Prebid Integration Modes

The Sellwild SDK supports three distinct Prebid integration modes. Each mode represents a different trade-off between implementation complexity, latency, and native rendering capability. Publishers can start with Mode A and progressively migrate to Mode B or Mode C as requirements evolve.

Mode A: Prebid.js in WebView (Default)

Mode A runs the standard Prebid.js auction inside a WebView that is embedded within the native ad container. This is the default integration mode and requires no server-side infrastructure.

How it works:

1. The SDK creates a lightweight WebView within the ad placement.
2. Prebid.js runs inside the WebView, executing the client-side header bidding auction.
3. Winning creative HTML is rendered directly in the WebView.
4. The native shell handles viewport sizing, visibility tracking, and lifecycle events.

Advantages:

• Zero server infrastructure required.
• Full Prebid.js adapter ecosystem available out of the box.
• Fastest path to integration for publishers already using Prebid.js on web.

Limitations:

• Auction latency is borne by the end user's device.
• WebView rendering can introduce minor visual inconsistencies compared to fully native UI.
• Each ad instance carries the memory overhead of a WebView.

Mode B: Prebid Server S2S

Mode B moves the header bidding auction to a server-side Prebid Server instance. This is the integration mode currently being proposed for partners such as Weatherbug, where latency and device resource consumption are primary concerns.

How it works:

1. The SDK sends an OpenRTB bid request to the Sellwild Prebid Server endpoint at https://prebid.sellwild.com.
2. Prebid Server executes the auction server-side, calling all configured demand partners in parallel.
3. The server returns the winning bid and creative payload to the SDK.
4. The SDK renders the creative in a WebView or, where possible, maps structured native assets to native UI components.

Advantages:

• Auction latency is offloaded to the server, reducing time-to-render on device.
• Lower CPU and memory footprint because Prebid.js does not run on the client.
• Centralized demand partner configuration -- changes take effect without an SDK update.
• Better suited for resource-constrained devices and high-frequency ad refresh scenarios.

Limitations:

• Requires a running Prebid Server instance (Sellwild hosts this at prebid.sellwild.com).
• Demand partner support is limited to adapters available in Prebid Server (Go or Java).
• Slightly more complex initial setup compared to Mode A.

Configuration:

SellwildSDK.configure({
  publisherId: 'your-publisher-id',
  prebidMode: 'server',
  prebidServerUrl: 'https://prebid.sellwild.com',
});

Mode C: Prebid Mobile SDK (Future)

Mode C integrates the Prebid Mobile SDK directly into the native layer. This mode is on the roadmap for a future release and targets publishers who need fully native ad rendering without any WebView dependency.

How it works:

1. The Prebid Mobile SDK is embedded as a native dependency alongside the Sellwild SDK.
2. Bid requests are sent via the Prebid Mobile SDK's built-in networking layer, either directly to demand partners or through Prebid Server.
3. Native demand responses are mapped to platform-native UI components (UIKit/SwiftUI on iOS, Jetpack Compose/Views on Android).
4. No WebView is used at any stage of the rendering pipeline.

Advantages:

• Fully native rendering for the best possible user experience and performance.
• Deep integration with platform accessibility and layout systems.
• No WebView overhead whatsoever.

Limitations:

• Significantly more implementation effort on each platform.
• Requires the Prebid Mobile SDK as an additional native dependency, increasing binary size.
• Not yet available -- currently in the design phase.

Comparison Table

	Mode A: Prebid.js WebView	Mode B: Prebid Server S2S	Mode C: Prebid Mobile SDK
Auction location	Client (WebView)	Server (prebid.sellwild.com)	Client (native)
Rendering	WebView	WebView or hybrid native	Fully native
Latency	Higher (client-side auction)	Lower (server-side auction)	Lowest (no WebView)
Device resource usage	Moderate (WebView + JS engine)	Low (network call only)	Low (native only)
Adapter ecosystem	Full Prebid.js adapters	Prebid Server adapters	Prebid Mobile adapters
Infrastructure required	None	Prebid Server instance	None
Configuration changes	Requires SDK update	Server-side, no SDK update	Requires SDK update
Status	Available (default)	Available	Planned

When to Use Which Mode

Choose Mode A when you need the fastest integration path, already have Prebid.js configurations, or want to maximize demand partner reach through the full Prebid.js adapter library.

Choose Mode B when latency is a priority, you want centralized demand configuration, or you are running ads on devices where WebView auction overhead is a concern. Mode B is the recommended mode for production deployments that require predictable ad load times.

Choose Mode C (once available) when your app demands fully native ad rendering with zero WebView usage, or when platform-specific accessibility and layout integration is a hard requirement.

Migration Path: A to B to C

The SDK is designed so that switching modes requires only a configuration change, not a re-integration.

A to B

1. Ensure your Prebid Server account is provisioned. Contact the Sellwild team to confirm your demand partner configuration is mirrored on prebid.sellwild.com.
2. Update the SDK configuration to set prebidMode to 'server' and provide the prebidServerUrl.
3. Test in a staging environment. Validate that fill rates and latency meet expectations.
4. Roll out to production. No changes to ad placement code are required.

// Before (Mode A -- default)
SellwildSDK.configure({
  publisherId: 'your-publisher-id',
});

// After (Mode B)
SellwildSDK.configure({
  publisherId: 'your-publisher-id',
  prebidMode: 'server',
  prebidServerUrl: 'https://prebid.sellwild.com',
});

B to C

1. Update the Sellwild SDK to the version that includes Mode C support (release TBD).
2. Add the Prebid Mobile SDK as a native dependency on each platform.
3. Update the SDK configuration to set prebidMode to 'native'.
4. Replace any custom WebView-based ad view styling with native layout configuration.

// Mode C (future)
SellwildSDK.configure({
  publisherId: 'your-publisher-id',
  prebidMode: 'native',
});

Each migration step is backward-compatible. If issues arise after switching modes, reverting to the previous mode is a single configuration change.