Flash Sale by time slot
Sessions underway and sessions coming up, a countdown that restarts on its own every day, and sale prices that switch on and off at the scheduled time.
E-commerce · Custom code Seoul Crush
Seoul Crush distributes genuine Korean cosmetics and beauty devices. 123Website built the whole system custom in Next.js: code hunting, flash sales, auto-confirmed QR payment, a multi-role admin, and room to grow into a multi-seller marketplace.
- Industry
- Cosmetics and beauty devices
- Website type
- E-commerce, install like an app
- Platform
- Next.js 16 + Fastify, custom code
- Implementation
- June 2026 to date
- 95interface screens
- 6user roles
- 3portals: customer, admin, seller
- 7policies required under e-commerce rules
Clients
Who Seoul Crush is
Seoul Crush Co., Ltd. brings genuine Korean cosmetics and beauty devices to people in Vietnam, from skincare and makeup to at-home skincare devices. The brand wanted a proper K-Beauty shop of its own, rather than selling only on marketplaces.
- Head office27C Quoc Huong, An Khanh Ward, HCMC
- ProductsCosmetics, aesthetic devices, hair and body care
- Distributed brandsSkeyndor, Agnes, Laseroptek, Sciton, ViOL, Shurink
- BuyersShoppers across the country who love K-Beauty
The problem
A store website has to work like a marketplace
Cosmetics shoppers are used to hunting codes, waiting for flash sales and paying in a few taps on the big marketplaces. A brand's own site only keeps them if it offers a comparable experience, plus the trust of genuine products.
Looks like Shopify, converts like Shopee.
Design direction locked in from the first working session
-
01
Marketplace-style promotions
Discount codes, free-shipping codes, shop codes, timed flash sales and a voucher wallet: things cosmetics shoppers already use.
-
02
Payment that does not wait for manual reconciliation
The customer scans a QR code to transfer, and the order moves to paid on its own. COD stays available for shoppers who prefer to pay on delivery.
-
03
In line with e-commerce rules
The required policies in place, clear company details, and single-store mode for registration with the Ministry of Industry and Trade.
-
04
Several people running it together
Accounting, marketing and content each have their own permissions. Sellers can be added later without rebuilding the system.
Customer experience
A 5-step purchase path, built for mobile first
More than half the design time went to the phone screens: an app-style bottom tab bar, a fixed buy button, and discount codes saved in one tap.
-
Step 1
Discovery
Campaign banners, a Discount codes shortcut, Flash Sale and categories with photos.
-
Step 2
Hunt flash sales
Time slots that are on now and coming up, with a countdown at the top of the page.
-
Step 3
Save a code to the wallet
Flash Coupon shows how many are left, saves in one tap, and can be applied at checkout.
-
Step 4
Filter products
Mall and Freeship badges, and filters by category, brand and price range.
-
Step 5
Shop now
The flash-sale price sits on the photo, and the Chat, Add to cart and Buy now bar stays on screen.
Features
What Seoul Crush does for shoppers
Every feature below was built for this website, not taken from an off-the-shelf plugin.
Voucher wallet, stack codes
Three code types: discount, free shipping and shop code. Each order can use at most one code of each type, and the system calculates the rest.
Cart by shop, pick a code in the cart
The cart is saved to the account, so it is not lost when you change devices. The 3-step progress, Cart, Checkout, Complete, stays visible.
Automatically verified QR payments
The customer scans a dynamic VietQR code via SePay. Once the money is in the account, the order changes status on its own. The webhook carries a security signature and stops the same transaction being recorded twice. Payments where the amount does not match go into a reconciliation queue for accounting.
- Scan VietQR
- Funds received
- Paid order
SePay QRCOD, can be turned off per productReconciliation in the admin
Secure sign-in
A 6-digit OTP by email, and sign-in with Google.
New two-level addresses
Province and ward/commune under the 2025 administrative reorganization.
Install like an app
Add to the home screen, with separate instructions for iPhone.
Hoa Seoul reward points
Earn points on an order, then use them as money off the next one.
