KickAlert — Nike Product Alert SaaS

Get notified the moment your favourite Nike products go on sale or restock.

Motivation

Sneaker drops and Nike sales sell out in minutes. Manually refreshing product pages is tedious and unreliable. KickAlert was built to automate that — scraping Nike every 5 minutes and sending an email the moment a price drops or a sold-out product comes back in stock, so you never miss a drop again.

Quick Start

Prerequisites: Go 1.22+, Node.js 20+, PostgreSQL, an Apify account (for the Nike scraper actor), and an SMTP server.

# 1. Clone the repo
git clone https://github.com/your-username/kick-alert.git
cd kick-alert

# 2. Copy the example env file and fill in your values
cp .env.example .env

# 3. Run database migrations
make db/migrations/up

# 4. Start the API (background scheduler included)
make run/api

The API will be available at http://localhost:4000.

Usage

Register and activate an account

# Register
curl -X POST http://localhost:4000/v1/register \
  -H "Content-Type: application/json" \
  -d '{"name":"Jane Doe","email":"jane@example.com","password":"pa$$word123"}'

# Activate (token is sent to your email)
curl -X PUT http://localhost:4000/v1/activation \
  -H "Content-Type: application/json" \
  -d '{"token":"<activation_token>"}'

Log in and watch a product

# Log in — returns access token in JSON, sets refresh_token as an httpOnly cookie
curl -X POST http://localhost:4000/v1/login \
  -H "Content-Type: application/json" \
  -c cookies.txt \
  -d '{"email":"jane@example.com","password":"pa$$word123"}'

# Add a Nike product to the catalog by URL
curl -X POST http://localhost:4000/v1/products \
  -H "Authorization: Bearer <access_token>" \
  -H "Content-Type: application/json" \
  -d '{"product_url":"https://www.nike.com/t/air-max-90-shoes/..."}'

# Add the product to your watchlist
curl -X POST http://localhost:4000/v1/watchlist \
  -H "Authorization: Bearer <access_token>" \
  -H "Content-Type: application/json" \
  -d '{"product_id":"<product_uuid>","alert_sale":true,"alert_restock":true}'

From here the background scheduler takes over — you will receive an email whenever a price drop or restock is detected.

Overview

KickAlert is a SaaS that monitors Nike for price drops and restocks — then notifies subscribed users via email. Supports footwear, apparel, and equipment.

Core user flow:

User signs up and activates their account via email
User submits a Nike product URL; the API scrapes it via Apify and adds it to the catalog
User adds the product to their watchlist with optional alert preferences
A background scheduler re-scrapes every 5 minutes
When a price drop or restock is detected, an email notification is dispatched and logged

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        FRONTEND                                  │
│               React Router v7 + Vite (SPA, no SSR)              │
│        Auth · Dashboard · Watchlist · Notification Feed          │
└──────────────────────────┬──────────────────────────────────────┘
                           │ HTTPS / REST
┌──────────────────────────▼──────────────────────────────────────┐
│                      API SERVICE (Go)                            │
│         /auth  /products  /watchlist  /notifications             │
│                     JWT · Rate Limiting                          │
│                                                                  │
│  ┌─────────────────────────────────────────────────────────┐    │
│  │              Background Goroutines (same process)        │    │
│  │                                                          │    │
│  │   robfig/cron → Scheduler → Apify Scraper → Notifier    │    │
│  └─────────────────────────────────────────────────────────┘    │
└──────────────────────────┬──────────────────────────────────────┘
                           │ reads / writes
                           ▼
              ┌────────────────────────┐
              │       PostgreSQL        │
              │                        │
              │  users                 │
              │  tokens                │
              │  products              │
              │  watchlist             │
              │  price_history         │
              │  notifications         │
              └────────────────────────┘

Everything runs in a single Go binary. The scheduler, scraper, and notifier are background goroutines — no message broker needed.

How the Scraper Works

The scraper runs as a goroutine launched on app startup using robfig/cron.

Every 5 minutes:
  1. Query DB for all products
  2. For each product: call Apify Nike actor using the product's external_id
  3. Compare fetched price/stock against current DB row
  4. If price changed:
     a. Insert row into price_history
     b. Update products.current_price, in_stock, last_scraped_at
     c. Query watchlist for users watching this product
     d. Filter by user alert preferences (alert_sale, alert_restock)
     e. Send email notification via SMTP
     f. Insert row into notifications table

Scrape interval: every 5 minutes for all tiers. Tier differences are enforced at the watchlist level.

