Skin Sniper — Backend API

A lightweight Node.js server that fetches and compares skin prices across Skinport, Steam Market, and CSFloat, then serves deals to the dashboard.

Skin Sniper

A personal CS2 skin arbitrage tool that scans Skinport and CSFloat for underpriced listings, compares them against market value, and automatically relists purchased items on CSFloat for profit.

Features

• Live deal scanner — scans Skinport (12,000+ items) and CSFloat for listings below market price
• Steam buys tab — finds skins cheaper on Steam Market than their CSFloat resell value
• Buy & Relist flow — click to open the purchase page, server watches for the item to arrive and auto-lists it on CSFloat
• Profit calculator — accounts for Skinport (12%), CSFloat (2%), and Steam (15%) fees
• Auto-refresh — set a scan interval and leave it running
• Local dashboard — simple HTML file, no hosting needed

Stack

• Backend — Node.js + Express
• Data sources — Skinport API, CSFloat API, Steam Market API, ByMykel CSGO-API
• Dashboard — vanilla HTML/CSS/JS, opens as a local file

Setup

Requirements: Node.js 18+

# 1. Install dependencies
npm install

# 2. Start the server (auto-restarts on file changes)
npm run dev

# Or just run it
npm start

The API runs on http://localhost:3001 by default.

---

Endpoints

GET /health

Simple health check.

{ "ok": true, "time": "2026-03-22T12:00:00.000Z" }

GET /deals

Returns a list of snipe opportunities sorted by discount.

Query parameters:

Param	Default	Description
game	cs2	cs2, dota2, or tf2
minPrice	0.05	Minimum listing price in USD
maxPrice	50	Maximum listing price in USD
minDiscount	15	Minimum % below market price
source	all	all, skinport, steam, or csfloat

Example:

GET http://localhost:3001/deals?game=cs2&minPrice=1&maxPrice=20&minDiscount=20

Response:

{
  "deals": [
    {
      "name": "AK-47 | Redline (Field-Tested)",
      "game": "cs2",
      "source": "skinport",
      "listing": 4.20,
      "market": 6.10,
      "discount": 31.1,
      "profit": 1.17,
      "url": "https://skinport.com/item/ak-47-redline-field-tested"
    }
  ],
  "scannedAt": "2026-03-22T12:00:00.000Z",
  "count": 1
}

---

Connecting to the dashboard

In the dashboard widget, change the API_BASE constant at the top of the script block from "" (mock mode) to "http://localhost:3001".

The dashboard's "Scan now" button will then call the real API.

---

Rate limits & caching

• Steam is throttled to 1 request per 3.5 seconds (their limit is ~1/3s). A scan checks up to 8 Steam items per game to stay safe.
• Skinport sales history is cached for 5 minutes (their recommended TTL).
• CSFloat listings are cached for 5 minutes.

If you're hitting rate limits, increase RATE_LIMIT_MS in server.js.

---

Expanding the item list

The server uses a SEED_ITEMS list in server.js as starting points for price lookups. To add more items, just append to the relevant array:

const SEED_ITEMS = {
  cs2: [
    "AK-47 | Redline (Field-Tested)",
    "Your New Item Here",   // <-- add any Steam market_hash_name
    ...
  ],
  ...
};

You can find the exact market_hash_name for any item on the Steam Community Market URL — it's the name after /listings/730/.

---

Next steps

• Add a SQLite database to track price history over time
• Add desktop notifications (via node-notifier) when a hot deal appears
• Scrape a full item list from a community source like CSGO Stash
• Add Buff163 as a fourth price source =======

1. Clone or download the repo

cd Skin-Sniper

2. Install dependencies

npm install

3. Configure your API keys (see below)

4. Start the server

npm run dev

Open `dashboard.html` in your browser. The server runs on `http://localhost:3001`.

## Configuration

Create a `.env` file in the project root:

```env
STEAM_API_KEY=your_steam_api_key
STEAM_ID=your_64bit_steam_id
CSFLOAT_KEY=your_csfloat_api_key
PORT=3001

Getting your keys:

Key	Where to get it
STEAM_API_KEY	https://steamcommunity.com/dev/apikey
STEAM_ID	https://steamid.io — paste your profile URL, copy the steamID64 value
CSFLOAT_KEY	https://csfloat.com — Profile → Settings → API

How it works

Deals tab

Fetches all Skinport listings and compares min_price against suggested_price. Also pulls CSFloat buy-now listings and compares against their reference price. Items where the listing price is below market by your chosen threshold show up as deals.

Steam buys tab

Randomly samples weapon skins from the full CS2 item list, checks their Steam Market price, and compares against Skinport's suggested price as the resell reference. Useful for catching underpriced Steam listings.

Buy & Relist

1. Click Buy & Relist on any deal
2. Purchase page opens in a new tab — complete the purchase manually
3. Server polls CSFloat's trades API every 30 seconds
4. When the trade completes, the item is automatically listed on CSFloat at just under market price

Profit calculation

Platform	Fee	Formula
Skinport	12%	market × 0.88 - listing
CSFloat	2%	market × 0.98 - listing
Steam → CSFloat	15% buy-side baked in	sellRef × 0.98 - steamPrice

File structure

Skin-Sniper/
├── server.js        # Express API server
├── dashboard.html   # Local frontend dashboard
├── package.json
├── .env             # Your API keys (never commit this)
└── .gitignore

API endpoints

Endpoint	Description
GET /health	Server health check
GET /deals	Skinport + CSFloat deals
GET /steam-deals	Steam Market arbitrage opportunities
POST /buy	Register a purchase for inventory watching
GET /inventory	Pending and listed items
DELETE /listing/:id	Cancel a CSFloat listing

Deal filters

Param	Default	Description
game	cs2	cs2, dota2, tf2
minPrice	0.05	Minimum listing price
maxPrice	1000	Maximum listing price
minDiscount	15	Minimum % below market
source	all	all, skinport, csfloat

Rate limits & caching

Source	Cache TTL	Notes
Skinport	15 minutes	Bulk fetch of all items at once
CSFloat	5 minutes	50 listings per scan
Steam	10 minutes per item	Rate limited to 1 req/3.5s
ByMykel item list	24 hours	20,000+ CS2 skin names

Notes

• Steam buying opportunities are rare — Steam prices typically run higher than third-party sites due to the built-in 15% fee. The scanner catches occasional underpriced listings.
• Skinport's API rate limits to ~4 requests per minute. The 15-minute cache prevents 429 errors during normal use.
• Auto-relisting requires a completed CSFloat trade — items bought on Steam must be registered manually via the Buy & Relist button.
• Always verify deals manually before purchasing. Steam's price API can return stale or incorrect data for items with multiple variants (e.g. Doppler phases).

Disclaimer

This tool is for personal use. Always comply with the terms of service of Steam, Skinport, and CSFloat. Automated purchasing is not supported — all buys require manual confirmation.

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