how irctc pnr status checking websites working ?
Indian rail have officially launched API for all the required information a developer may need. However there are limitations and policies to use the API for various security and load balancing purposes which one should take care.

Check out this page having details regading everything - Indian Railways API
How to Get IRCTC PNR STATUS API ?
The Indian
Railways IRCTC Timetable PNR Status Fare Live Status Indian
Railways API uses an API key to identify your application. API keys are managed
through the Indian Railways IRCTC Timetable PNR Status Fare Live Status APIs
console. To create your key:
Upon approval you will be provided with the API key
Once the service has been activated, you can make HTTP request to the API.
If you have an existing app or want to create
a new app related to Indian Railways, go ahead and checkout Indian Railways API. Full information is
available in their website.
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