PrebidNativeCache stores Native adm without the mandatory "native" wrapper (OpenRTB Native 1.2 / ORTB 2.5 Compliance Issue)

[AndrewHoang1995]

Describe the bug
PrebidNativeCache is returning/storing a Native adm without the required "native" wrapper, which violates the OpenRTB Native 1.2 / ORTB 2.5 specification.

The OpenRTB spec states that bid.adm must contain a JSON string whose root object is "native".

To Reproduce
Incorrect (current behavior):

{
"adm": "{"ver":"1.2","assets":[...],"link":{...}}"
}

Expected behavior
Correct according to the ORTB Native specification:
{
"adm": "{"native": {"ver":"1.2","assets":[...],"link":{...}}}"
}
The missing "native" wrapper causes:

Native renderers to fail parsing

Prebid Mobile SDK incompatibility

Missing assets

Crashes due to invalid ORTB Native format

InMobi Return adm ORTB 2.5 : "

adm.txt

"

Screenshots

Smartphone (please complete the following information):

Device: Pixel 8

OS: Android 16

SDK: Prebid Mobile Android 3.0.2

Additional context
Many Native Ad renderers (especially on Android / iOS) parse the adm based exactly on the ORTB Native specification.
The extra "native" wrapper causes:

JSON parsing errors

Missing or unreadable assets

Crashes when expected fields aren’t found

Additional custom code required to unwrap the response

Suggested Fix:
When storing native responses in cache, store the NativeResponse object directly, without wrapping it inside "native".

Report by :
AndrewHoang

[YuriyVelichkoPI]

Hi @AndrewHoang1995.

Prebid SDK implements OpenRTB Dynamic Native Ads API Specification Version 1.2
https://iabtechlab.com/wp-content/uploads/2016/07/OpenRTB-Native-Ads-Specification-Final-1.2.pdf

Which clearly states (section 5.1 Native Markup Response Object) that the top-level "native" object is not required:

The code you shared also doesn't intentionally ignore the top-level object in the bid response - it is not supported according to the standard.

However, it doesn't mean that Prebid SDK can't force adding the top-level "native" object and support it in the initial adm field received from the bidder.

Please clarify in detail your use case of the native ad:

• (Optional) Bid Request
• (Mandatory) Bid Response from the Prebid Server with the bid in native format and the respective "adm" field
• (Mandatory) The code sample of Prebid SDK integration, which you use to manage the native ad

[AndrewHoang1995]

Hi @YuriyVelichkoPI,

Thank you for your response. I understand how the system works, but in the case when a bidder like InMobi returns a response that already contains a native object in the adm, I notice that reading it from the cache causes errors.

Below are the bid requests and responses I sent from the SDK:

• Bid Request :

sdk-request-native-inmobi.txt

• Bid Response :

sdk-response-native-inmobi.txt

And here is the code I am currently using:

After successfully receiving the bid, I notice that the ad from cache is null, which prevents the Prebid SDK from rendering the ad.

I would greatly appreciate support from the team on this issue.

Best regards,
AndrewHoang

[YuriyVelichkoPI]

Thanks for the clarification.

Two additional questions:

• Is this also relevant for iOS from a product perspective? I’m quite sure the answer is yes, but I’d like to formally confirm the scope “on paper.”
• Can the InMoby team contribute to supporting this type of markup? If yes, can you handle it for both platforms?

[AndrewHoang1995]

• The same issue occurs on iOS as well.

• I’m only using InMobi as a bidder, and I am not part of the InMobi team, but I am able to modify both the Android and iOS implementations.
  My temporary solution is to create a wrapper layer that re-parses the content to match your standard.
  However, I believe a fix made on your team’s side would be more effective.

[YuriyVelichkoPI]

Feel free to open PRs - the Prebid team will help adjust the solution if needed.

Prebid encourages community contributions as much as possible; this is the most efficient and proper way to move things forward. Otherwise, the task may sit in the queue for quite a while due to limited developers' bandwidth.

And thanks for reporting the issue!

[AndrewHoang1995]

I currently want to create PRs to fix this error, can you help me? When I push PR to a new branch, it is reporting an error about permissions.

[mdanylov-sigma]

I currently want to create PRs to fix this error, can you help me? When I push PR to a new branch, it is reporting an error about permissions.

Hey, @AndrewHoang1995! You just need to fork this repo, create and push that branch to your forked repo then open PR where select the master branch of the original repo as a base.