A payment processor and a general ledger are both authoritative for something, and neither is authoritative for the thing in between: which invoice a given deposit actually paid. That gap is where a surprising amount of manual reconciliation work quietly lives.
Stripe and Razorpay are excellent at the job they do — moving money and recording that a charge succeeded. They are not built to know that a partial payment of ₹41,250 was actually the customer paying two invoices short by a rounding difference, or that a payment labelled with a personal name in the bank feed corresponds to a company account because that is how the finance controller's bank happens to display it. Matching that requires comparing against the billed party's name and contact details, not just an exact string match on a payer field — otherwise you get an "unmatched transaction" pile that grows every week and nobody trusts the aging report because nobody knows how much of it is actually still owed.
On the ledger side, the failure mode is different. An ERP wants clean journal entries: debits equal credits, dated correctly, traceable to a source document. If the billing layer hands it a number without a path back to the invoice or shipment that produced it, every audit becomes an archaeology project. The fix is not a fancier sync job — it's making sure the billing system produces journal-ready entries with the trail attached before anything crosses the wire to the ERP, so the integration is a transport step, not a translation step.
The honest measure of whether an integration is working is not "did the API call succeed." It's whether a controller can start from a bank statement line, walk to the invoice it paid, and walk from there to the journal entry it posted, without opening three tools and asking someone in ops to remember what happened in March.