HOLM Case Study: E-commerce Platform With Product Draws

Creating a user account and signing into the personal cabinet

Password recovery

Managing basic profile data

Profile: contacts, delivery address(es), notification settings

Order history and delivery statuses

Lottery participation history and purchased tickets

Viewing wins and prize issuance status

Product listing by the administrator

Creating a product card: name, description, photo/gallery, specifications

Availability management: stock, limits, unpublishing

Product categorization (binding to categories and tags)

Product showcase with sorting and quick card preview

Display of price, availability, purchase and delivery terms

Catalog search

Category and subcategory hierarchy

Filters by parameters (category, price, availability, brand/type — based on product logic)

Sorting (popular, new, price)

Full description, photo gallery, specifications

Display of availability and purchase terms

Add-to-cart button and quick transition to checkout

Cart: changing quantity, removing a product, recalculating the total

Checkout: delivery address, recipient details, delivery method selection

Order confirmation and “accepted for processing” status

Order payment via a payment solution

Order statuses: created, paid, processing, shipped, delivered, cancelled

Status change notifications (email/push/in-app)

Creating a draw for any product

Setting conditions: period, number of tickets, ticket price, participation limits

List of active draws

Draw card: product, description, dates, ticket cost, participation progress

Search and filtering by lotteries (by category/status/dates)

Prize description, photos, participation terms

Draw dates and status

Progress: tickets sold / remaining

Participation button: buy ticket(s)

Buying one or several tickets

Limits on the number of tickets per user (if set)

Binding tickets to the account and displaying them in participation history

Payment confirmation and fixing participation in the draw

History of completed draws

Display of winners for each draw

Showing winners on the main page and in lottery history

Prize issuance status for the winner

Fixing the winner selection rules

Determining the winner when the draw ends

Displaying the result in the interface (who won, which draw, when)

Embedding a YouTube Live broadcast on the draw page

Binding a specific broadcast to a specific draw

Public viewing of the broadcast by platform users

Starting the draw at a scheduled time

Publishing the winner after the broadcast ends

Delivery management for purchases: creating a shipment, tracking, receipt confirmation

Logistics statuses and user notifications

Collecting winner data for delivery/issuance

Confirming prize handover and fixing the result in the system

Issuance history and statuses for each prize

Manual product addition, card editing, photo and description management

Unpublishing, availability and category management

Creating and configuring draw conditions: time, mechanics, limits, ticket cost

Control of active and completed draws

Publishing results and displaying winners

Viewing and managing product orders

Managing order statuses and logistics

Receipt confirmation and order completion

Revenue by products

Revenue by lotteries

Platform commission accounting

Period reports and key metrics

Viewing carts

Purchase history and lottery participation

Creating tickets within a draw

A fixed or dynamic number of tickets is created for each draw

Each ticket has a unique identifier

Tickets are bound to a specific draw and a specific product

Each ticket receives a unique number

Duplication is excluded

The number is fixed in the database and assigned to the user after purchase

The user selects the number of tickets

The cost is calculated automatically

After successful payment, tickets are assigned to the user’s account

Ability to set a ticket limit per user

Ability to set a total ticket limit for the draw

Automatic sale closure when the limit is reached

Tickets are distributed in purchase order

When buying several tickets, the user is assigned a number range

Each user sees their ticket list

The interface displays the number of purchased tickets

Ticket-to-user binding is preserved until the draw ends

Ticket sales stop when the limit is reached or by time

The final number of sold tickets is fixed

The system calculates the winning number

The winner is determined automatically based on the ticket number binding to the user

The result is fixed in the system

The winner is displayed on the draw page

The result appears in lottery history

The winner can be shown on the main page

Information is stored about the number of sold tickets

Number ranges

Winning number

History is available for viewing after the draw ends

Protection against re-generation

After the winner is determined, the draw is locked

Retroactive data changes are impossible

Operation logs

Recording the purchase time of each ticket

Logs of winning number formation

Recording all system actions for audit

React

MobX

ASP.NET Core 8.0 — the basis of the server application.

Entity Framework Core 8.0.3 — ORM for working with the database.

Hangfire — a tool for background tasks.

MailKit and MimeKit — for working with email.

MediatR — an implementation of the CQRS pattern for managing requests and commands.

Swashbuckle — for automatic generation of API documentation (OpenAPI/Swagger).

AWS SDK — for integration with Amazon S3 services.

Twilio — for working with WhatsApp.

PostgreSQL — the main database.

Docker — for application containerization.

Serilog — for logging and monitoring.