Hashpop

A decentralized marketplace built on Hedera, enabling peer-to-peer commerce with native wallet integration, on-chain escrow, and end-to-end encrypted messaging.

Platform Overview

Hashpop connects buyers and sellers through a trustless, blockchain-backed trading experience. All transactions settle on-chain via smart contracts deployed to the Hedera network, with HashPack wallet serving as the primary authentication and payment layer.

Key Features

Marketplace

• Fixed-price listings with optional escrow protection
• Offer system allowing buyers to negotiate directly with sellers
• Auction house with timed bidding and reserve prices
• 2% platform fee collected via on-chain treasury contract

Escrow & Settlement

• Smart contract-managed escrow for buyer/seller protection
• Immediate settlement option for trusted transactions
• Shipping confirmation and exchange tracking
• Dispute resolution through contract-level timeouts and refunds

Wallet-to-Wallet Encrypted Messaging

• End-to-end encrypted chat between any two wallets
• X25519 ECDH key exchange with XSalsa20-Poly1305 encryption (TweetNaCl.js)
• Deterministic keypair derivation from wallet signatures — no key storage required
• Backend stores only ciphertext; server never sees plaintext
• Listing-context threads and general-purpose direct messaging

Reputation & Ratings

• On-chain verified purchase history
• Post-sale rating system tied to completed transactions
• Seller reputation scores based on completions, refunds, and timeouts

User Experience

• HashPack wallet authentication (browser extension and mobile deep-link)
• Real-time dashboard with purchase history, active listings, and analytics
• Wishlist tracking for listings and auctions
• Media-rich listings with image and video uploads
• Responsive design optimized for desktop and mobile

Architecture

Layer	Technology
Frontend	Next.js 14, React 18, TailwindCSS
Backend	Express, Prisma ORM, PostgreSQL
Blockchain	Hedera (Hashgraph), Solidity smart contracts
Wallet	HashPack via HashConnect / WalletConnect
Encryption	TweetNaCl.js (X25519 + XSalsa20-Poly1305)
Contracts	Marketplace, Escrow, Treasury (Hardhat)
Indexer	Hedera Mirror Node event sync

AuctionHouse.sol stays in the repo for the already-deployed contract. New deploys do not include it.

Project Structure

frontend/    Next.js application
backend/     Express API server, Prisma schema, event indexer
contracts/   Solidity smart contracts (Hardhat)

Deployment

See DEPLOY.md for production deployment instructions.

License

Proprietary. All rights reserved.