← Back to projects

Case study

Parmelia

A stablecoin payments app for people who want to get paid and pay others, not learn how to operate a wallet.

Alpha · Arbitrum Sepolia · test funds
Parmelia
My role
Product and development lead
Focus
Self-custodial USDC payments
Network
Arbitrum Sepolia
Stack
React, Solidity, Foundry, and Cloudflare

The problem was not the blockchain. It was the experience.

Receiving a crypto payment often means explaining addresses, networks, gas, seed phrases, and transaction hashes. For many people, that learning curve appears before they can do something as simple as getting paid.

With Parmelia, I wanted to reverse that relationship: start with familiar actions —sharing a link, scanning a QR code, or typing a name— and keep the infrastructure underneath the interface.

Three decisions that shaped the product

01

Passkeys instead of seed phrases

The account is authorized with a fingerprint or face through WebAuthn. The user remains in control without starting with a recovery phrase to memorize.

02

Account abstraction to hide gas

ERC-4337 smart accounts make it possible to sponsor operations and batch calls. Paying can feel like a product action instead of a wallet procedure.

03

Links, QR codes, and usernames as the interface

Parmelia builds on habits people already have. The recipient and amount are readable before confirmation, and every movement ends with a verifiable receipt.

What I built

I led the project and worked across the product, onchain architecture, and infrastructure needed to demonstrate the full flow.

  • Mobile-first flows for sending, charging, scanning QR codes, swapping, reviewing activity, and saving contacts.
  • Passkey smart accounts, deterministic deployment, batched calls, guardian recovery, and a paymaster with short-lived signatures.
  • A Cloudflare backend with D1, RPC failover, anti-abuse protection, and external-deposit tracking.
  • Uniswap-routed swaps, transaction receipts, an installable PWA, and push notifications.

What works at this stage

The documented build lets people test the core journey with test funds:

  • Create a passkey account without a seed phrase.
  • Request payments through links and QR codes.
  • Pay a username, a QR code, or an address.
  • Swap assets inside the application.
  • Review activity and onchain receipts.

Explore the project