files.upload

Uploads or creates a file.

File threads are here

A new file commenting experience arrived on July 23, 2018. Learn more about what's new and the migration path for apps already working with files and file comments.

This method allows you to create or upload an existing file.

Arguments

tokenRequired

Authentication token bearing required scopes.

Examplexxxx-xxxxxxxxx-xxxx

channelsOptional

Comma-separated list of channel names or IDs where the file will be shared.

ExampleC1234567890,C2345678901,C3456789012

contentOptional

File contents via a POST variable. If omitting this parameter, you must provide a file.

Example...

fileOptional

File contents via multipart/form-data. If omitting this parameter, you must submit content.

Example...

filenameOptional

Filename of file.

Examplefoo.txt

filetypeOptional

A file type identifier.

Examplephp

initial_commentOptional

The message text introducing the file in specified channels.

ExampleBest!

thread_tsOptional

Provide another message's ts value to upload this file as a reply. Never use a reply's ts value; use its parent instead.

Example1234567890.123456

titleOptional

Title of file.

ExampleMy File

Present arguments as parameters in application/x-www-form-urlencoded querystring or POST body. This method does not currently accept application/json.

You must provide either a file or content parameter.

The content of the file can either be posted using an enctype of multipart/form-data (with the file parameter named file), in the usual way that files are uploaded via the browser, or the content of the file can be sent as a POST var called content. The latter should be used for creating a "file" from a long message/paste and forces "editable" mode.

In both cases, the type of data in the file will be intuited from the filename and the magic bytes in the file, for supported formats.

Sending a valid filetype parameter will override this behavior. Possible filetype values can be found in the file object definition.

Files uploaded via multipart/form-data will be stored either in hosted or editable mode, based on certain heuristics (determined type, file size).

The file can also be shared directly into channels on upload, by specifying an optional argument channels. If there's more than one channel name or ID in the channels string, they should be comma-separated.

There is a 1 megabyte file size limit for files uploaded as snippets.

Upload files and images into message threads by providing the thread parent's ts value with the thread_ts parameter.

The initial_comment field is used in messages to introduce the file in conversation.

If you only specify a filename, we remove the file extension and populate the file's title with the remaining value. So, if you want the file's extension to be shown in Slack, you must include it in the title argument when uploading it.

Response

By default all newly-uploaded files are private and only visible to the owner. They become public once they are shared into a public channel (which can happen at upload time via the channels argument).

If successful, the response will include a file object.

Success response after uploading a file to a channel with an initial message

{
    "ok": true,
    "file": {
        "id": "F0TD00400",
        "created": 1532293501,
        "timestamp": 1532293501,
        "name": "dramacat.gif",
        "title": "dramacat",
        "mimetype": "image/jpeg",
        "filetype": "gif",
        "pretty_type": "JPEG",
        "user": "U0L4B9NSU",
        "editable": false,
        "size": 43518,
        "mode": "hosted",
        "is_external": false,
        "external_type": "",
        "is_public": false,
        "public_url_shared": false,
        "display_as_bot": false,
        "username": "",
        "url_private": "https://.../dramacat.gif",
        "url_private_download": "https://.../dramacat.gif",
        "thumb_64": "https://.../dramacat_64.gif",
        "thumb_80": "https://.../dramacat_80.gif",
        "thumb_360": "https://.../dramacat_360.gif",
        "thumb_360_w": 360,
        "thumb_360_h": 250,
        "thumb_480": "https://.../dramacat_480.gif",
        "thumb_480_w": 480,
        "thumb_480_h": 334,
        "thumb_160": "https://.../dramacat_160.gif",
        "image_exif_rotation": 1,
        "original_w": 526,
        "original_h": 366,
        "permalink": "https://.../dramacat.gif",
        "permalink_public": "https://.../More-Path-Components",
        "comments_count": 0,
        "is_starred": false,
        "shares": {
            "private": {
                "D0L4B9P0Q": [
                    {
                        "reply_users": [],
                        "reply_users_count": 0,
                        "reply_count": 0,
                        "ts": "1532293503.000001"
                    }
                ]
            }
        },
        "channels": [],
        "groups": [],
        "ims": [
            "D0L4B9P0Q"
        ],
        "has_rich_preview": false
    }
}

Uploading a file with the content parameter creates an editable text/plain file by default

{
    "ok": true,
    "file": {
        "id": "F0TD0GUTS",
        "created": 1532294750,
        "timestamp": 1532294750,
        "name": "-.txt",
        "title": "Untitled",
        "mimetype": "text/plain",
        "filetype": "text",
        "pretty_type": "Plain Text",
        "user": "U0L4B9NSU",
        "editable": true,
        "size": 11,
        "mode": "snippet",
        "is_external": false,
        "external_type": "",
        "is_public": true,
        "public_url_shared": false,
        "display_as_bot": false,
        "username": "",
        "url_private": "https://.../.txt",
        "url_private_download": "https://...download/-.txt",
        "permalink": "https://.../.txt",
        "permalink_public": "https://.../.txt",
        "edit_link": "https://.../.txt/edit",
        "preview": "launch plan",
        "preview_highlight": "<div class=\"CodeMirror cm-s-default CodeMirrorServer\" oncopy=\"if(event.clipboardData){event.clipboardData.setData('text/plain',window.getSelection().toString().replace(/\\u200b/g,''));event.preventDefault();event.stopPropagation();}\">\n<div class=\"CodeMirror-code\">\n<div><pre>launch plan</pre></div>\n</div>\n</div>\n",
        "lines": 1,
        "lines_more": 0,
        "preview_is_truncated": false,
        "comments_count": 0,
        "is_starred": false,
        "shares": {
            "public": {
                "C061EG9SL": [
                    {
                        "reply_users": [],
                        "reply_users_count": 0,
                        "reply_count": 0,
                        "ts": "1532294750.000001",
                        "channel_name": "general",
                        "team_id": "T061EG9R6"
                    }
                ]
            }
        },
        "channels": [
            "C061EG9SL"
        ],
        "groups": [],
        "ims": [],
        "has_rich_preview": false
    }
}