Database Schema

-- Core users
CREATE TABLE users (
  id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  email           citext UNIQUE NOT NULL,
  password_hash   TEXT NOT NULL,
  name            TEXT,
  activated       BOOLEAN DEFAULT false,
  notify_email    BOOLEAN DEFAULT true,
  notify_push     BOOLEAN DEFAULT false,
  tier            TEXT DEFAULT 'free',   -- 'free' | 'pro'
  created_at      TIMESTAMPTZ DEFAULT now(),
  updated_at      TIMESTAMPTZ DEFAULT now()
);

-- Auth tokens (activation + refresh)
CREATE TABLE tokens (
  hash       TEXT PRIMARY KEY,
  user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  expiry     TIMESTAMPTZ NOT NULL,
  scope      TEXT NOT NULL   -- 'activation' | 'refresh'
);

-- Normalised Nike product catalog (shared across all users)
CREATE TABLE products (
  id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  slug            TEXT UNIQUE NOT NULL,
  name            TEXT NOT NULL,
  sku             TEXT NOT NULL,
  external_id     TEXT UNIQUE NOT NULL,   -- Nike cloudProductId
  category        TEXT NOT NULL DEFAULT 'FOOTWEAR',
  url             TEXT NOT NULL,
  image_url       TEXT,
  current_price   TEXT,
  currency        TEXT DEFAULT 'USD',
  in_stock        BOOLEAN,
  last_scraped_at TIMESTAMPTZ,
  created_at      TIMESTAMPTZ DEFAULT now()
);

-- User watch preferences per product
CREATE TABLE watchlist (
  id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id       UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  product_id    UUID NOT NULL REFERENCES products(id) ON DELETE CASCADE,
  alert_sale    BOOLEAN DEFAULT true,
  alert_restock BOOLEAN DEFAULT true,
  created_at    TIMESTAMPTZ DEFAULT now(),
  UNIQUE(user_id, product_id)
);

-- Full price + stock history (append-only)
CREATE TABLE price_history (
  id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  product_id UUID NOT NULL REFERENCES products(id) ON DELETE CASCADE,
  price      TEXT,
  in_stock   BOOLEAN,
  scraped_at TIMESTAMPTZ DEFAULT now()
);

-- Sent notifications log
CREATE TABLE notifications (
  id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id      UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  product_id   UUID NOT NULL REFERENCES products(id) ON DELETE CASCADE,
  watchlist_id UUID NOT NULL REFERENCES watchlist(id) ON DELETE CASCADE,
  type         notification_type NOT NULL,   -- 'PRICE_DROP' | 'RESTOCK'
  old_price    TEXT,
  new_price    TEXT,
  read         BOOLEAN DEFAULT false,
  created_at   TIMESTAMPTZ DEFAULT now()
);

