Payments / Intermediate / 5 min
Offline payments: store and forward
Shops keep taking small payments while offline and sync later. An offline limit caps the loss from customers who overspend.
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In short
- What it is
- Offline payments let a terminal accept a payment without reaching the server, store it securely, and forward it when the network returns.
- Why it matters
- Shops in places with weak networks still need to sell, and a dropped connection should not stop every sale.
- The trade-off
- Without a live balance check the same money can be spent twice; small offline limits (and signed, tamper-proof records) cap the loss.
- Say it in an interview
- "Signed offline receipts in a local queue, a low per-customer offline limit, idempotent sync on reconnect, and the merchant carries the small capped risk."
Check yourself
What does "store and forward" mean for offline payments?
Answer: The terminal saves the payment and sends it to the server when the network returns. Sales continue during an outage; the stored payments are forwarded and settled later.
What is the main risk of accepting payments offline?
Answer: A customer can spend more than their balance across shops that cannot check it. Nobody can see the real balance while offline, so the same money can be spent twice (double spend).
How do systems like UPI Lite limit that risk?
Answer: A small offline limit per customer caps the possible loss. Low per-payment and per-wallet limits keep the worst case small while still allowing everyday offline purchases.