# What is Slack App?

Also called Slack Bot, Slack Integration.

A Slack app is an integration installed into a Slack workspace that can post messages, respond to events, add slash commands, and render interactive surfaces. It authenticates with scoped tokens granted at install time and receives activity through the events subscription or a socket connection. Apps act under their own identity or, with permission, on a user's behalf.

Installation grants a set of scopes that bound what the app can read and do, such as reading messages in channels it has been added to or posting as itself. Slack then pushes subscribed events to the app, which replies through the web API. Interactive elements, modal dialogs, and the app's home tab give it surfaces beyond plain messages.

Because a workspace is a shared space, an app that posts too much is quickly muted or removed. The conventions that work are threaded replies rather than channel noise, ephemeral messages visible only to the person who triggered them, and pushing detail into a modal instead of a wall of text. Channel membership, not workspace installation, determines what an app can see.

The recurring mistakes are over requesting scopes at install, ignoring the differences between public channels, private channels, and direct messages, and treating message content as trustworthy. Slack also expects fast acknowledgment of an interaction, so long running work is acknowledged first and completed asynchronously. Enterprise installations add organization wide policies that can restrict which apps run at all.

As a channel for an assistant, Slack has an unusual property: the conversation is already visible to a team. That makes it excellent for work that benefits from witnesses, such as approvals, incident updates, and shared lookups, and poor for anything personal or sensitive, which belongs in a direct message or behind a link to an authenticated page.

## Key points

- Scoped tokens at install define exactly what the app may do
- Events are pushed to the app; replies go through the web API
- Visibility follows channel membership, not workspace installation
- Threads and ephemeral messages keep channels quiet
- Interactions need fast acknowledgment, with work completed after

## In practice

A support team installs an app into their escalations channel. When a customer reports an outage, a teammate types a slash command with the account name. The app opens a modal to collect severity and impact, then posts a threaded summary showing the account's plan, region, and recent errors. The person who ran the command sees a private confirmation, and the channel sees one tidy message.

## Related terms

- [Microsoft Teams App](/en/glossary/microsoft-teams-app)
- [Telegram Bot](/en/glossary/telegram-bot)
- [Omnichannel](/en/glossary/omnichannel)
- [Channel Routing](/en/glossary/channel-routing)
- [Chatbot](/en/glossary/chatbot)

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