Project Structure

kick-alert/
├── cmd/api/
│   ├── main.go            # Entry point, config loading, starts server
│   ├── server.go          # HTTP server with graceful shutdown
│   ├── routes.go          # Gin router and middleware setup
│   ├── middleware.go       # JWT auth, CORS, per-IP rate limiting
│   ├── errors.go          # Unified error response helpers
│   ├── healthcheck.go     # GET /v1/healthcheck
│   ├── auth.go            # Login, token refresh, logout, activation handlers
│   ├── users.go           # Register handler
│   ├── products.go        # Product catalog handlers + Apify scrape on add
│   ├── watchlist.go       # Watchlist CRUD handlers
│   ├── notifications.go   # Notification retrieval + read handlers
│   ├── scheduler.go       # Background scraper + notifier goroutine
│   └── apify.go           # Apify Nike actor client
├── internal/
│   ├── auth/
│   │   └── auth.go        # JWT creation/validation, Argon2id hashing, token generation
│   ├── database/          # sqlc-generated type-safe query code
│   │   ├── db.go
│   │   ├── models.go
│   │   ├── users.sql.go
│   │   ├── tokens.sql.go
│   │   ├── products.sql.go
│   │   ├── watchlist.sql.go
│   │   ├── notifications.sql.go
│   │   └── price_history.sql.go
│   └── mailer/
│       ├── mailer.go      # SMTP email client with retry logic
│       └── templates/
│           ├── user_welcome.tmpl
│           └── price_alert.tmpl
├── frontend/
│   ├── app/
│   │   ├── routes/        # File-based routes (React Router v7)
│   │   │   ├── home.tsx                        # Landing page
│   │   │   ├── _auth.tsx                       # Auth layout (login/register/activate)
│   │   │   ├── _auth.login.tsx
│   │   │   ├── _auth.register.tsx
│   │   │   ├── _auth.activate.tsx
│   │   │   ├── _protected.tsx                  # Protected layout (requires auth)
│   │   │   ├── _protected.dashboard.tsx        # Watchlist dashboard
│   │   │   ├── _protected.notifications.tsx
│   │   │   ├── _protected.products.$id.tsx     # Product detail + price chart
│   │   │   └── _protected.settings.tsx
│   │   ├── components/
│   │   │   ├── dashboard/  # Dashboard-specific components
│   │   │   └── ui/         # shadcn/ui component library
│   │   ├── context/
│   │   │   └── auth.tsx    # Auth context + token state
│   │   ├── hooks/          # Custom React hooks
│   │   └── lib/
│   │       ├── api.ts      # Axios instance with auth interceptors
│   │       ├── auth.ts     # Token helpers
│   │       └── schema.ts   # Zod validation schemas
│   ├── Dockerfile
│   ├── react-router.config.ts
│   ├── vite.config.ts
│   └── package.json
├── sql/
│   ├── schema/            # goose migrations (6 files)
│   └── queries/           # sqlc source queries
├── sqlc.yaml
├── Makefile
└── .env

Tech Stack

Layer	Choice	Reason
Language	Go	Cheap goroutines, great for background workers
Frontend	React Router v7 + Vite	SPA mode, file-based routing, fast HMR
UI Components	shadcn/ui (Radix UI + Tailwind v4)	Accessible, unstyled primitives with Tailwind
Data Fetching	TanStack Query	Caching, background refetch, loading states
Forms	React Hook Form + Zod	Performant forms with schema validation
Charts	Recharts	Composable charts for price history
HTTP Client	Axios	Interceptors for auth token injection
Database	PostgreSQL	Relational integrity, battle-tested
DB Queries	sqlc	Type-safe SQL, no ORM magic
Migrations	goose	File-based, CI-friendly
HTTP Router	Gin	Lightweight, composable middleware
Job Scheduling	robfig/cron	Battle-tested Go cron library
Email	go-mail + SMTP	Standard SMTP, works with any provider
Scraping	Apify	Managed Nike scraper actor
Auth	JWT + Argon2id	Stateless access tokens + secure password hashing
Config	env vars + godotenv	12-factor app compliant

Freemium Tier Design

Feature	Free	Pro
Watchlist slots	5 products	Unlimited
Scrape frequency	Every 5 min	Every 5 min
Alert channels	Email	Email
Price history	Full	Full
Notification preferences	—	Toggle email alerts on/off

API Reference

All authenticated endpoints require Authorization: Bearer <access_token>.

Auth

POST  /v1/register          Create a new account
                            Body: { name, email, password }

POST  /v1/login             Authenticate and get access token
                            Body: { email, password }
                            Response: { user, token }
                            Cookie set: refresh_token (httpOnly)

GET   /v1/refresh           Rotate tokens using the refresh_token cookie
                            No body or header needed — browser sends cookie automatically
                            Response: { access_token }
                            Cookie set: refresh_token (rotated, httpOnly)

POST  /v1/logout            Clear the refresh token cookie
                            Response: 204 No Content

PUT   /v1/activation        Activate account
                            Body: { token }

Products (authenticated)

POST  /v1/products                      Scrape and add a product by Nike URL
                                        Body: { product_url }
                                        Response: 202 Accepted (scraping is async)

GET   /v1/products                      Search catalog
                                        Query: ?q=&category=&in_stock=&min_price=&max_price=&page=&limit=

GET   /v1/products/:id                  Get product details

GET   /v1/products/:id/price-history    Get price + stock history
                                        Query: ?limit= (default: 50, max: 200)

Watchlist (authenticated)

POST   /v1/watchlist        Add a product to watchlist
                            Body: { product_id, alert_sale, alert_restock }

