Upload File
slack.upload_file
ActionChat & messagingconnection required
Calls the Slack Web API with the connection's bot token.
Upload a file with Slack's current external-upload flow and share it into a channel.
Connection
- Required
- Yes — the node will not save without one
- Auth type
- API key
- Providers
- Slack
- Secret shape
- the Slack bot token (xoxb-…), or {"token": "xoxb-…"}
- Resolved by
- config.connection_id, else node.connection_id
Configuration
9 fields, 2 required. A dotted path is a nested object and name[] an array of objects — the editor renders the same tree.
| Field | Type | Required | Default | Constraints | Example |
|---|---|---|---|---|---|
filename The file name, with its extension — Slack types the file from it. | string | Yes | — | — | — |
body The file content: text, or a base64 blob from an upstream file step. | string | Yes | — | — | — |
content_encoding Set to 'base64' when body is a base64 blob (e.g. from a download_archive node). Defaults to the upstream file's encoding, else text. | string | No | — | one of "text", "base64" | — |
title The title shown above the file in Slack. Defaults to the filename. | string | No | — | — | — |
channel_id Channel id to share the file into. Left empty, the file stays private to this app. | string | No | — | — | — |
initial_comment A message posted with the file. Supports {{ }}. | string | No | — | — | — |
thread_ts Share the file as a reply in this thread (the parent message's ts). | string | No | — | — | — |
snippet_type Syntax to highlight a text snippet with, e.g. python or sql. | string | No | — | — | — |
alt_txt Description of an image for screen readers. | string | No | — | — | — |
Output
One shape.
result
| Field | Type | Example |
|---|---|---|
ok Always true; a failure raises instead. | boolean | true |
file_id The Slack file id (F…) of the uploaded file. | string | — |
filename The file name that was uploaded. | string | — |
title The title Slack stored for the file. | string | — |
channel_id The channel it was shared into, or empty. | string | — |
files The file objects Slack returned for the completed upload. | array | — |
{
"channel_id": "",
"file_id": "",
"filename": "",
"files": [],
"ok": true,
"title": ""
}Notes
- The bot must be a member of a private channel before it can act there (Slack answers not_in_channel otherwise).
- Slack rate-limits each Web API method on its own tier; a throttled call fails with the number of seconds to wait and is safe for the node's retry policy to repeat.
- files.upload is retired; this node runs getUploadURLExternal → POST bytes → completeUploadExternal, which is the supported flow.
- The content is held in memory and capped by MANTLE_BINARY_MAX_BYTES; a larger file fails the step instead of exhausting the worker.
Templates that use Slack
See Upload File run in a workflow.
In a technical demo we add the Slack connection, drop the node on the canvas and let Workflow Health pre-flight it before the first real run.