Support slack_file for videos in Block Kit (parity with images)

[osmanpontes]

Problem

Block Kit currently supports slack_file references for images, which allows apps to safely render private Slack-hosted files inside messages without requiring public URLs.

However, this capability is limited to images only. There is no equivalent way to reference Slack-hosted video files (file_id) in Block Kit, even though Slack already supports:

• Video files uploaded to Slack
• A native video block that requires public or embeddable URLs

This creates an inconsistency: images can be rendered from private Slack files, while videos cannot.

Goal

Provide first-class support for using Slack-hosted video files (slack_file) inside Block Kit, similar to how images currently work.

This would allow apps to:

• Upload a video using files.uploadV2
• Reference the resulting file_id in Block Kit
• Render the video inline without requiring a public URL or external hosting

Why this matters

• Many apps handle sensitive or private video content that should not be publicly accessible
• Hosting videos externally (S3, YouTube, etc.) adds operational and security overhead
• Image blocks already solve this problem elegantly via slack_file
• Feature parity between images and videos would greatly improve developer experience

Proposed direction (non-binding)

Examples of possible approaches:

• Allow slack_file as a source for the existing video block
• Or introduce a dedicated video element that accepts { type: "slack_file", file_id }
• Update @slack/types to reflect the new capability

This issue is primarily about API and SDK support; the exact implementation details are up to the Slack team.

Related context

• slack_file is already supported for images in Block Kit
• The video block currently only supports external URLs
• There does not appear to be an existing feature request covering video + slack_file support

Happy to help clarify use cases or test early implementations if needed.

Packages:

Select all that apply:

• @slack/web-api
• @slack/rtm-api
• @slack/webhooks
• @slack/oauth
• @slack/socket-mode
• @slack/types
• I don't know

Requirements

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