NestJS Developer — Add Shift Handover to an Existing SaaS

We need a Node.js / NestJS developer to add a shift handover feature to our existing multi-tenant SaaS platform for security companies. The system already manages guards, supervisors, and their shifts. We want a code-based handover workflow: the outgoing employee generates a code, and the incoming employee enters it to complete the handover and start their shift. You will integrate this feature into the existing backend, following the project's structure and permission rules. Experience with NestJS, TypeScript, and multi-tenant applications is required. This is a fixed-price project. Please share a relevant example of your work and a preliminary cost and timeline estimate. Further details will be discussed with shortlisted candidates.