Does Lambda automatically check the message MD5 checksum when using an SQS trigger?

Question

Hi

I have found that the .NET SQS SDK automatically verifies the MD5 checksum of messages when retrieving messages from an SQS queue ([Source code link](https://github.com/aws/aws-sdk-net/blob/6bf2c51cafc608b141c269fc341eae616a39b5c6/sdk/src/Services/SQS/Custom/Internal/ValidationResponseHandler.cs#L321)). Does anyone know if Lambda will automatically do the same when using an SQS trigger to process messages?

Many thanks

Didier_Durand · Answer

Hi,

Lambda runtime execute the code that you define it to use. So, if your Lambda execute the code that you point to , yes, it will check md5 checksum by executing this code.

It's really dependent on what you choose: you could write your own code and not use the corresponding AWS SDK in your language of choice. In that case, you could do your own REST call to the SQS endpoint and decide to not check the md5 checksum (which is a bad idea, we agree...). But, it's possible.

So,  in summary, check of md5 checksum is left in your hands.

Best,

Didier

Does Lambda automatically check the message MD5 checksum when using an SQS trigger?

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