Payment systems that reconcile at the end of the month

Meshulam + Strapi — $1M+ per year, annualized

At One Digital I built an end-to-end payment system on the Meshulam SDK inside a Strapi backend, processing over $1,000,000 a year in transaction volume. The interesting half was never the charge call. It was everything that has to stay true afterwards:

• Webhook reconciliation. Gateways retry. They deliver out of order, they deliver twice, and occasionally they deliver three weeks late. Getting a replayed webhook to update the order it already created, instead of creating a second one, is most of the work in any payment integration.
• Lifecycle hooks as the single source of truth. Order state transitions live in Strapi lifecycle hooks rather than scattered through controllers, so a payment can't be marked paid down one code path and left pending down another.
• Invoices generated automatically. Dockerized Puppeteer on Azure Functions renders the PDF invoice as part of the payment flow, not as a monthly chore, which is the difference between finance trusting the system and finance keeping a parallel spreadsheet.

Stripe — billing my own SaaS, in production

GhostChat runs on Stripe subscription billing I built and still operate. Two decisions there are worth stealing for any subscription product:

• Entitlements resolve from the subscription itself. What a customer can do is derived from the Stripe price they're actually on, not from a plan name copied into your own database at signup. Those two drift apart the first time someone upgrades mid-cycle, and once they drift you are reconciling access by hand.
• Repricing is a new Price, not a migration. Because entitlement is read from the subscription itself, changing what you charge means publishing a new Price object rather than running a script against live customers at 2am — and you decide deliberately, per entitlement, which existing subscribers move.

There is a particular kind of care you develop when the failed-payment webhook is your own revenue, and that's the standard I bring to client billing systems.

KaspaWoo — open-source crypto gateway

A production Kaspa payment gateway for WooCommerce, open-sourced on GitHub. It's non-custodial: payments derive to the merchant's own wallet, never mine. The address derivation had to be its own package because no lightweight JavaScript option existed — the official tooling is a WASM build far too heavy to sit inside a WordPress plugin — so I wrote kaspa-simple-wallet in pure JS and published it MIT: watch-only derivation from a KPUB/XPUB, Kaspium-compatible, so the store never holds a private key. It is written to the WooCommerce gateway API properly, which means refunds and order states behave the way the rest of the admin expects them to.

E-signatures and contract flow

At Hertz Furniture I integrated SignNow for e-signatures on PDF quotes, cutting contract turnaround time by 90%. Payments rarely live alone — they sit next to quotes, contracts, invoices, and a CRM that all need to agree with each other.