I have built an API to validate Indian pincodes (zipcodes). This API will return the city and state when provided with a pincode. In the event of a wrong or invalid pincode the API throws an error.
Developers who are building applications for Indian users can find this API useful to ensure that the users are providing the right pincodes.
Website: https://indianpincodes.co.in/
API example: https://indianpincodes.co.in/api/pincode?code=110001