Identity Reconciliation

A production REST API that solves a real e-commerce problem: the same customer uses different email/phone combinations at checkout, creating duplicate contact records. This service reconciles them into a single identity.

How It Works

1. New contact — creates a primary record
2. Returning contact — finds the oldest primary, creates a secondary record linked to it
3. Merging chains — when new data bridges two existing contact groups, the younger primary is demoted to secondary and all records are consolidated

Architecture

• Node.js + TypeScript with Express
• PostgreSQL database with Prisma ORM
• Single POST /identify endpoint that returns a fully consolidated contact object with all known emails, phones, and secondary IDs
• Deployed and live at https://identity.musavirchukkan.in

Database Schema Contacts table with linked_id (self-referencing FK) and link_precedence enum (primary / secondary) — effectively a linked-list resolved at query time.

API POST /identify — accepts email and/or phoneNumber, returns { primaryContactId, emails[], phoneNumbers[], secondaryContactIds[] }