DisputeShield

A script tag, and the clock starts.

• Python
• Django
• PostgreSQL
• Redis
• Celery

The problem

A fintech owes its customers a way to file a dispute and owes its regulator an auditable record of what happened next. Building that means building a ticketing product, which nobody wants to do.

DisputeShield is a sandboxed cross-origin widget for the customer and an SLA-tracked, immutably audited case system for compliance.

What I built

• An embeddable widget — one script tag — plus a session-token API, with no cross-origin access to the host page.
• A Celery-driven SLA engine that alerts before the breach, not after it.
• Every state transition hash-chained and append-only, enforced at the database layer by trigger rather than by convention.
• A regulator-ready export of the whole case history.

Decisions worth naming

• The clock cannot be paused, because a pausable clock is an abusable one.
• There is no code path to a payment, and that is enforced by a call-graph test rather than by a promise in a README.