External NFT Repositories

These repositories live outside the turbo monorepo. They were the attempt to move EmProps from a single monolithic contract (all collections in one contract) to a contract factory approach (one contract per collection). The scope ballooned and none of this work shipped to production.

The new Diamond/Arbitrum build solves the same problem — factory-deployed per-collection contracts — but scoped to a real use case first. Once battle-tested, it becomes what these repos were trying to be.

Repository Summary

Repository	Location	Stack	Completeness	Role in New Architecture
emprops-hardhat	`~/code/emprops/nft_investigation/emprops-hardhat`	Hardhat 2, Solidity 0.8.24, ERC721A	~70%	Reference only — Diamond replaces ERC1167 proxies
emprops-ponder	`~/code/emprops/nft_investigation/emprops-ponder`	Ponder 0.9.17, Drizzle, PostgreSQL	~60%	Phase 6 — Add when secondary market needed
emprops-react-web3	`~/code/emprops/nft_investigation/emprops-react-web3`	React 18, Wagmi 2, RainbowKit 2	~50%	Reference — Patterns inform studio hooks
emprops-api (Java)	`~/code/emprops/core-services/emprops-api`	Java, Spring Boot, Gradle	Legacy	Feature spec — Documents marketplace capabilities
emprops-open-api	`~/code/emprops/emprops-open-api`	Node.js	Legacy	Reference — Metadata patterns

1. emprops-hardhat (Smart Contracts)

Path: /Users/the_dusky/code/emprops/nft_investigation/emprops-hardhatStack: Hardhat 2.22.19, Solidity 0.8.24, OpenZeppelin 5.0.2, ERC721A 4.3.0, Viem 2.23.5

Contracts

Contract	LOC	Description
OwnerTokenContract	176	UUPS upgradeable ERC721A for collection ownership tokens. Two-step minting: mint token, then assign controlled contract. Maps tokenId → contract address.
NFTContractFactoryContract	272	UUPS factory using ERC1167 Clones (minimal proxies). Deterministic CREATE2 deployment. Two modes: immediate and lazy. Registers implementations and initializers.
SimpleAppContract	303	Individual ERC721A NFT collection (minimal proxy). Owner-token-gated admin, configurable maxSupply/mintPrice/maxPerMint. Pausable, reentrancy protection, direct withdrawal.
SimpleAppInitializerContract	65	Initialization logic for SimpleApp parameters (maxSupply, mintPrice, maxPerMint, startDateTime). Factory-only access.
Interfaces	—	IEmPropsApp, IAppInitializer, IOwnerToken, ISimpleApp, IEvents

Architecture Pattern

User creates collection
  → NFTContractFactory.createNFTContract()
    → Factory mints OwnerToken to user (ownership NFT)
    → Factory deploys SimpleApp (ERC1167 minimal proxy, CREATE2)
    → SimpleAppInitializer configures parameters
    → Collection live, user holds OwnerToken

Database Integration

Deployments stored in PostgreSQL (contract_deployments table) for cross-package coordination. Ponder reads contract addresses from this table.

Relevance to Diamond Architecture

emprops-hardhat Concept	Diamond Equivalent
OwnerToken (ownership NFT)	OwnershipFacet (simpler, no separate NFT needed)
NFTContractFactory (ERC1167 clones)	DiamondFactory (deploys Diamond proxies)
SimpleAppContract (ERC721A)	ERC721AFacet + MintFacet + MetadataFacet
SimpleAppInitializer	Diamond constructor init via `diamondCut`
CREATE2 deterministic addresses	CREATE2 in DiamondFactory

Bottom line: The ERC721A base logic from SimpleAppContract is highly reusable as Diamond facet code. The factory pattern is conceptually the same but uses Diamond proxies instead of ERC1167 minimal proxies.

Full Documentation

See emprops-hardhat Documentation for complete contract details, deployment pipeline, database schema, and migration notes.

