.github.Husseinhj.LogTap:logtap-noop:v0.13.0'

• If you prefer no dependency at all on release variants (including prod/staging), do not add a release dependency. We’ll provide stubs instead.

3) Create a small facade that your app calls

Use a single API from your app and hide LogTap behind it.

// src/main/java/com/example/logtap/LogTapFacade.kt
package com.example.logtap

import android.app.Application

object LogTapFacade {
  fun start(app: Application) {}
  fun d(message: String) {}
  fun e(message: String, t: Throwable? = null) {}
}

4) Provide real implementation only in the flavor that needs it

// src/dev/java/com/example/logtap/LogTapFacade.kt
package com.example.logtap

import android.app.Application
import com.github.husseinhj.logtap.LogTap
import com.github.husseinhj.logtap.logger.LogTapLogger

object LogTapFacade {
  fun start(app: Application) {
    LogTap.start(app)
    LogTapLogger.d("LogTap started")
  }
  fun d(message: String) = LogTapLogger.d(message)
  fun e(message: String, t: Throwable?) = LogTapLogger.e(message, t)
}

5) Provide a no-op implementation for release (and/or staging, production)

// src/release/java/com/example/logtap/LogTapFacade.kt
package com.example.logtap

import android.app.Application

object LogTapFacade {
  fun start(app: Application) { /* no-op */ }
  fun d(message: String) { /* no-op */ }
  fun e(message: String, t: Throwable? = null) { /* no-op */ }
}

With this setup:

• Your app code always calls LogTapFacade (never the library directly).
• Dev variants get the real implementation and the actual dependency.
• Release/Production variants compile against the no-op class and ship with zero LogTap code.

6) Use in Application

class MyApp : Application() {
  override fun onCreate() {
    super.onCreate()
    // Facade is flavor-aware; in release this is a no-op
    LogTapFacade.start(this)
  }
}

7) Optional: variant-aware source sets

You can create stubs per-flavor too, e.g. src/production/java/... and src/staging/java/... if those should also be no-op.

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🔐 Security

• LogTap is meant for debug builds only.
• Don’t enable it in production.
• Use the provided -noop artifact in release builds.
• You can also guard calls with if (BuildConfig.DEBUG).

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🛠 Development

• UI is embedded in Resources.kt (HTML, CSS, JS).
• Served from:
  • / → Main web UI
  • /api/logs → JSON API
  • /ws → WebSocket stream
• Contributions welcome! Please open an issue or PR.

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📜 License

MIT License – see LICENSE for details.