Hi, I’ve added attestation to my app, and everything worked as expected during setup. However, after deployment, I noticed some unknownSystemFailure entries in the production logs on New Relic. Could you help me understand what typically causes this error? The documentation suggests issues such as failing to generate a token. What scenarios could lead to that?

From watching the video on App Attest the answer would appear to be no, but the video is a few years old so in hope, I thought I would post this question anyway. There's several scenarios where I would like a notification service extension to be able to use App Attest in communications with the back end(for example to send a receipt to the backend acknowledging receipt of the push, fetching an image from a url in the push payload, a few others). Any change App Attest can be used in by a notification service extension?

Hello, we are using DeviceCheck – App Attest in a production iOS app. The integration has been live for some time and works correctly for most users, but a small subset of users encounter non-deterministic failures that we are unable to reproduce internally. Environment iOS 14+ Real devices only (no simulator) App Attest capability enabled Correct App ID, Team ID and App Attest entitlement Production environment Relevant code let service = DCAppAttestService.shared service.generateKey { keyId, error in // key generation } service.attestKey(keyId, clientDataHash: hash) { attestation, error in // ERROR: com.apple.devicecheck.error 3 / 4 } service.generateAssertion(keyId, clientDataHash: clientDataHash) { assertion, error in // ERROR: com.apple.devicecheck.error 3 / 4 } For some users we intermittently receive: com.apple.devicecheck.error error 3 com.apple.devicecheck.error error 4 Characteristics: appears random affects only some users/devices sometimes resolves after time or reinstall not reproducible on our test devices NSError contains no additional diagnostic info Some questions: What is the official meaning of App Attest errors 3 and 4? Are these errors related to key state, device conditions, throttling, or transient App Attest service issues? Is there any recommended way to debug or gain more insight when this happens in production? Any guidance would be greatly appreciated, as this impacts real users and is difficult to diagnose. Thank you.

Hi, In our app we are using DeviceCheck (App Attest) in a production environment iOS. The service works correctly for most users, but a user reported failure in a flow that use device check service. This failure is not intermittently, it is constant. We are unable to reproduce this failure and we are believing that this failure occurred by new version ios 26.3 because for others users using early versions the service is normally. Environment iOS 26.3 Real device App Attest capability enabled Correct App ID, Team ID and App Attest entitlement Production environment Characteristics: appears constantly affects only unique user -Don't resolves after time or reinstall not reproducible on our test devices NSError contains no additional diagnostic info (Error Domain=com.apple.devicecheck.error Code=3 "(null)") We saw about this error code 3 in this post 812308, but it's not our case because the ios version in this case is not iOS 17.0 or earlier. Please, help us any guidance for solution. Thank you

I’m looking for clarification on how rate limiting works for the App Attest service, especially in production environments. According to the entitlement documentation (https://developer.apple.com/documentation/BundleResources/Entitlements/com.apple.developer.devicecheck.appattest-environment), iOS ignores the environment setting once an app is distributed through TestFlight, the App Store, or Enterprise distribution, and always contacts the production App Attest endpoint. With that context, I have two questions: Rate‑Limiting Thresholds How exactly does rate limiting work for App Attest? Is there a defined threshold beyond which attestation requests begin to fail? The "Preparing to Use the App Attest Service" documentation (https://developer.apple.com/documentation/devicecheck/preparing-to-use-the-app-attest-service) recommends ramping up no more than 10 million users per day per app, but I’m trying to understand what practical limits or failure conditions developers should expect. Per‑AppID Budgeting If multiple apps have different App IDs, do they each receive their own independent attestation budget/rate limit? Or is the rate limiting shared across all apps under the same developer account?

Hi, We are implementing Platform SSO and using attestKey during registration via ASAuthorizationProviderExtensionLoginManager. Could you clarify whether the attestKey flow involves sending attestation data to an Apple server for verification (similar to App Attest in the DeviceCheck framework), or if the attestation certificate chain is generated and signed entirely on-device without any Apple server interaction? The App Attest flow is clearly documented as using Apple’s attestation service, but the Platform SSO process is less clearly described. Thank you.

I'm trying to confirm the correct URL for Apple Attest development. There seems to be a fraud metric risk section that uses this: https://data-development.appattest.apple.com/v1/attestationData However the key verification seems to use this: https://data-development.appattest.apple.com/v1/attestation Currently I'm attempting to verify the key, so the second one seems likely. However I keep receiving a 404 despite vigorous validation of all fields included in the JSON as well as headers. Can anyone confirm please, which URL I should be sending my AppleAttestationRequest to?

I'm currently reviewing the various DCError cases defined in Apple’s DeviceCheck framework (reference: https://developer.apple.com/documentation/devicecheck/dcerror-swift.struct). To better understand how to handle these in production, I’m looking for a clear breakdown of: Which specific DCError values can occur during service.generateKey, service.attestKey, and service.generateAssertion The realworld scenarios or conditions that typically cause each error for each method. If anyone has insight on how these errors arise and what conditions trigger them, I’d appreciate your input.

Hi there, We're implementing Apple's DeviceCheck App Attest for production iOS authentication. The public documentation defines DCError cases but doesn't specify which errors are expected per API method or recommend retry/remediation strategies. We need Apple's guidance to implement robust, production-aligned error handling before rollout. 1. Error Surface per API Method Question: Can you confirm the complete, officially expected set of DCError values for each method? We understand the following errors are possible across App Attest APIs: invalidKey invalidInput featureUnsupported serverUnavailable unknownSystemFailure Specifically, please confirm which errors can occur for: DCAppAttestService.generateKey() DCAppAttestService.attestKey(_:clientData:) DCAppAttestService.generateAssertion(keyID:clientData:) Are there any additional undocumented or edge-case errors we should handle? 2. Retry Strategy & Remediation Matrix Question: For each API method and error code, please help us with proposal around which errorCode is retriable, whats the remediation pre retry, retry cap and backoff strategy: Kindly also help with errors that are not covered here: Specific sub-questions: invalidKey handling: When this error occurs: Should the app delete the key and call generateKey again? Or should it fail the entire flow? serverUnavailable handling: Should we retry immediately, or wait before retrying? Is exponential backoff recommended? What's the recommended max retry count? Backoff strategy: Which errors (if any) qualify for exponential backoff? Recommended base delay, max delay, and jitter approach? When should we give up and fail the request? unknownSystemFailure: Is this retriable or should we fail? Any known causes or mitigations? 3. Simulator Testing Questions: Simulator API behavior: Can App Attest APIs be called normally on iOS Simulator? If not, is there a way to simulate for testing. Do they complete successfully with simulated attestations, or do they fail? Thanks, Nirekshitha