2. emprops-ponder (Blockchain Indexer)

Path: /Users/the_dusky/code/emprops/nft_investigation/emprops-ponderStack: Ponder 0.9.17, Drizzle ORM 0.39.3, PostgreSQL, Socket.io 4.7.4, Viem 2.21.3

Schema (8 tables)

Table	Description
ownerTokens	Owner token records
ownerTokenTransfers	Owner token transfer history
contractUpgrades	Contract upgrade events
apps	Collection/app records
appTokens	Individual NFT token records
appTokenMints	Mint event records
appTokenTransfers	Token transfer history

Event Handlers (7 events)

Event	Handler
AppFactoryContract:AppCreated	Creates app record in database
SimpleAppContract:TokensMinted	Records mints, creates token records
OwnerTokenContract:OwnerTokenMinted	Records owner token creation
SimpleAppContract:Transfer	Token transfer tracking
OwnerTokenContract:Transfer	Owner token transfer tracking
ProxyAdmin events	Contract upgrade tracking

All events are broadcast in real-time via Socket.io.

Relevance to Diamond Architecture

Ponder Concept	Diamond Equivalent
AppCreated event	CollectionCreated event from DiamondFactory
TokensMinted event	Transfer events from ERC721AFacet
Schema: apps → appTokens	Same pattern: collections → tokens
Socket.io real-time	Reusable unchanged

Bottom line: Schema design and event handler patterns are directly applicable. Rename App → Collection, update event signatures for Diamond contracts, and the indexer works. Not needed for Phase 1 since custodial minting means we track all data server-side. Add in Phase 6 for secondary market features.

Full Documentation

See emprops-ponder Documentation for complete schema, event handlers, API endpoints, and WebSocket setup.

3. emprops-react-web3 (React Integration Patterns)

Path: /Users/the_dusky/code/emprops/nft_investigation/emprops-react-web3Stack: React 18.3.1, Wagmi 2.0.0, RainbowKit 2.0.0, TanStack Query 5.0.0, Viem 2.0.0, Socket.io-client 4.8.1

Two-Adapter Architecture

This package demonstrates a clean separation between read and write operations:

┌─────────────────────────────────────────────────────┐
│                EmPropsProvider                        │
│  (wraps Wagmi + RainbowKit + QueryClient)            │
├──────────────────────┬──────────────────────────────┤
│    PonderAdapter     │       WagmiAdapter            │
│  (reads from Ponder) │  (writes via wallet signing)  │
│  ├─ HTTP API calls   │  ├─ Gas estimation            │
│  ├─ ABI management   │  ├─ Tx execution              │
│  └─ Socket.io subs   │  └─ Wallet connection         │
└──────────────────────┴──────────────────────────────┘

Hooks

Hook	Type	Description
`useEmProps`	Provider	Access both PonderAdapter and WagmiAdapter
`useEmPropsQuery`	Read	React Query + Socket.io auto-invalidation
`useEmPropsTransaction`	Write	Transaction execution with status tracking
`useGetSimpleApps`	Read	List collections from Ponder
`useMintToken`	Write	Mint via wallet signing
`useCreateSimpleApp`	Write	Create collection via factory

Relevance to Diamond Architecture

Pattern	Reuse Status
Two-adapter pattern (read/write separation)	Excellent — directly applicable
React Query + Socket.io auto-invalidation	Production-ready pattern
EmPropsProvider (Wagmi + RainbowKit wrapper)	Needs network parameterization (currently hardcoded to localhost:8545)
Transaction hooks	Inform studio hook design for Arbitrum

Bottom line: Architecture patterns are excellent reference material. The two-adapter pattern (reads from indexer, writes via wallet) is the right approach for Phase 5+ when user-signed transactions are added. For Phase 1 (custodial), writes go through the API instead of wallet.

Full Documentation

See emprops-react-web3 Documentation for complete provider setup, adapter patterns, and hook implementations.

