Comunifi

Communities constantly need to raise funds — for new initiatives, infrastructure, and shared goals. Today, they coordinate through centralized Web2 platforms (Reddit, Discord, Telegram) while relying on fragmented fintech tools (Venmo, Wise, bank transfers) for payments. This leaves them without control over their data, their funds, and the platforms they depend on. Crypto offers powerful alternatives, but UX friction has kept mainstream communities away.

ComuniFi unifies decentralized communication and peer-to-peer crowdfunding in one seamless platform. Built on Nostr for messaging and coordination, ERC-4337 Account Abstraction for simple wallet interactions, and PYUSD for stable, real world, spendable value — it enables chat-style crowdfunding without smart contracts, custodians, or escrow. Community members can post crowdfunding proposals, contribute to goals, and claim funds directly through familiar social-style interactions — all cryptographically signed and fully non-custodial.

Key Features

Seamless UX: Chat-style crowdfunding where Ethereum keys double as Nostr identities — same key, unified identity.

Frictionless Payments: Contribute and receive PYUSD instantly — no intermediaries, no escrow, just direct stablecoin transfers.

Real-World Utility: Because PYUSD is PayPal’s stablecoin, funds can be spent directly via PayPal checkout, bridging crypto and traditional commerce.

Fully Non-Custodial: Every action (post, contribute, claim) is signed and verifiable — no contracts, no custodians.

Comunifi is built by combining Nostr’s decentralized communication protocol with ERC-4337 account abstraction on Arbitrum, using PYUSD as the native payment medium. The result is a peer-to-peer crowdfunding system that runs without custodians, smart contracts, or centralized servers.

Core Architecture

Blockchain Layer: Arbitrum for fast, low-cost settlement of PYUSD transfers.

Account Abstraction: ERC-4337 user operations enable gasless and flexible transactions. We used Citizen Wallet’s bundler to collect, verify, and batch-submit these user ops.

Social Layer: Nostr provides the decentralized messaging layer. We use standard kind 1 messages with structured JSON metadata tags — preserving full compatibility with existing Nostr clients while embedding crowdfund data (goal, destination, user operation).

App Layer: The demo was built with Flutter, allowing the same codebase to run across macOS, iOS, Android, Windows, Linux, and Web. This makes the UX consistent across all platforms.

Relay Layer: A custom Go-based Nostr relay backed by Postgres handles persistence, event indexing, and replay of crowdfund data.

Technical Innovations

Shared Identity: Ethereum and Nostr both use the same elliptic curve (secp256k1). We leveraged this to unify signing — your Ethereum private key is also your Nostr identity, creating seamless social + financial integration.

Intent Cheques: Each contribution is a signed ERC-4337 user operation embedded in a Nostr reply. These operations are verifiable, time-bounded, and retryable, allowing asynchronous, contract-free crowdfunding.

Batch Execution: When a crowdfund is ready to claim, the app aggregates all user ops from Nostr replies and submits them to the Citizen Wallet bundler for gas-optimized batch execution.

Real-World Utility via PYUSD: Using PayPal’s PYUSD stablecoin makes crypto usable for real-world payments. Contributors can fund a crowdfund in PYUSD, and recipients can spend those funds directly through PayPal checkout — bridging Web3 coordination and Web2 commerce.

Demo Proof

Transaction: https://arbiscan.io/tx/0xd3a17e143ad9a716debd0b298e9f33a6d043522ea153dee21ecd673d1a43a0d3

DNS Record: https://www.nslookup.io/domains/comunifi.xyz/dns-records/#cloudflare

Look for tag: eth-global-online-2025:tx-hash:0xd3a17e143ad9a716debd0b298e9f33a6d043522ea153dee21ecd673d1a43a0d3

The demo shows real crowdfunding contributions and batch claims executed via the Citizen Wallet bundler, using PYUSD on Arbitrum — proving end-to-end decentralized coordination and real-world payment utility.