BumpWallet
Tap to Pay NFC Wallet
Created on 14th March 2026
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BumpWallet
Tap to Pay NFC Wallet
The problem BumpWallet solves
The Problem
Onchain payments are still far more complicated than everyday digital payments.
Today, sending crypto usually requires users to:
- Copy and paste long wallet addresses
- Scan QR codes
- Switch between multiple apps
- Manually choose chains and tokens
- Risk sending funds to the wrong address
These steps introduce friction, confusion, and irreversible mistakes, especially for non-crypto users. Paying someone in crypto should be as simple as tapping a card — but today it isn’t.
The Solution
Bump makes onchain payments feel like contactless payments.
Instead of copying addresses or scanning QR codes, users simply tap phones using NFC to send crypto instantly.
Bump combines identity, payments, and merchant checkout into a single mobile app.
What People Can Use It For
🤝 Peer-to-Peer Payments
Send stablecoins to friends, roommates, freelancers, or sellers by simply tapping phones.
Perfect for:
- Splitting bills
- Paying someone back instantly
- Creator or freelancer payments
- Informal commerce at events or hackathons
🛍️ Merchant Checkout (Phone-Based POS)
Bump includes a merchant mode, turning any phone into a crypto checkout terminal.
Merchants can:
- Add items to a simple POS cart
- Generate a payment request
- Let customers tap to approve and pay
- Instantly confirm payment
- Keep a simple transaction history
No hardware terminals or integrations required.
🪪 Human-Readable Payment Identity
Users can claim a *.bump.eth
Instead of sending to a long wallet address like:
0xabc123...9f2
Users pay something recognizable like:
alice.bump.eth
This makes payments more trustworthy and reduces mistakes.
📒 Clear Payment History
Bump keeps a readable record of payments and syncs them to a Fileverse-backed ledger, helping users:
- Track payments and receipts
- Review past transactions
- Treat crypto payments like normal financial activity
Why It’s Better
Bump improves crypto payments by making them:
- Faster — tap-to-pay instead of copy/paste
- Safer — ENS identities reduce address mistakes
- More familiar — uses the same “tap to pay” interaction people already understand
- All-in-one — wallet, identity, payments, POS, and transaction history in a single app
In Short
Bump turns crypto payments into a simple, real-world interaction: tap phones and pay.
Challenges we ran into
Challenges I Ran Into
NFC Tap-to-Pay Between Phones
Implementing tap-to-pay required handling Android NFC at a low level, including reader mode for the payer and Host Card Emulation (HCE) for the merchant.
Solution
I built custom Android native modules and designed a simple NFC protocol with session IDs and structured payment payloads to ensure reliable tap interactions.
Reliable Payment Confirmation
Blockchain events alone can be unreliable due to websocket failures or delayed receipts.
Solution
I implemented multiple confirmation layers:
- realtime event watchers
- transaction receipt checks
- transfer log validation
- polling fallback
This ensures payments are confirmed even if one mechanism fails.
Preventing Replay Attacks in NFC Payments
A simple NFC transfer could allow replay attacks or unsigned payment requests.
Solution
Payments use EIP-712 signed authorizations verified by an onchain contract with nonce and deadline checks, supporting both EOAs and ERC-1271 smart wallets.
Tracks Applied (5)
DeFi
Best creative use of ENS
Ethereum Name Service
Best Privacy Application using BitGo
BitGo
DeFi 2.0 - New Primitives
Base
BEST Overall Project
Technologies used
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