Service marketplace and trust platform

9jaConnect

A multi-sided marketplace backend for discovery, service coordination, and trust decisions.

Role
Backend engineering for marketplace coordination
Stack
  • Python
  • FastAPI
  • PostgreSQL
  • Alembic

Problem

The problem

Connecting customers with service professionals requires more than a searchable directory. Requests, quotes, conversations, identity checks, reviews, disputes, recurring arrangements, and platform decisions must remain consistent across a multi-sided marketplace.

System model

A connected operational flow

CustomersProfessionalsMarketplace workflowsTrust & disputesAdministrative controls

System flow: Customers to Marketplace workflows; Professionals to Marketplace workflows; Marketplace workflows to Trust & disputes; Marketplace workflows to Administrative controls.

Context

A marketplace has more than one source of truth

9jaConnect coordinates customers, service professionals, and platform operators. Its core challenge is preserving consistent state as people discover services, request help, exchange quotes, communicate, and resolve issues.

Responsibility

Model the connected marketplace workflow

I worked on backend capabilities around professional discovery, requests, quotes, messaging, reviews, identity checks, disputes, notifications, referrals, and administrative controls. The system has to keep decisions intelligible across multiple participant roles.

Engineering decisions

Preserve state through change

FastAPI and PostgreSQL provide a clear service and data foundation, while Alembic supports deliberate schema evolution as marketplace workflows develop. The result focuses on coordinating trust and service work, not merely listing professionals.

Outcome

What the system enables

Supported consistent service-request, communication, and trust workflows across customers, professionals, and platform administration.