GET    /v1/watchlist        Get all watched products with current price/stock

PATCH  /v1/watchlist/:id    Update alert preferences
                            Body: { alert_sale, alert_restock }

DELETE /v1/watchlist/:id    Remove from watchlist

Notifications (authenticated)

GET    /v1/notifications            Get notification history
                                    Query: ?page=&page_size=&unread=true

PATCH  /v1/notifications/:id/read   Mark a notification as read

PATCH  /v1/notifications/read-all   Mark all notifications as read

User Preferences (authenticated, pro only)

PATCH  /v1/users/me/notifications   Toggle email notifications
                                    Body: { notify_email: true | false }
                                    Returns 403 for free-tier users

Healthcheck

GET   /v1/healthcheck       Returns status, environment, and version

Environment Variables

Variable	Required	Description
`PORT`	Yes	Server port (e.g. `4000`)
`ENV`	Yes	`development` or `production` — controls cookie `Secure` flag
`KICK_ALERT_DB_DSN`	Yes	PostgreSQL connection string
`DB_MAX_OPEN_CONNS`	Yes	Max open DB connections
`DB_MAX_IDLE_CONNS`	Yes	Max idle DB connections
`DB_MAX_IDLE_TIME`	Yes	Connection idle timeout in minutes
`JWT_SECRET`	Yes	Secret key for signing JWTs
`FRONTEND_ACTIVATION_URL`	Yes	Base URL for activation email link (e.g. `http://localhost:3000/activate`)
`ALLOWED_ORIGINS`	Yes	Comma-separated list of allowed CORS origins (e.g. `http://localhost:3000,https://kickalert.com`)
`SMTP_HOST`	Yes	SMTP server hostname
`SMTP_PORT`	Yes	SMTP server port
`SMTP_USERNAME`	Yes	SMTP username
`SMTP_PASSWORD`	Yes	SMTP password
`SMTP_SENDER`	Yes	Sender address (e.g. `KickAlert <no-reply@example.com>`)
`APIFY_TOKEN`	Yes	Apify API token for the Nike scraper actor
`LIMITER_ENABLED`	No	Enable rate limiting (default: `false`)
`LIMITER_RPS`	No	Requests per second per IP (default: `2`)
`LIMITER_BURST`	No	Burst size (default: `4`)

Local Development

# Run migrations
make db/migrations/up

# Start API (includes background scheduler)
make run/api

# Start frontend dev server (in a separate terminal)
make install/deps # The frist time run this command
make run/frontend

The frontend dev server runs at http://localhost:5173.

Build Phases

Phase 1 — MVP

Phase 3 — Growth & Monetisation

Stripe integration (free → pro upgrade)
Webhook delivery (Discord, Telegram, custom URL)

Name		Name	Last commit message	Last commit date
Latest commit History 9 Commits
bin		bin
cmd/api		cmd/api
frontend		frontend
internal		internal
sql		sql
vendor		vendor
.gitignore		.gitignore
Makefile		Makefile
README.md		README.md
go.mod		go.mod
go.sum		go.sum
sqlc.yaml		sqlc.yaml
steps.md		steps.md

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Repository files navigation

KickAlert — Nike Product Alert SaaS

Table of Contents

Motivation

Quick Start

Usage

Register and activate an account

Log in and watch a product

Overview

Architecture

How the Scraper Works

Database Schema

Project Structure

Tech Stack

Freemium Tier Design

API Reference

Auth

Products (authenticated)

Watchlist (authenticated)

Notifications (authenticated)

User Preferences (authenticated, pro only)

Healthcheck

Environment Variables

Local Development

Build Phases

Phase 1 — MVP

Phase 3 — Growth & Monetisation

About

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Releases

Packages

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Contributors

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Repository files navigation

KickAlert — Nike Product Alert SaaS

Table of Contents

Motivation

Quick Start

Usage

Register and activate an account

Log in and watch a product

Overview

Architecture

How the Scraper Works

Database Schema

Project Structure

Tech Stack

Freemium Tier Design

API Reference

Auth

Products (authenticated)

Watchlist (authenticated)

Notifications (authenticated)

User Preferences (authenticated, pro only)

Healthcheck

Environment Variables

Local Development

Build Phases

Phase 1 — MVP

Phase 3 — Growth & Monetisation

About

Resources

Uh oh!

Stars

Watchers

Forks

Releases

Packages 0

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