L7 — Systems / Stripe Payment Systems
AI-native. Principal-led. Operator-stays. For small business owners who deserve top-of-market work at prices traditional consulting won't quote.

Stripe Payment Systems

Checkout, subscriptions, invoices, and platform fees with webhooks done right.

The problem

Payments are where small mistakes become real money problems. Most off-the-shelf setups break on edge cases: a webhook that is not verified, a subscription that does not sync, a fulfillment email that never fires. L7 builds payment systems with signature verification, clean state handling, and test-to-live discipline.

Who it’s for

Businesses that need checkout, subscriptions, invoices, platform fees, or payment-linked workflows built correctly and verified before they touch live money.

What L7 builds
01Stripe Checkout and on-page payment flows
02Subscriptions and recurring billing with synced account state
03Invoices and one-time charges
04Platform fees and split payments via Stripe Connect where the model calls for it
05Webhook handlers with signature verification, not unguarded endpoints
06Fulfillment and email flows triggered by verified payment events
07Test-mode and live-mode discipline so nothing ships on guesswork
Stack & components
Stripe (Checkout, Billing, Connect, Webhooks)Next.js 14SupabaseResendVercel
Proof — L7 built this
Case study
Scat Pack CLT
Full dog-waste SaaS shipped to production in 24 hours.
Read →
Case study
Shariel's Lashes
Premium lash studio launched end-to-end: brand, site, booking, ops.
Read →
Principal-led

Every Stripe Payment Systems engagement runs through Kenneth Leftwich (Founder & Principal — former SVP Strategy Execution at Tirebuyer/Treadsy, ex-Gartner Fortune 50 partner, $106M optimized at Lowe's). The principal sets the standard; the SymbAIotic Shift™ and L7's governed AI agents deliver under human review.

How to start
Start a project at /start describing what you charge for and how. L7 confirms the right Stripe model before any build begins.
Start a project →See past work