Indian Postal adds an Indian PIN code and Post Office master to Frappe/ERPNext and wires it into the standard Address doctype. Enter a 6-digit PIN code on any Address and the app automatically fills in the Post Office, Branch Type, Delivery Status, Circle, District, Division, Region, Block, State and Country, sourced from India Post's own PIN code directory.

Lookups are served from a local cache first. The public PostalPincode API is only called on a cache miss, and every response it returns is saved back to the cache, so a given PIN code is fetched from the internet at most once across your entire site. Every later lookup, on any Address, by any user, is a local database read.

The external API is never called from the browser. Every request is routed through a whitelisted server-side method, which keeps the integration point centralized, avoids CORS issues, and lets Address entry keep working off cached data even if the external service is slow or temporarily unavailable.

Key features:

• Auto-fill on PIN code entry, no manual typing or copy-pasting from the India Post website

• A selection dialog when a PIN code covers more than one Post Office, which is common in India

• A searchable Post Office field, filtered to the entered PIN code, searchable by name, PIN code, district or state

• A manual refresh option for re-fetching from the API on demand

• Friendly, plain-language error messages instead of tracebacks for invalid PIN codes, timeouts, or an unreachable API

• Implemented entirely through custom fields, a custom doctype, and client/server scripts, no ERPNext core file is modified