What API and data model would support a new Messaging workflow for hiring managers

Problem Statement Description

Product context: LinkedIn is Microsoft's professional network; its products include profiles, feed, jobs, recruiting, LinkedIn Learning, sales tools, messaging, and ads.

LinkedIn wants to introduce a new Messaging workflow tailored to hiring managers who need to communicate with candidates, recruiters, interviewers, and other internal stakeholders during the hiring process. The workflow should fit within LinkedIn’s professional messaging ecosystem while supporting hiring-specific context such as candidate identity, role relevance, conversation history, permissions, and collaboration needs.

You are asked to define the API and data model that would enable this workflow. The focus is not on UI design, but on the technical product foundation: what entities, relationships, states, permissions, events, and integrations are required so hiring managers can use Messaging reliably and securely as part of recruiting.

Assume this workflow may need to interact with LinkedIn member profiles, jobs, recruiter tools, company pages, notifications, search/recommendation systems, and potentially applicant tracking or CRM-like systems. The design should account for LinkedIn’s trust expectations, privacy constraints, network graph, and scale.

The experience should consider:

- Core user actions hiring managers need to perform within the messaging workflow, including initiating, continuing, sharing, and managing hiring-related conversations

- Key data entities and relationships needed to represent candidates, jobs, hiring teams, conversations, participants, permissions, message metadata, and workflow state

- API boundaries, request/response patterns, idempotency, pagination, filtering, search, and event handling for messaging and recruiting use cases

- Access control, consent, privacy, data retention, auditability, and separation between personal member messaging and company/hiring-context messaging

- Reliability requirements such as delivery guarantees, retries, ordering, deduplication, rate limits, abuse prevention, and graceful degradation

- Integration points with LinkedIn Recruiter, Jobs, notifications, profile data, calendaring/interview workflows, and external hiring systems where relevant

- Observability needs, including logging, metrics, tracing, error handling, and operational dashboards to monitor adoption, latency, failures, and policy violations

- Product and technical trade-offs around flexibility versus complexity, speed of launch versus long-term extensibility, and hiring-manager convenience versus candidate trust

Your goal is to describe a technically sound API and data model approach that can support a hiring-manager messaging workflow at LinkedIn scale, while making clear the assumptions, constraints, and trade-offs that would guide implementation and rollout.