Slack Updates APIs and Improves Third-Party Integrations

Slack announced a comprehensive revision of its APIs and third-party app integration system, focused on security, permission granularity, and ease of configuration. The update is the most significant since the introduction of the Block Kit APIs in 2019 and responds to recurring developer criticism about the complexity of the OAuth authentication system and the difficulty of debugging integrations in production environments.

New Permissions Model

The centerpiece of the update is the transition to a granular permissions model based on declarative scopes. Previously, a Slack app needed to request broad permissions — such as "read all channels" — when it only needed access to a specific channel. The new system allows the app to declare exactly which resources it needs to access, with which operations, and in what scope, with the authorization process reflecting those restrictions in a way that is verifiable by the workspace administrator.

For corporate IT administrators, the change is significant: the app management panel now displays a detailed audit log of every action taken by integrations, including which messages were read, which files were accessed, and which webhooks were called. This facilitates compliance with corporate security policies and data access audits.

Improvements for Developers

The new Slack Developer CLI simplifies the local development cycle with function hot reload, platform event simulation without needing a real workspace, and a debug mode that intercepts and displays in real time all API calls made by the integration. Documentation was completely rewritten with interactive examples and an integrated test sandbox. Changes are backward-compatible: existing apps continue working, but gain access to new capabilities upon a manifest update.