You can grab an instance of the underlying RKClient before making your request, and set Username and Password as follows:
// Set the Username and Password [RKObjectManager sharedManager].client.username = @"username"; [RKObjectManager sharedManager].client.password = @"letmein"; // Make our Request [[RKObjectManager sharedManager] getObject:user mapResponseWith:mapping delegate:self];
As MonkeyBonkey points out in the comments, you may need to force authentication using the flag:
[RKObjectManager sharedManager].client.forceBasicAuthentication = YES;
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