A Razorpay payout is never the sum of your invoices. Fees, GST on fees, refunds and timing all sit
A settlement bundles many payments, minus Razorpay's fee and 18 percent GST on that fee, minus refunds, so the bank credit never equals invoice totals.
The payment id and the order id are the only reliable keys; customer name and amount alone produce false matches.
Your GST liability is on the full invoice value, not on the net settled amount; the fee is an expense on which you can claim ITC against Razorpay's invoice.
Automated reconciliation matches payment ids to invoices and leaves only the exceptions, usually refunds and unlinked payments, for a person to resolve.
It is the process of matching each amount Razorpay credits to your bank account with the customer payments inside it, and then matching those payments to the invoices you issued.
The full guide has the formats, the deadlines and the worked examples.