Outlook and Teams scheduling connector for ADP time-off

When an employee's PTO is approved in ADP, their Outlook calendar doesn't know. When a manager looks at team availability in Teams, they can't see who's out. The complaint is specific: users want 'integration with Outlook calendar for PTO requests.' Right now the workflow is: request in ADP, approval in ADP, then the employee manually blocks their calendar, then they tell their team in Slack, then the manager updates the team tracker. Four manual steps after the system has already processed the decision.

The reason this isn't fixed is that ADP sells to HR buyers, not to IT buyers. IT buyers are the ones who manage M365 integrations. HR bought ADP, got the HR features, and has no authority or budget to commission a custom integration — even if they know it's broken. The M365 admin has no idea there's a problem. This structural buyer mismatch means the gap sits in between two teams neither of whom owns it.

What's needed is a connector that listens to ADP's time-off approval events via webhook or polling, then writes a calendar block to the approved employee's Outlook calendar automatically, optionally posts a message to a configured Teams channel, and updates a shared 'who's out' calendar that managers can subscribe to. The employee gets asked once to authorize their calendar. After that, every approved PTO flows through without any manual action.

The same complaint extends to scheduling: users want to 'switch places with a workmate' using the ADP system, which is impossible when the schedule lives in ADP but all coordination happens in Teams or email. A lightweight shift-swap notification via Teams — triggered by ADP schedule changes — closes that loop without rebuilding scheduling from scratch.

This recurs with every PTO request, every schedule change, every new employee onboarded. Calendar fragmentation isn't a one-time cleanup; it's a continuous leak. The cost is real: managers make staffing decisions with incomplete information, employees get blamed for 'not telling anyone' when the system simply never told anyone on their behalf.

What to build

Build an M365-connected middleware service that subscribes to ADP Workforce Now time-off approval events, writes calendar blocks to the approved employee's Exchange/Outlook calendar, posts configurable notifications to a designated Teams channel, and maintains a shared 'team out-of-office' calendar — requiring one-time OAuth consent from each employee and a one-time M365 admin consent for the Teams/calendar write scope.

Where to start

Start with companies that are already using Microsoft Teams as their primary communication tool and have explicitly been told by their IT team that ADP has no native Teams app — this is a documented gap and a warm opening because IT already knows the problem exists.

The hard part

Getting both the ADP API credentials and the M365 admin consent in the same sales conversation is hard — HR buys ADP access and IT controls M365 permissions, and getting both to say yes at the same time often stalls deals in mid-market accounts.

How it makes money

Flat monthly fee per company based on employee count tiers (e.g., $99/month up to 100 employees, $249/month up to 500), since the value is the same regardless of how often PTO is approved.