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Case study / Payment infrastructure

F18 Pay

A merchant payment layer for Bitcoin and Ethereum stores that need invoices, payment requests, branded checkout surfaces, wallet controls, and clearer operational state in one place.

View live productRead the build story
BTC / ETHStore types

Separate Bitcoin and Ethereum flows keep configuration and support simple.

QR checkoutPublic flow

Public invoice pages show the amount due, QR address, and current status.

Email-gatedWallet access

Sensitive wallet actions sit behind verification instead of an open download.

Development journey

From a payment surface to a system merchants could actually operate.

Flat18 treated F18 Pay as a controls and trust problem. The product had to help merchants create stores, manage brand and wallet state, issue invoices, create payment requests, and support payments without hiding the parts that usually go wrong.

01 / Friction

Merchants needed more than a checkout link.

F18 Pay had to handle stores, invoices, request links, wallet access, and brand controls without forcing merchants to stitch together separate tools.

02 / Product shape

The store became the centre of the system.

Each store carries its own identity, currency mode, and operational settings. That keeps Bitcoin and Ethereum workflows separate and easier to support.

03 / Reliability

Security and state had to stay visible.

Wallet access sits behind verification, invoice states stay clear, and payment requests carry enough context to support a real transaction later.

Product surfaces

Designed around the moments where payment products usually break.

F18 Pay is not just a QR checkout. It is an operating layer for stores, invoices, requests, wallet access, and payment entry points.

Payment assets

Make the checkout entry points fit the store.

Buttons and payment pages can be generated in the same brand system, so merchants can embed a payment experience instead of a generic link.

Invoices

Keep payment state visible.

Invoice tables show due amounts, statuses, and date ranges so support teams can answer questions quickly.

Payment requests

Create a clean trail for money requests.

Request links, recipient emails, and status fields keep follow-up clear after a request leaves the dashboard.

Store summary
Store settings
Wallet controls
Invoices
Payment requests

Delivered for confidence

Store identity, wallet access, invoices, payment assets, and request flows stay visible in one place, which makes the whole payment system easier to operate and support.

LiveDiagnosis: payments were split across too many surfacesSolution: store-centred payment systemOutcome: clearer checkout and support flows

Flat18 treated F18 Pay as a controls and trust problem. The product had to help merchants set up stores, issue invoices, manage wallet access, and present a public payment flow without hiding the important state.

Problem found

Merchants needed stores, invoices, requests, wallets, and public payment pages in one system, not a pile of disconnected tools.

Flat18 diagnosis

The store had to be the centre of the product. If the merchant could not see state, the support load would only move elsewhere.

Solution shipped

We built store setup, payment assets, invoice tracking, request flows, wallet verification, and public payment states into one operating layer.

Customer value

Merchants can support real payments with clearer status, fewer hand-offs, and less guesswork when something needs checking.

What Flat18 handled

  • Turned a long-running payments codebase into a coherent product story
  • Designed the information architecture around stores, invoices, wallets, requests, and public payment pages
  • Kept operational detail visible without overwhelming the merchant
  • Preserved the technical depth instead of hiding it behind a simplified shell

Stack

Vue 3VitePiniaVue RouterNode.js + ExpressNeon Postgresbitcoinjs-libethersMailgun

Need a payment workflow this controlled?

Flat18 can turn merchant operations into a clear product with the right screens, state, and support flow.

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