Authentication without user credentials

I'm putting together a personal React site and want to send requests to an AWS API Gateway. However, I just want my site to be able to pull data. There will be no user model and every auth model I've ever used requires the user to do something with sign-in, be it user/pwd or AD. Can someone guide me to a model that covers this scenario?

One common approach is to use a Cognito Identity Pool with "Unauthenticated Identities" enabled. You can secure your API gateway endpoints using IAM, and require requests to be sig4 signed.

With this approach, Cognito is used only in a kind identity broker capacity, not as an actual identity provider. You do not need to create a User Pool or use any other identity management features of Cognito. In this capacity, Cognito is essentially just a thin layer between your code and the underlying STS APIs that produce the IAM keys your application needs.

Using the Cognito SDK, you request temporary IAM credentials (access key, secret key, session token) that can be used to sign the requests.

This answer outlines one way to accomplish this. When the protected AWS resource you want to access is API Gateway, your code may look something like the example near the end of this post.

I typically either use aws-api-gateway-client, as the example does, or aws4 with axios to sign requests.

As noted in the linked to answer above, I normally use AWS.config.credentials.get(), rather than AWS.CognitoIdentity.getCredentialsForIdentity() to actually get the IAM keys (as in this doc).

The signed requests then include an Authorization header that is very difficult to counterfeit. I don't want to suggest that this approach is bulletproof, but it does at least give you a reasonable level of confidence that your API Gateway endpoints are only being successfully invoked by your application.