How to Add Custom SponsorBlock Categories in SmartTube

You can add custom SponsorBlock categories in SmartTube either through the in-app settings menu (which stores them in SharedPreferences under sb_custom_categories) or by modifying the source code to declare new constants in SponsorBlockCategory.kt and string resources in strings.xml.

SmartTube, the advanced Android TV client for YouTube maintained by yuliskov/SmartTube, integrates the SponsorBlock service to skip unwanted video segments. While the app ships with standard categories like sponsor, intro, and outro, the codebase supports extending these with user-defined categories that map to specific SponsorBlock API keys.

Understanding the Category Architecture

Before adding categories, you need to understand how SmartTube structures this data across three layers: the user-facing strings, the internal API constants, and the persistence mechanism.

String Resources for Display Names

The human-readable labels that appear in the settings menu are defined in the common module's string resources. In common/src/main/res/values/strings.xml, you will find entries for built-in categories:

<string name="content_block_sponsor">Sponsor</string>
<string name="content_block_intro">Intro</string>
<string name="content_block_outro">Outro</string>

When adding a custom category through the UI, the display name you enter is saved alongside the technical configuration.

Category Constants in SponsorBlockCategory.kt

The internal mapping between user selections and SponsorBlock API requests lives in smarttubetv/src/main/java/com/smarttube/sponsorblock/SponsorBlockCategory.kt. This file contains constants representing the official SponsorBlock segment types:

object SponsorBlockCategory {
    const val SPONSOR = "sponsor"
    const val INTRO = "intro"
    const val OUTRO = "outro"
    const val INTERACTION = "interaction"
    // ... additional built-in categories
}

When the app constructs a request to the SponsorBlock server, it uses these string constants as category parameters.

Persistence via SponsorBlockPreferences.kt

Custom categories created at runtime are serialized and stored by SponsorBlockPreferences.kt. The class manages a SharedPreferences entry under the key sb_custom_categories, storing a JSON array of objects containing the display name, API key, and optional color code.

Adding Categories Through the User Interface

The simplest method requires no source code modification and works on any installed release.

1. Navigate to Settings → SponsorBlock → Manage Categories.
2. Select "Add Custom Category".
3. Enter the Display Name (e.g., Product Placement).
4. Enter the API Key exactly as recognized by SponsorBlock (e.g., product_placement or selfpromo).
5. Optionally, select a Color for the segment indicator.
6. Tap Save.

The SponsorBlockPreferences class immediately writes this entry to SharedPreferences under sb_custom_categories. The app merges this custom list with the built-in categories defined in SponsorBlockCategory.kt on the next video load.

Adding Categories via Source Code Modification

If you are building SmartTube from source and want to permanently bundle new categories into the APK, modify the following files before compilation.

Step 1: Add String Resources

Add your category's display name to common/src/main/res/values/strings.xml:

<string name="content_block_product_placement">Product Placement</string>
<string name="content_block_custom_segment">Custom Segment</string>

Step 2: Declare the Category Constant

Open smarttubetv/src/main/java/com/smarttube/sponsorblock/SponsorBlockCategory.kt and add your new constant:

object SponsorBlockCategory {
    // Existing categories
    const val SPONSOR = "sponsor"
    const val INTRO = "intro"
    
    // Your custom addition
    const val PRODUCT_PLACEMENT = "product_placement"
    const val CUSTOM_SEGMENT = "custom"
}

Step 3: Update the Settings UI

Modify SponsorBlockSettingsFragment.kt (or the equivalent settings presenter) to include your new category in the default array presented to users. This ensures the checkbox appears in the category management screen without requiring manual entry.

Step 4: Rebuild and Deploy

Compile the project using the standard Gradle build process. Your new category will now appear as a toggleable option alongside the official SponsorBlock categories.

Summary

• String resources in common/src/main/res/values/strings.xml control what users see in menus.
• API constants in SponsorBlockCategory.kt define the keys sent to SponsorBlock servers.
• Runtime custom categories are stored in SharedPreferences via SponsorBlockPreferences.kt using the key sb_custom_categories.
• UI workflow: Settings → SponsorBlock → Manage Categories → Add Custom Category.
• Code workflow: Add strings, add constants, update UI fragments, rebuild APK.

Frequently Asked Questions

How are custom SponsorBlock categories stored in SmartTube?

Custom categories are serialized as JSON and stored in Android SharedPreferences under the key sb_custom_categories, managed by the SponsorBlockPreferences class. This allows the app to persist your custom entries between sessions without modifying the source code.

Can I use custom SponsorBlock categories without compiling the SmartTube APK?

Yes. Use the in-app settings menu at Settings → SponsorBlock → Manage Categories → Add Custom Category. This writes directly to the app's private preferences and requires no technical expertise or source code access.

What is the difference between the Display Name and API Key when adding a category?

The Display Name is the user-facing label shown in SmartTube's settings and on-screen segment indicators. The API Key is the exact string identifier that SponsorBlock's database uses to classify segments (e.g., sponsor, selfpromo, music_offtopic). The API key must match SponsorBlock's expected values to retrieve segments correctly.

Do custom SponsorBlock categories sync across my devices?

No. Because custom categories added via the UI are stored locally in SharedPreferences (sb_custom_categories), they do not sync through any cloud service. You must manually recreate them on each device, or build a custom APK with hardcoded categories if you want consistency across multiple installations.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}