Yes2SDK for YouTube Playables - Platform Guide

Prerequisite

Install Yes2SDK first. None of the API below compiles until the SDK is installed in your project:

Unity: UPM git URL https://github.com/yes2games/yes2sdk-unity.git#<version>, then Yes2SDK > Build Window > Install Template.
Defold: add the release archive to game.project [project] dependencies, then Project > Fetch Libraries.

If you use the Yes2SDK MCP, call get_install_instructions for exact pinned steps and detect_sdk to confirm the SDK is installed before generating any code.

Requirements

YouTube Playables runs your game inside a sandboxed iframe on youtube.com and applies the strictest certification checks of any Yes2Games platform. Several APIs are certification-mandatory: without them YouTube will reject the game even if it runs fine in the Inspector.

API Requirements

The Yes2SDK methods below cover every YouTube Playables (ytgame) call you need. The middle column is what Yes2SDK invokes on window.ytgame under the hood. You never call those directly. The same Yes2SDK API works in TypeScript, Unity (Yes2SDK.*), and Defold (yes2sdk.*). Only the method-naming convention changes (see Integration Example below).

Platform Requirement	Yes2SDK API	Required
`ytgame.game.firstFrameReady()`	`Yes2SDK.initializeAsync()` (fires after first paint)	Required (cert)
`ytgame.game.gameReady()`	`Yes2SDK.startGameAsync()`	Required (cert): game is interactable
`ytgame.system.onPause(fn)`	`Yes2SDK.on('pause', fn)`	Required (cert): game MUST stop on pause
`ytgame.system.onResume(fn)`	`Yes2SDK.on('resume', fn)`	Required (cert)
`ytgame.system.onAudioEnabledChange(fn)`	`Yes2SDK.on('audioEnabledChange', fn)`	Required (cert): match platform mute state
`ytgame.system.isAudioEnabled()`	`session.isAudioEnabled()`	Required (cert): read at startup
`ytgame.system.getLanguage()`	`session.getLocale()` (BCP-47, cached on init)	Recommended
`ytgame.ads.requestInterstitialAd()`	`ads.showInterstitial(placement, cbs)`	Recommended (monetization)
`ytgame.ads.requestRewardedAd(rewardId)`	`ads.showRewarded(placement, cbs)`	Recommended (monetization)
`ytgame.game.loadData()` + `saveData(json)`	`data.getInt/setInt`, `data.getString/setString`, ...	Optional (cloud, 3 MiB cap)
`ytgame.engagement.sendScore({ value })`	`score.addScore(n)`	Optional (shown in YouTube UI)
`ytgame.health.logError/logWarning`	Auto-wired from SDK logger	Optional

Banner ads, auth, friends, and IAP are not supported on YouTube Playables. ads.showBanner, auth.*, banners.*, friends.*, and iap.* return FeatureNotSupported.

Critical Rules

Rule	Description
`firstFrameReady` after first paint	Yes2SDK waits one `requestAnimationFrame` after init so your splash/loading screen is on screen before signalling. Do not block the first paint with synchronous work.
`gameReady` only when interactable	Call `startGameAsync()` once all assets are loaded and the player can actually input. Calling it during loading = cert fail.
Pause/resume are mandatory	Pause callback must stop the game loop, audio, and network. Resume is not guaranteed. Never assume it will fire.
Honor `audioEnabledChange`	When YouTube mutes via its player UI, your game must mute too. Read `isAudioEnabled()` at startup, then subscribe to changes.
No external scripts	YouTube's sandbox blocks external `<script src="http...">`. All code must be inlined or bundled (the Yes2Games Dashboard handles bundling).
`loadData()` before `saveData()`	The Data module preloads on init. Don't call `data.set*()` before `initializeAsync()` resolves.

Integration Example

TypeScript / JavaScript

await Yes2SDK.initializeAsync();   // -> ytgame.game.firstFrameReady()

// Cert requirement #1 — honor platform pause
Yes2SDK.on('pause',  () => pauseGameLoop());
Yes2SDK.on('resume', () => resumeGameLoop());

// Cert requirement #2 — match the platform audio state
Yes2SDK.on('audioEnabledChange', ({ enabled }) => {
    setAudioMuted(!enabled);
});
setAudioMuted(!Yes2SDK.session.isAudioEnabled());

await Yes2SDK.startGameAsync();    // -> ytgame.game.gameReady()
Yes2SDK.game.gameplayStart();

// Submit score to YouTube UI
Yes2SDK.score.addScore(1500);

// Rewarded ad
Yes2SDK.game.gameplayStop();
await Yes2SDK.ads.showRewarded('extra-life', {
    beforeAd:  () => pauseGameLoop(),
    afterAd:   () => { resumeGameLoop(); Yes2SDK.game.gameplayStart(); },
    adViewed:  () => grantExtraLife(),
    adDismissed: () => {/* no reward */},
});

Unity C#

Yes2SDK.Yes2SDK.OnPause  += () => { AudioListener.pause = true;  Time.timeScale = 0f; };
Yes2SDK.Yes2SDK.OnResume += () => { AudioListener.pause = false; Time.timeScale = 1f; };
Yes2SDK.Yes2SDK.OnAudioEnabledChange += (enabled) => {
    AudioListener.volume = enabled ? 1f : 0f;
};

