Glossary · Finance & banking
Switch file vs CBS (core banking) data meaning
A switch file is the bank's log of card, ATM and UPI transactions from its payment switch. See how it differs from core banking data and why both are matched.
What is a switch file in banking?
Every digital payment a bank handles passes through its switch before anything is posted. The switch receives the request from the network or channel, checks it, sends it to the core for authorisation and records the response. At the end of a cycle it writes out a file of everything it saw: the reference number, amount, time stamp, response code and status for each transaction. That file is the switch file, sometimes called the switch report or switch log.
Core banking data is a different record. It shows what the CBS actually debited or credited to customer accounts and which GL heads moved. On a perfect day the two agree line for line. In practice they rarely do, because time-outs, reversals and late responses create gaps.
How is switch data different from CBS data?
| Point | Switch file | CBS data |
|---|---|---|
| What it records | Messages routed and their response codes | Postings to accounts and GL |
| Typical key | RRN, terminal or VPA, time stamp | Account number, journal number, narration |
| Common gap | Shows success where the core timed out | Shows a debit where the switch logged a failure |
A third source usually joins them: the network settlement file (for UPI and IMPS, the NPCI settlement reports). A full recon is therefore three-way, switch against CBS against network, so that each transaction is confirmed by the system that routed it, the system that posted it and the system that settled it.
What does a switch vs CBS mismatch look like?
Illustrative example with simple numbers. On one day the switch file shows 1,000 UPI debits. CBS shows 997 debits posted. Matching on RRN and amount finds:
- 995 transactions present on both sides with the same amount: matched.
- 5 transactions marked successful at the switch but missing in CBS: the customer may have been told the payment went through while no debit happened, or the posting sits in a suspense head.
- 2 debits in CBS whose switch status is a time-out or decline: these are candidates for a customer refund or an auto-reversal check.
Each of the seven unmatched lines becomes a break with an owner and an age. Teams that run this daily on UPI reconciliation software for banks can see which break types repeat and write a rule for them instead of clearing them by hand every morning.
What mistakes do teams make with switch files?
- Matching on amount alone. Many UPI payments share the same amount. The RRN, or RRN plus date, is the safer key; see exact, tolerance and fuzzy matching rules.
- Ignoring the cut-off. A transaction at 11:58 pm may sit in today's switch file and tomorrow's CBS posting. Without a cut-off rule it shows as two breaks.
- Treating the switch file as the truth. The switch knows what it routed, not what the customer's account shows. Both views are needed.
- Clearing reversals twice. A failed transaction and its reversal are two lines in CBS but one event. Pair them before calling anything a break.
For the wider UPI flow, including network settlement, read UPI reconciliation for banks, NBFCs and PSPs.
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Questions
What is a switch file in UPI reconciliation?
It is the log from the bank's payment switch listing every UPI request it routed, with the RRN, amount, time and response code. Recon teams match it against core banking postings and the NPCI settlement files.
Why do switch and CBS data not match?
Usually because of time-outs, late responses, reversals and day-end cut-offs. The switch may record a success that never posted in the core, or the core may post a debit the switch logged as failed.
What is three-way reconciliation in banking?
It means matching the same transaction across three records: the switch file, the core banking postings and the network settlement file. A transaction is cleared only when all three agree on reference and amount.