The original web API method for uploading files to Slack, files.upload, is being sunset on March 11, 2025.
As of May 16, 2024, newly-created apps are no longer able to use this API method.
Existing apps & integrations should migrate away from files.upload and instead leverage a combination of two APIs: files.getUploadURLExternal and files.completeUploadExternal. The use of these two methods is more reliable, especially when uploading large files.
A detailed breakdown of how to use these two API methods is described in our Uploading files documentation.
Over the past several years, the files uploaded by users have grown larger and the underlying stacks serving Slack have evolved. To best serve the file upload trends of today and tomorrow, we're moving completely to a more asyncronous upload and processing system.
Instead of uploading a file using a multipart POST to files.upload and waiting for an affirmative response at the end of the HTTP request, you'll now send the file upload data to our optimized files.getUploadURLExternal method and then fill us in on what you sent with files.completeUploadExternal.
You must complete these changes by March 11, 2025 with these key schedule points to keep in mind:
files.upload API. Existing apps will be able to continue using files.upload until it is sunset.files.upload and Slack workspace admins managing apps that use files.upload.files.upload will be sunset and no longer accessible.A detailed breakdown of how to stop using files.upload and start using the two new methods is described in our Uploading files documentation.
If you already use our developer tooling like our node.js, Python or Java SDKs, including the Bolt suite of application frameworks, then the migration should be made easier: these libraries provide a “v2” upload convenience method that wraps around the files.getUploadURLExternal and files.completeUploadExternal methods.
In particular:
@slack/web-api package exposes a uploadV2 method, which is also available within Bolt JS’s client handler parameter.files_upload_v2 method, which is also available within Bolt for Python’s client handler parameter.FilesUploadV2Request class utilizing the new methods.As of May 16, 2024, newly-created Slack apps are no longer able to access the files.upload API. Existing apps created prior to May 16, 2024 will be able to continue using files.upload until March 11, 2025.
If you choose to do absolutely nothing before March 11, 2025, and your app continues to attempt to use files.upload, your app may quite possibly break or become unusable. At the very least, it won't be uploading files.
There are two keys dates to keep in mind:
files.upload API. All new apps must use the new methods.files.upload API will be sunset and no longer available. All apps, new and old, must use the new methods by this date.If you have questions or concerns about the deprecation and retirement of our files.upload method, please contact us.