QR code payment app: 50,000+ downloads within the first six months of launch

Innowise has developed a mobile app that enables quick and secure QR code-based transactions between users and merchants.

Customer

Industry

Finance

Region

Client since

2023

Our client, a US-based FinTech startup, aimed to create a QR code payment app that makes shopping easier and payments smoother. Their vision was to provide a fast, secure, and user-friendly payment solution that integrates with banking systems and digital wallets.

Detailed information about the client cannot be disclosed under the provisions of the NDA.

Challenge

The client required a robust and scalable mobile QR payment app that could:

Process QR code payments, automatically deducting small amounts while requiring confirmation for larger transactions.
Integrate with banking APIs (RTP, ACH + NACHA).
Work seamlessly on iOS and Android and support Google Wallet and Apple Wallet for digital payment cards, stored and processed as secure tokens.
Scale with a microservices-based backend.
Incorporate secure authentication and fraud detection mechanisms.

Solution

We built a QR code payment app designed around the client’s vision. The APIs enable real-time transactions and seamless bank connections, which allow users to pay quickly and securely at merchants.

How it works

The user initiates a payment by scanning a QR code displayed at the point of sale.
The app retrieves transaction details from the QR code, including the merchant's information and payment amount.
If the payment amount is below a predefined threshold, the system automatically deducts the amount from the user's linked payment method without requiring confirmation.
For larger transactions, the app prompts the user to confirm the payment via biometric authentication or PIN entry.
Once confirmed, the payment request is securely transmitted through the backend, utilizing banking APIs for fund transfers.
The transaction is verified and recorded in the blockchain-based ledger for added security and transparency.
Upon successful payment, a confirmation message is displayed to the user.
The user can view transaction history and manage their digital wallets within the app.

We’ve built the app on robust technology, smart automation, and rock-solid security. From instant QR payments and biometric authentication to blockchain-backed security, here’s what drives the app under the hood:

QR code payments

The core functionality of the mobile app revolves around enabling quick and secure QR code-based transactions and offering multiple payment options.

Users can scan QR codes at retail stores to initiate payments instantly. Transactions below a predefined threshold are automatically processed, while larger transactions require authentication through biometric login (Face ID, fingerprint) or a secure PIN entry.
QR code payment app supports a variety of payment methods. The users can link their bank accounts via open banking APIs, add credit and debit cards through tokens, and use digital wallets such as Google Pay and Apple Pay.

User experience

We designed an intuitive interface to enable effortless transactions for users and equip them with comprehensive tools for managing payments and tracking analytics.

The mobile app features a sleek and user-friendly interface designed for fast QR code scanning, transaction management, and wallet integration. The app uses real-time transaction updates and push notifications to keep users informed of their payment status.
Users can access transaction history with detailed breakdowns, including timestamps, merchants, and payment methods. Digital receipts are automatically generated and can be shared via email or saved in the app for future reference.

Security and compliance

QR code payment app prioritizes security and compliance by incorporating advanced authentication mechanisms, blockchain-based security, and adherence to financial regulations.

The app employs multi-factor authentication (MFA), which includes a biometric login, a PIN, and one-time passwords (OTP) sent via SMS or email. AI-driven fraud detection systems monitor transaction patterns and flag suspicious activity to prevent unauthorized access.
The app uses Hyperledger Aries for decentralized identity management. It provides secure and private authentication through self-sovereign identity (SSI) wallets, which give users full control over their credentials instead of relying on vulnerable centralized databases. Each transaction gets cryptographically signed and recorded on a blockchain-based ledger. This creates an immutable, verifiable, and tamper-proof record of every payment, making fraud and unauthorized changes nearly impossible.
The mobile app adheres to US banking regulations, including RTP (Real-Time Payments), ACH (Automated Clearing House), and NACHA (National Automated Clearing House Association) protocols. It complies with anti-money laundering (AML) and Know Your Customer (KYC) policies and integrates identity verification services.

Scalable architecture and infrastructure

The backend architecture was designed to be modular, scalable, and optimized for high performance under heavy transaction loads.

The app runs on a microservices architecture, so services like transaction processing, authentication, and payment reconciliation can scale independently. This makes it more reliable and ready for future growth.
By moving from serverless and VM containers to Google Kubernetes Engine (GKE), we’ve boosted performance and cost-efficiency, while container orchestration keeps everything scalable and resilient.
The system fully supports Google Wallet and Apple Wallet. Secure tokenization of payment credentials powers seamless digital wallet transactions.

Automated deployment and maintenance

Automation and performance optimizations were incorporated to speed up operations and provide a frictionless user experience.

QR payment app employs continuous integration and continuous deployment (CI/CD) pipelines for automated software updates, reducing downtime and accelerating feature rollouts. Automated testing and monitoring help keep the system stable.
We optimized transaction processing speeds to cut delays and make the system more reliable under heavy loads. Caching mechanisms and load balancing help manage API requests efficiently.

Technologies

Backend

Go (Gin, Gorm, gRPC, gcp-log), Ruby (legacy code only, Sinatra), PostgreSQL, Redis (key/value storage, pub-sub, streams), Hyperledger Aries

Frontend

TypeScript, SWR, SASS & MUI, Final-Form, Next.js 13

Mobile development

Java

Cloud & DevOps

Google Cloud Platform (IAM, CloudRun, VM), Docker

Digital Wallets

TypeScript, SWR, SASS & MUI, Final-Form, Next.js 13

Development environment & tools

Jira, Notion, GitHub, Gmail, Google Chats/Spaces

Team

Project Manager

Go Developers

React Developers

Flutter Developer

DevOps Engineer

QA Engineer

UX/UI Designer

Results

Innowise developed a fast, contactless QR code payment mobile app, enabling transactions between customers and merchants. Within the first three months after launch, over 500 merchants onboarded, quickly adopting the system due to its easy QR code generation and hassle-free banking integration.
The integration with multiple bank APIs allowed flexible fund settlements, instant transactions, and seamless switching between banking partners.

The app’s availability on both App Store and Google Play, along with full support for Apple Wallet and Google Wallet, contributed to high adoption rates among users. Within the first six months, the app was downloaded over 50,000 times, earning a 4+ rating across both platforms.

Project duration

August 2023 - Ongoing

500+

merchants joined in the first six months

50,000+

downloads post-launch

Related cases

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