---
title: "What does signatureVerificationFailed (code 37) mean in the purchases SDK?"
description: "signatureVerificationFailed (code 37 on iOS, 36 on Android) means a response failed the SDK's signature check. It is thrown only when verification is enforced."
url: https://revenuedot.app/docs/errors/sdk-signature-verification-failed
---

# What does signatureVerificationFailed (code 37) mean in the purchases SDK?

The purchases SDK raises signatureVerificationFailed (code 37 on iOS, 36 on Android) when a response fails the signature check and verification is enforced.

## Quick facts

| | |
|---|---|
| Error | `ErrorCode.signatureVerificationFailed` (iOS), `PurchasesErrorCode.SignatureVerificationError` (Android), code 37 |
| Where | Purchases SDK (iOS, Android and the hybrid SDKs built on them) |
| What the vendor says | Request failed signature verification. |

## Cause

- iOS: a response failed verification while the SDK was in enforced mode. In any other mode the SDK logs the failure and carries on.
- Android: a `SignatureVerificationException` becomes `SignatureVerificationError`, numbered 36 on Android and 37 on iOS.
- A server that does not sign with the key the SDK trusts. The stock SDK trusts only RevenueCat's key, and a proxy that rewrites responses breaks the signature too.

## Fix

1. Turn verification off in the SDK configuration (disabled mode). Native iOS and Android default to informational mode, which only logs a failure.
2. Never use enforced mode with the stock SDK against RevenueDot: it would reject every response.
3. Or build the RevenueDot forks with your server's public signing key to get verified responses.
4. Compare the key at `GET /.well-known/revenuedot-signing-key` with the key in your SDK build.

## Example

```swift
// The purchases SDK throws `ErrorCode` values; match the one you handle and let the rest fall through.
func handle(_ error: Error) {
    guard let code = error as? ErrorCode else {
        print("Not a purchases SDK error: \(error)")
        return
    }
    switch code {
    case .signatureVerificationFailed:
        // In informational mode nothing is thrown; with enforcement on, never unlock from this response.
        print("Signature verification failed")
    default:
        print("Other purchases error: \(code.description)")
    }
}
```

*Compile-checked: `npm run check:snippets` type-checks this snippet with `swiftc` together with the `ErrorCode.swift` file of the RevenueDot `purchases-ios` fork (checked 2026-10-03).*

## How the RevenueDot SDK reports it

RevenueDot signs 2xx and 3xx responses under `/v1` when `REVENUEDOT_SIGNING_KEY` is set. See [signature verification failed in proxy mode](https://revenuedot.app/docs/help/signature-verification-failed.md). Deep dive: [revenuedot.app/errors/signature-verification-failed](https://revenuedot.app/errors/signature-verification-failed).

## Related

- [What does invalidCredentialsError (code 11) mean in the purchases SDK?](https://revenuedot.app/docs/errors/sdk-invalid-credentials-error.md)
- [What does invalidReceiptError (code 8) mean in the purchases SDK?](https://revenuedot.app/docs/errors/sdk-invalid-receipt-error.md)
- [What does VerificationError.invalidSignature mean in StoreKit 2?](https://revenuedot.app/docs/errors/storekit-verification-error-invalid-signature.md)
- [What RevenueDot's API errors mean (server codes)](https://revenuedot.app/docs/api/errors.md)

## Source

- [RevenueDot purchases-ios: ErrorCode.swift (the iOS ErrorCode enum)](https://github.com/revenuedot/purchases-ios/blob/revenuedot/main-patches/Sources/Generated/ErrorCode.swift)
- [RevenueDot purchases-android: PurchasesErrorCode.kt (the Android enum)](https://github.com/revenuedot/purchases-android/blob/revenuedot/main-patches/purchases/src/main/kotlin/generated/com/revenuecat/purchases/PurchasesErrorCode.kt)
- [RevenueDot purchases-android: common/errors.kt (backend code mapping)](https://github.com/revenuedot/purchases-android/blob/revenuedot/main-patches/purchases/src/main/kotlin/com/revenuecat/purchases/common/errors.kt)

Checked: 2026-10-03