Slack & Microsoft Teams Integration

An integration that connects an application with Slack and Microsoft Teams, allowing users to receive important application notifications directly in the tools they already use for communication.

Integrations settings page showing Slack and Microsoft Teams connected, with other available integrations listed below

The idea

This was my internship project, built for an accounting platform. Teams often spend a large part of their day working in communication platforms such as Slack and Microsoft Teams. Important application updates — findings or issues the system flagged — can easily get lost when users have to constantly switch between systems and log in to check.

The goal was to push these notifications straight from the accounting system into the tools people already use to communicate, so users could be alerted the moment something needed their attention, without having to go looking for it themselves.

My role

I was the project lead for the integration, working across both the frontend and backend to design and implement the feature.

I helped shape the integration, worked through the technical requirements, and coordinated the implementation needed to connect the application with both platforms.

What I built

Slack integration — Connect an account and receive application notifications in Slack.
Microsoft Teams integration — Provide the same notification workflow for Teams users.
OAuth authentication — Securely connect external accounts without handling user credentials directly.
Background workflows — Process notifications asynchronously to keep the main application responsive.
Product analytics — Track how the integration is being used and identify opportunities for improvement.

Slack settings page listing workspace members and their linked accounts

General settings page for choosing the daily digest channel and toggling real-time notification channels

Example Slack notifications for a status change and an @mention

Example Microsoft Teams notifications for a status change and an @mention

Technical implementation

The frontend was built with React and TypeScript, while the backend uses Node.js, tRPC, and PostgreSQL.

OAuth was used to securely connect external accounts, with Temporal handling background workflows and PostHog providing product analytics.

What I focused on

The project required more than simply connecting two APIs. I focused on creating a reliable integration that fits naturally into existing workflows, while keeping the experience simple for users and the underlying system robust enough to handle asynchronous notifications.