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Cryptoprocessing Case Study: Crypto Payment Platform for Businesses

Link

HTTPS://KRASTERPAY.IOHTTPS://APP.KRASTERPAY.IO

Brief description

A crypto payment acceptance service for online businesses

Task

Build a system so a business can accept crypto payments and manage them in one place.

About the project

The project is a crypto processing platform for business: it accepts crypto payments from customers, records payment status, accounts for fees, stores operation history, and gives the store owner tools to manage funds.The platform solves “accept crypto as a payment method” in a form that is clear for business.Store onboarding: one account can run multiple projects/storefronts, each with its own key and settings.Crypto payment tied to fiat: issue an invoice in USD (or another currency) equivalent, and the customer pays in a chosen crypto at the current rate. Time-bound payment control: invoices have an expiry timer to avoid stuck payments and reduce loss risk from volatility/delays.Wallet and fund management: top-ups, balances across assets, withdrawal to an external address; all transaction logic is transparent and stored in history.Operational and financial admin: user, withdrawal, and transaction management, fee/discount settings, plus aggregate turnover and platform revenue metrics.A single product that connects crypto payment acceptance (API/links), transaction accounting and statuses, balance management, and administrative control — so a business can accept crypto systematically, not “manually in a wallet.”

Business benefits

•SHARE OF PAID INVOICES GREW BY 60% THANKS TO THE NEW CRYPTO PAYMENT METHOD
•QUARTERLY REVENUE GROWTH DYNAMICS STAYED AT 500% THANKS TO FEES, DISCOUNT SETTINGS, AND NEW MERCHANT ONBOARDING

Features

•User creates a store in the personal account
•Unique API key generation
•Store name assignment
•Method list
•Request and response formats
•Integration scenarios
•Payment link generation
•Payment in a specific cryptocurrency
•USD-equivalent payment with currency choice by the customer
•Payment time limit
•Recurring payments (by contract)
•Approve issuance
•Automatic monthly charging
•Add a fee +%
•Configure a discount -%
•Flexible monetization model
•Optional automatic conversion to a stablecoin
•USD value lock
•Automatic creation of new addresses for users
•Registration
•Password change
•Top-up
•Withdrawal
•Account creation via email and password
•Password recovery
•2FA setup
•Profit display
•Rate change dynamics
•Operations analytics
•Total balance display
•USD conversion
•Conversion into 12+ currencies
•Deposit address generation
•Automatic crediting
•Currency selection
•Address input
•Manual withdrawal moderation
•Date
•Store
•Amount
•Currency
•Status
•Cryptocurrency exchange
•Platform fee
•Available currency list management
•Required personal data collection
•Identity document upload
•Data correctness checks
•Statuses: unverified / under review / approved / rejected
•Additional document requests
•Feature limits (deposits/withdrawals/limits) until KYC is complete
•Base limits for users without KYC
•Higher limits for verified users
•Extra checks for large operations
•Hot and cold wallet separation
•Hot wallets for daily operations
•Cold wallets for long-term storage
•Balance per wallet
•Withdrawal availability control
•Full operation logging
•Automatic hot wallet top-up
•Minimum balance threshold control
•Transfer from cold storage when needed
•Access restrictions
•Separate rights for viewing and executing transactions
•Confirmation of critical operations
•Automatic network fee calculation
•Gas reserve
•Gas limit settings
•Cost optimization
•Incoming transaction checks via an AML provider
•Sender address risk assessment
•Sanctions lists and high-risk category checks
•Assign a risk-score to a transaction
•Risk levels: low / medium / high
•Check status display in the system
•Automatic crediting at low risk
•Move transaction to “under review” at medium/high risk
•Block crediting at critical risk
•AML analysis of the address before withdrawal
•Check for links to banned services or sanctioned entities
•Automatic pause of suspicious operations
•Hand-off to manual moderation
•Admin ability to reject a withdrawal
•User registry
•Block/unblock
•Manual balance change
•View all transactions
•Request list
•Manual processing
•Withdrawal history
•Send funds to multiple addresses
•Wallet balance checks
•Send cryptocurrency
•Deposit address management
•Total turnover
•Fee profit
•Metric charts
•Check result display
•Access to risk-score and details
•Check history per user
•Filter transactions by risk level
•Manual approve or reject operations
•Temporary user block
•Record all AML checks
•Store data for internal audit
•Configurable acceptable risk thresholds
•Flexible enable/disable of automatic blocks
•Integration with external AML services
•Super Admin — full access
•Finance operator — deposit/withdrawal processing
•Compliance officer — KYC/AML checks
•Content manager — UI/store management
•Analyst — statistics access
•Separation by sections
•Separation by action type (view / edit / confirm)
•Staff action logging
•Change journal
•Approve/reject history
•Responsible employee recording
•Percentage fee settings
•Add or subtract a percentage from a payment
•Fixed amount in cryptocurrency
•USD amount with rate conversion
•Payment timer setup
•Automatic close of an expired invoice
•Recommendations for hot/cold wallet separation
•Access control to funds
•Manual operations regulations

