Stellar POS

span 03 · write-upspan 03 · write-up

The problem

Retail operators needed one platform for in-store checkout, online channels and live numbers — across multiple locations, with hardware that a store manager could set up without a technician.

What I built

As the startup's full-stack lead I was a key contributor to Stellar POS from zero to production:

• Real-time transactions across store locations on Node.js, Express and PostgreSQL, with Redis on hot read paths for live KPIs.
• Queue-backed webhook ingestion for Shopify, WooCommerce and Global Payments, decoupling external events from internal state so a burst of orders never blocks checkout.
• Tenant-level RBAC so multiple operators manage locations concurrently with strict access boundaries.
• Plug-and-play hardware onboarding that cut device setup to minutes.

Why it matters for agents

The same patterns — asynchronous ingestion, isolation between tenants, idempotent processing of external events — are what keep tool-using agents reliable.