Using Google People API, one can get a contact detail by its ID.
"https://people.googleapis.com/v1/" + id + "?key=" + <KEY> + "&personFields=addresses,clientData,emailAddresses,names,organizations,phoneNumbers,birthdays",
Is it possible to get such details in batch? I have a list of 100 contact ids and I want them to get at once as it'd be much faster.
In your situation, how about using the method of "Method: people.getBatchGet"? When this method is used, the 200 resource names (maximum number) can be retrieved by one API call. When this is used for your situation, it becomes as follows.
curl \
'https://people.googleapis.com/v1/people:batchGet?personFields=addresses%2CclientData%2CemailAddresses%2Cnames%2Corganizations%2CphoneNumbers%2Cbirthdays&resourceNames=people%2Fsample1&resourceNames=people%2Fsample2&resourceNames=people%2Fsample3' \
--header 'Authorization: Bearer [YOUR_ACCESS_TOKEN]' \
--header 'Accept: application/json' \
--compressed
https://people.googleapis.com/v1/people:batchGet?personFields=addresses,clientData,emailAddresses,names,organizations,phoneNumbers,birthdays&resourceNames=people/sample1&resourceNames=people/sample2&resourceNames=people/sample3.