7-day returns
The customer submits a request and tracks the refund inside their account.
Reviews with photos
Reviews are approved before they show, and photos open larger.
Automated email
Order confirmed, paid, out for delivery, completed, refunded.
Smart search
Keyword suggestions, search history and trending searches.
Admin system
One dashboard, a permission set for each person
A custom admin built for how Seoul Crush works: the menu shows and hides by role, and every staff action is logged.
- Super adminFull access, manage staff, and view the action log.
- AccountingOrders, finance, SePay reconciliation and seller payouts.
- MarketingVouchers, promo popups, reward points and Seoul Live.
- ContentProducts, categories, reviews, homepage, blog.
- Sellers (when the marketplace is on)Products, sub-orders, returns, revenue and shop decoration.
- ClientsOrders, voucher wallet, reward points, wishlist and returns.
- Variations, cost price, sale schedule
- Stock alerts, stock history
- Split orders by seller
- Create a manual order, print the invoice
- Bulk actions
- Customer 360°
- Media library
- Sitemap and robots in the admin
- Action log
Technology
Layered architecture, ready to grow
The interface, API and data sit apart in one shared codebase. A new sales channel, a new seller or an app later can all reuse the core.
- UserBrowser, install like an app (PWA)
- InterfaceNext.js 16 · React 19
- APIFastify 5 · Swagger
- DataPostgreSQL 16 · Prisma 6
- SePay webhookAutomatic payment confirmation, signed
- Email via a queueRetry on failure, so no message is lost
- Push notificationsSession reminders and alerts for followers
- SecurityHashed passwords, hashed OTPs, an action log
InfrastructureDocker ComposeNginxSSL Let’s EncryptGitHub ActionsBuild images on GHCRA dedicated VPS
Shopify-style technical SEO
Sitemaps split by type (products, categories, pages, posts), robots and metadata generated automatically, Product structured data for each product, configured in the admin.
Tests for the amount calculation
An automated test suite for vouchers, prices, shipping fees and returns: it runs again on every code change so the cart and the order do not disagree on the amount.
How 123Website built it
From the design to live operations, stage by stage
Each stage ends with a working build for Seoul Crush to try and comment on, instead of waiting until the end to see it.
- 06/2026
System core
Figma design, a shared codebase, the admin, SePay payment and the voucher rules.
- 07/2026
Ready to run
Automated email, a blog, stock management, single-store mode under the Ministry of Industry and Trade, and the domain connected. Handover with an admin guide and an acceptance script.
- 08 – 09/2026
Conversion optimization
Reward points, a voucher wallet, install like an app, email OTP, a shipping fee per shop, and all 7 required policies.
- 10/2026
New interface
Rebuild the subpages from the October 2026 Figma, and start the Seoul Live livestream phase.
- Design first, code afterEvery screen is locked in Figma, with desktop and phone versions, before development.
- Two teams working in parallelOne team builds the platform and the admin, another builds the shopper interface, and they meet at a shared API.
- Acceptance against a scriptHandover includes an admin guide and a test script for each function, so the client can check them.
The live site
Your website on desktop and mobile
Screenshots from seoulcrush.vn on 16 October 2026.
- Product detailsFlash-sale price, Mall and Freeship+ badges, and the policies right under the buy button.
- Lists and filtersFilter by category, brand and price range; sort by popular, most sold and price.
- Description in tabsDescription, ingredients, how to use, reviews and related products.
- 3-step cartGrouped by shop, a code field, a button to open the voucher wallet, and a fixed order summary.
- Home
- Flash Coupon
- Product details
- Flash Sale
Next phase · In progress
Seoul Live: shop by livestream on the website
Not dependent on a social platform: customers watch the livestream, grab a deal and pay without leaving seoulcrush.vn.
- Go live from a phone or from OBS, on a dedicated streaming server
- Pin a product, live prices, deals grabbed by slot, and no overselling
- Buy and pay inside the live frame; the player shrinks while you browse
- Session reminders by push notification, and recordings to watch later
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- Hotline 0932 092 002
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