Technology stack

•React
•MobX
•ASP.NET Core — server application foundation
•Entity Framework — ORM
•Hangfire — background jobs
•MailKit and MimeKit — email
•Clean Architecture
•MediatR — CQRS for queries and commands
•Swashbuckle — OpenAPI/Swagger docs
•QuickNode — blockchain access
•BitOk — AML checks
•AWS SDK — Amazon S3
•Bybit — rates and currencies
•Coingecko — rates and currencies
•PostgreSQL — primary database
•Docker
•ELK Stack
•TeamCity
•Serilog — logging and monitoring

Working with the client

*Important: this is not project delivery work — it is work with the client specifically, and it is not in the estimate or commercial proposal; it is what we do to raise the product’s chance of successSystematic knowledge transfer: from vulnerabilities to growth pointsFor us it matters that after delivery the client is not left alone with market reality. So in parallel with development we built a separate competency-transfer track. The Defence.investments team walked the client through the product’s business architecture in detail: how metrics interconnect, where cash gaps form, which user actions signal upcoming churn. Separately we covered the marketing touch chain that converts now, not a year ago. As a result the project owner got not only a technical platform, but the ability to diagnose business health and anticipate critical forks — moving into a strategist role.Our goal is not just development — it is our client’s success.

Design goals:

•MAKE CRYPTO PAYMENT FEEL AS CLEAR AS A REGULAR INVOICE, SO IT IS FAMILIAR TO THE USER
•MAKE KEY ACTIONS VISIBLE: CREATE INVOICE, WITHDRAW, GENERATE LINK
•SHORTEN THE PATH TO RESULT: CREATE INVOICE → SEND LINK → SEE PAYMENT IN ONE PLACE
•HTTPS://WWW.FIGMA.COM/DESIGN/G9Y9Y6XLXHZ2MZXJFKUDQE/-IN-PROCESS--KRASTER-WALLET-PAY?NODE-ID=4-90&T=XZDIVXGJS49Q6ALC-1

Design results:

•A UNIFIED MERCHANT CABINET WITH A CLEAR STRUCTURE: STORES, INVOICES, TRANSACTIONS, WALLET
•CLEAR PAYMENT STATUSES AND AN INVOICE TIMER — YOU SEE WHAT IS HAPPENING RIGHT NOW
•FAST PAYMENT-LINK CREATION WITHOUT EXTRA FIELDS, SO IT CAN BE SENT TO A CLIENT IN A MINUTE
•A DASHBOARD WITH CORE NUMBERS WITHOUT OVERLOAD, SO THE OWNER INSTANTLY UNDERSTANDS PAYMENT OUTCOMES
•CAREFUL SECURITY PRESENTATION (2FA, ACCESS RECOVERY) WITHOUT COMPLEX WORDING