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EthanLabs

Full-stack developer creating modern web applications and digital solutions.

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Thoughts on web development, technology trends, and best practices

View All Posts Development InvocaCare Architecture React System Design

system-design - Blog

#system-design

2 posts tagged with system-design

Diagram contrasting two dev tools side by side: dev-cli.ts going through the real service layer as the safe path that can't produce orphaned records, versus repair-orphans.sh operating on raw AWS SDK calls as a deliberately separate, deliberately-not-TypeScript exception path

Jun 20, 2026

Two Tools, One Rule: Why Dev Tooling Goes Through the Service Layer (Except When It Doesn't)

A raw-SDK cleanup script once deleted zero records it should have deleted, because it reimplemented entity shape independently of the real write path. The fix: dev tooling now calls the same service functions production does — with one deliberate, structurally-separate exception for state the service layer can't reach

InvocaCare Architecture

Diagram of a Stripe subscription with two line items — a flat base fee and a per-seat overage — next to a four-state billing lifecycle: trial, active, suspended, cancelled

May 23, 2026

Modeling Billing So the Code Matches the Pricing Page, Not the Other Way Around

A base-fee-plus-seat-overage pricing model needs two Stripe subscription items, not one; webhooks confirm state changes but never decide them; and a single four-state subscription machine replaces a separate `isActive` flag that could quietly disagree with it

InvocaCare Architecture

billing

developer-experience

testing

system-design

stripe

system-design