Short answer: there isn’t one “best” app for everyone — rewards depend on how you spend. The apps most frequently offering the biggest, redeemable rewards and merchant cashbacks in Sri Lanka are:

• Commercial Bank (ComBank Digital + Q+ Payment App) — strong loyalty/points (ComBank Max Rewards) plus frequent QR/cashback campaigns via the Q+ app. Good if you want bank points that convert to rupees or travel/hotel redemptions. (combank.lk, cbr.lk)

• Sampath Bank (Sampath WePay + Sampath card rewards / Ultrarewards) — WePay is convenient for LankaQR and bill payments and Sampath’s card reward programme gives points you can redeem across vouchers, flights and hotels. Good if you use a Sampath credit card regularly. (sampath.lk, loyalty.sampathbank.lk)

• HNB (HNB mobile / Genie ecosystem) — frequent partner cashback and merchant promos for HNB cardholders (examples include app-specific cashback offers). Good for targeted merchant discounts. (hnb.net)

• FriMi (Nations Trust Bank’s FriMi) — a popular digital-first wallet/app with ongoing promotional rewards, virtual cards and lifestyle offers; useful if you prefer a modern wallet with rotating promos. (frimi.lk)

• iPay / LOLC iPay and other payment platforms (mCash, iPay, iPay merchant deals) — strong on merchant discounts, aggregator deals and frequent limited-time promos (good if you chase merchant cashbacks). (ipay.lk, lolcfinance.com)

Tips to pick the best for you

• If you want bank points redeemable like cash or travel: lean ComBank or Sampath (card + digital platform). (combank.lk, loyalty.sampathbank.lk)
• If you use LankaQR / in-person merchant payments and want occasional big cashbacks: watch Q+, WePay, iPay and mCash promo pages (these run time-limited campaigns). (cbr.lk, sampath.lk, ipay.lk)
• Read terms: rewards are often time-limited, capped per transaction/day and tied to specific cards or merchant categories. Check each app’s Rewards/Promotions page before relying on an offer.

If you want, I can run a live check of current (today’s) cashback/promotional offers across two or three specific apps and give a short comparison.