4. emprops-api (Java — Legacy Marketplace Backend)

Path: /Users/the_dusky/code/emprops/core-services/emprops-apiStack: Java, Spring Boot, Spring Data JPA, Gradle Estimated Size: ~5,500+ LOC

Key Entities

Entity	Description
Project/Collection	Collection metadata, status, blockchain, pricing
Token	Individual NFT with metadata, ownership, generation status
Sales	Marketplace listings, purchases, pricing
Events	Audit trail of all platform actions
Royalties	Royalty configuration per collection
Profile	User profiles with wallet associations
Contract Registry	ABI storage and contract address mapping

Key Capabilities (Feature Spec for Restoration)

Feature	Endpoint Pattern	Restoration Priority
Collection CRUD	`/api/projects/*`	Already in turbo monorepo
Token management	`/api/tokens/*`	Phase 2 (API endpoints)
Marketplace listings	`/api/sales/*`	Phase 5+ (OpenSea links first)
Secondary sales tracking	`/api/sales/private/*`	Phase 6 (Ponder indexer)
Floor/ceiling prices	`/api/projects/stats`	Phase 6
Event audit trail	`/api/events/*`	Phase 2 (API events)
Royalty configuration	`/api/royalties/*`	Phase 1 (RoyaltyFacet on-chain)
Profile management	`/api/profiles/*`	Already in turbo monorepo
Token trait filtering	`/api/tokens/features`	Phase 5 (metadata attributes)
Questionnaire-driven art	`/api/questionnaire/*`	Already exists as EmProps v2 variables

Bottom line: This is the feature spec — it documents everything the original marketplace could do. Most CRUD already exists in the turbo monorepo. Marketplace/sales features come later. On-chain features (royalties) are handled by Diamond facets.

5. emprops-open-api (Node.js — API Predecessor)

Path: /Users/the_dusky/code/emprops/emprops-open-apiStack: Node.js

Capabilities

Intermediary API between frontend and Java backend
Metadata management (token metadata JSON creation)
IPFS integration (pinning metadata and assets)
Collection rewards system
Generation endpoint routing

Relevance

Metadata patterns carried forward into the new GCS + CDN approach. The metadata JSON structure (name, description, image, attributes) follows the same ERC721 standard.

Bottom line: Reference for metadata patterns only. Functionality consolidated into apps/emprops-api in the turbo monorepo.

Migration Path Summary

Legacy Code                        →  New Diamond Architecture
─────────────────────────────────────────────────────────────────
emprops-hardhat contracts          →  Reference for Diamond facet code
emprops-hardhat factory            →  DiamondFactory replaces ERC1167
emprops-ponder indexer             →  Phase 6 (not needed for v1)
emprops-react-web3 patterns        →  Inform studio hook updates
emprops-api (Java) features        →  Feature spec for restoration
emprops-open-api metadata          →  GCS + CDN metadata pattern

Legacy Architecture — How the microservices worked together
Studio Code Inventory — All NFT code in emprops-studio
Diamond ADR — New architecture decision
Implementation Plan — Phased build plan

External NFT Repositories ​

Repository Summary ​

1. emprops-hardhat (Smart Contracts) ​

Contracts ​

Architecture Pattern ​

Database Integration ​

Relevance to Diamond Architecture ​

2. emprops-ponder (Blockchain Indexer) ​

Schema (8 tables) ​

Event Handlers (7 events) ​

Relevance to Diamond Architecture ​

3. emprops-react-web3 (React Integration Patterns) ​

Two-Adapter Architecture ​

Hooks ​

Relevance to Diamond Architecture ​

4. emprops-api (Java — Legacy Marketplace Backend) ​

Key Entities ​

Key Capabilities (Feature Spec for Restoration) ​

5. emprops-open-api (Node.js — API Predecessor) ​

Capabilities ​

Relevance ​

Migration Path Summary ​

Related Documentation ​

External NFT Repositories

Repository Summary

1. emprops-hardhat (Smart Contracts)

Contracts

Architecture Pattern

Database Integration

Relevance to Diamond Architecture

2. emprops-ponder (Blockchain Indexer)

Schema (8 tables)

Event Handlers (7 events)

Relevance to Diamond Architecture

3. emprops-react-web3 (React Integration Patterns)

Two-Adapter Architecture

Hooks

Relevance to Diamond Architecture

4. emprops-api (Java — Legacy Marketplace Backend)

Key Entities

Key Capabilities (Feature Spec for Restoration)

5. emprops-open-api (Node.js — API Predecessor)

Capabilities

Relevance

Migration Path Summary

Related Documentation