Yes2SDK.Yes2SDK.InitializeAsync(onSuccess: () =>
{
    Yes2SDK.Yes2SDK.StartGameAsync(onSuccess: () =>
    {
        Yes2SDK.Yes2SDK.Game.GameplayStart();
    });
});

void OnLevelCompleted(int score)
{
    Yes2SDK.Yes2SDK.Score.AddScore(score);
}

Defold Lua

yes2sdk.initialize(function(self, success, error)
    if not success then return end

    -- Cert: honor pause/resume
    yes2sdk.on_pause(function(self) pause_game_loop() end)
    yes2sdk.on_resume(function(self) resume_game_loop() end)

    -- Cert: honor audio mute state
    yes2sdk.on_audio_enabled_change(function(self, enabled)
        sound.set_group_gain("master", enabled and 1 or 0)
    end)
    if not yes2sdk.session_is_audio_enabled() then
        sound.set_group_gain("master", 0)
    end

    yes2sdk.start_game(function(self, success, error)
        yes2sdk.session_gameplay_start()
    end)
end)

-- Submit score
yes2sdk.score_add(level_score)

How YouTube Playables Works Under the Hood

The ytgame global is loaded from https://www.youtube.com/game_api/v1 and only works inside the YouTube iframe. Outside YouTube, the SDK loader treats this as a no-op and the platform reports as Unknown / Debug.
Yes2SDK.initializeAsync() waits one requestAnimationFrame before calling firstFrameReady() so your loading screen is guaranteed to be visible: required by Playables certification.
Yes2SDK.startGameAsync() calls gameReady() to dismiss YouTube's loading shim. Do not call this until your game is actually playable.
data.* is backed by ytgame.game.loadData() / saveData() with a single JSON blob (3 MiB cap). Writes are batched with a 500 ms debounce.
score.addScore(n) calls ytgame.engagement.sendScore({ value: n }). YouTube displays the highest score, not the latest. Submit every score.
Errors and warnings from the SDK are mirrored to ytgame.health.logError/logWarning for YouTube's health reporting.

How to Submit

You don't upload to YouTube yourself. The Yes2Games team handles platform submission via YouTube Creator Studio's Playables flow.

Upload a build on your game page (Onboarding → Stage 1)
Test it in the Inspector (Onboarding → Stage 3). Pay extra attention to the pause/resume and audio-mute checks since YouTube's cert is the strictest
Click Request Publish in Onboarding → Stage 4 and select YouTube Playables
The Yes2Games team runs YouTube's cert checklist against the build, submits it through YouTube Creator Studio, and shepherds it through Google's review
You'll see status updates and feedback messages on the game page

If YouTube cert sends back changes, upload a new build and request publish again on that build.

What Yes2Games reviewers (and YouTube's cert) check before submission

firstFrameReady fires within the loading screen window
gameReady fires only when the game is interactable
Game pauses immediately on onPause (audio + game loop + network)
Game audio matches isAudioEnabled() at startup and on every change
No external scripts loaded at runtime
Game does not assume onResume will fire after onPause
Cloud saves stay under 3 MiB serialized

Common Rejection Reasons

Issue	Fix
`firstFrameReady` fires before first paint	The SDK already handles this. Don't block init with sync asset loading. Move heavy work behind `setLoadingProgress` updates.
Game keeps playing audio after `onPause`	Subscribe to `Yes2SDK.on('pause', ...)` and `on('audioEnabledChange', ...)`. Don't rely on `visibilitychange`.
Audio doesn't mute when player mutes YouTube	Read `session.isAudioEnabled()` at startup AND subscribe to `audioEnabledChange`.
`gameReady` called too early	Wait until all assets are loaded and the game accepts input. Loading screens don't count as "ready".
Save data > 3 MiB	Trim what you store. YouTube hard-caps cloud saves at 3 MiB UTF-16.
External script blocked by CSP	Bundle all third-party code into your game zip via the Yes2SDK Dashboard. Don't load `<script src="https://...">` at runtime.

Platform-Specific Notes

Banners / Auth / Friends / IAP: Not supported. isSupported() returns false; calls reject with FeatureNotSupported.
Locale: session.getLocale() returns the cached BCP-47 tag (en, fr-FR, ja, ...). Cached at init so calls are synchronous.
Score: YouTube shows the highest score automatically. No leaderboard API needed. Submit every score with score.addScore(n).
Sandbox: No DOM access beyond the game canvas, no third-party network requests, no localStorage quota beyond what data.* uses internally.
Outside YouTube: When run outside the YouTube iframe (Inspector, dev preview), the SDK no-ops on platform calls and reports the platform as Debug / Unknown.

Build & Upload Limits

Total size: 250 MiB
Initial download: 30 MiB (SHOULD be <15 MiB)
File count: 8000 files
Max per-file: 30 MiB (SHOULD be <512 KiB per file)
Entry point: index.html
Paths: relative paths only; filenames limited to [A-Za-z0-9_-.]
External requests: forbidden, no off-platform network
Compression: not documented by Google
Persistence: SDK saveData only; <3 MiB total, ~64 KiB practical per-save cap
Canvas: all aspect ratios, lock nothing; peak JS heap <512 MB
Review: early-access, application-gated; SDK must load before game code; firstFrameReady() then gameReady()

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