Add NFT marketplace aggregator with real-time floor price tracking

[thewealthyplace]

Summary

Build a marketplace aggregator view inside nftguild that consolidates listings, floor prices, and volume data from all major Stacks NFT marketplaces (Gamma, Byzantion, etc.) into a single dashboard per collection.

Problem

NFT creators and collectors currently have to manually check multiple marketplaces to understand the true floor price, best listing, and trading volume for a collection. This fragmented experience hurts price discovery and makes it hard for guild creators to track their collection's performance.

Proposed Solution

Aggregator Dashboard (per collection)

Collection: Pixel Prophets Genesis (5,555 items)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Global Floor:   42 STX  (Gamma)
24h Volume:     1,840 STX across 3 marketplaces
7d Volume:      12,300 STX
Total Sales:    2,103 / 5,555 (37.9% traded)
Unique Holders: 1,847

Listings by Marketplace:
  Gamma       │ 312 listed │ Floor: 42 STX
  Byzantion   │  87 listed │ Floor: 44 STX
  Other       │  23 listed │ Floor: 46 STX

Recent Sales:
  #4821  42 STX  Gamma     2 min ago
  #0093  55 STX  Byzantion 11 min ago
  #2204  42 STX  Gamma     23 min ago

Data Sources

Marketplace	Method	Update Frequency
Gamma	Public API + on-chain events	Every block
Byzantion	On-chain event indexing	Every block
Others	On-chain STX transfer events	Every block

Indexer Architecture

// Subscribe to marketplace contract events via Hiro API WebSocket
const socket = connectWebSocket(HIRO_WS_URL);

socket.subscribe({
  type: 'contract_event',
  contract_id: GAMMA_CONTRACT_ADDRESS,
  event: 'nft-sold'
}, (event) => {
  db.upsertSale({
    tokenId: event.token_id,
    price: event.price,
    marketplace: 'gamma',
    buyer: event.buyer,
    seller: event.seller,
    blockHeight: event.block_height
  });
});

Rarity + Listing Integration

• Each listing enriched with rarity rank from the trait generator
• Price / Rarity Rank score to surface undervalued NFTs
• Filter and sort: by price, rarity, recent sales, marketplace

Alerts

• Guild admins can set floor price alerts (notify if floor drops below X STX)
• Whale sale alerts (notify on any sale > Y STX)
• Delivered via email or webhook

Acceptance Criteria

• Floor price aggregated correctly across all indexed marketplaces
• 24h and 7d volume computed accurately
• Recent sales feed updates within 1 block (~10 seconds)
• Rarity rank displayed alongside each listing
• Floor price alert system (email + webhook)
• Historical floor price chart (30 days)
• API endpoint: GET /api/v1/collections/:contract/market
• Mobile responsive layout

References

• Gamma.io
• Byzantion
• Hiro Platform API - NFT events