Typical error response

{
    "ok": false,
    "error": "invalid_auth"
}

Examples

Upload "dramacat.gif" from the current directory and share it in two channels, using multipart/form-data:

curl -F file=@dramacat.gif -F "initial_comment=Shakes the cat" -F channels=C024BE91L,D032AC32T -H "Authorization: Bearer xoxa-xxxxxxxxx-xxxx" https://slack.com/api/files.upload

Create an editable text file containing the text "launch plan":

curl -F "content=launch plan" -H "Authorization: Bearer xoxb-xxxxxxxxx-xxxx" https://slack.com/api/files.upload

Upload another image to an existing message thread:

curl -F file=@drworm.gif -F "initial_comment=I play the drums." -F channels=C024BE91L -F thread_ts=1532293503.000001 -H "Authorization: Bearer xoxp-xxxxxxxxx-xxxx" https://slack.com/api/files.upload

Errors

This table lists the expected errors that this method could return. However, other errors can be returned in the case where the service is down or other unexpected factors affect processing. Callers should always check the value of the ok params in the response.

Error	Description
`posting_to_general_channel_denied`	An admin has restricted posting to the #general channel.
`invalid_channel`	One or more channels supplied are invalid
`not_authed`	No authentication token provided.
`invalid_auth`	Some aspect of authentication cannot be validated. Either the provided token is invalid or the request originates from an IP address disallowed from making the request.
`account_inactive`	Authentication token is for a deleted user or workspace.
`token_revoked`	Authentication token is for a deleted user or workspace or the app has been removed.
`no_permission`	The workspace token used in this request does not have the permissions necessary to complete the request. Make sure your app is a member of the conversation it's attempting to post a message to.
`org_login_required`	The workspace is undergoing an enterprise migration and will not be available until migration is complete.
`ekm_access_denied`	Administrators have suspended the ability to post a message.
`missing_scope`	The token used is not granted the specific scope permissions required to complete this request.
`not_allowed_token_type`	The token type used in this request is not allowed.
`invalid_arguments`	The method was either called with invalid arguments or some detail about the arguments passed are invalid, which is more likely when using complex arguments like blocks or attachments.
`invalid_arg_name`	The method was passed an argument whose name falls outside the bounds of accepted or expected values. This includes very long names and names with non-alphanumeric characters other than `_`. If you get this error, it is typically an indication that you have made a very malformed API call.
`invalid_charset`	The method was called via a `POST` request, but the `charset` specified in the `Content-Type` header was invalid. Valid charset names are: `utf-8` `iso-8859-1`.
`invalid_form_data`	The method was called via a `POST` request with `Content-Type` `application/x-www-form-urlencoded` or `multipart/form-data`, but the form data was either missing or syntactically invalid.
`invalid_post_type`	The method was called via a `POST` request, but the specified `Content-Type` was invalid. Valid types are: `application/json` `application/x-www-form-urlencoded` `multipart/form-data` `text/plain`.
`missing_post_type`	The method was called via a `POST` request and included a data payload, but the request did not include a `Content-Type` header.
`team_added_to_org`	The workspace associated with your request is currently undergoing migration to an Enterprise Organization. Web API and other platform operations will be intermittently unavailable until the transition is complete.
`ratelimited`	The request has been ratelimited. Refer to the `Retry-After` header for when to retry the request.
`request_timeout`	The method was called via a `POST` request, but the `POST` data was either missing or truncated.
`service_unavailable`	The service is temporarily unavailable
`fatal_error`	The server could not complete your operation(s) without encountering a catastrophic error. It's possible some aspect of the operation succeeded before the error was raised.
`internal_error`	The server could not complete your operation(s) without encountering an error, likely due to a transient issue on our end. It's possible some aspect of the operation succeeded before the error was raised.

Warnings

This table lists the expected warnings that this method will return. However, other warnings can be returned in the case where the service is experiencing unexpected trouble.

Warning	Description
`missing_charset`	The method was called via a `POST` request, and recommended practice for the specified `Content-Type` is to include a `charset` parameter. However, no `charset` was present. Specifically, non-form-data content types (e.g. `text/plain`) are the ones for which `charset` is recommended.
`superfluous_charset`	The method was called via a `POST` request, and the specified `Content-Type` is not defined to understand the `charset` parameter. However, `charset` was in fact present. Specifically, form-data content types (e.g. `multipart/form-data`) are the ones for which `charset` is superfluous.

Sample code

Bolt for JavaScript is a foundational framework that makes it easier to build Slack apps with the platform's latest features.

Calling files.upload with Bolt for JavaScript

Hide code to initialize app
// Require the Bolt for JavaScript package (github.com/slackapi/bolt)
const { App, LogLevel } = require("@slack/bolt");

const app = new App({
  token: "xoxb-your-token",
  signingSecret: "your-signing-secret",
  // LogLevel can be imported and used to make debugging simpler
  logLevel: LogLevel.DEBUG
});
Show code to initialize app
// Listen for a /testUpload slash command
// Slash commands require the commands scope
app.command("/testUpload", async ({ payload, ack, context }) => {
  // Calling ack() acknowledges the request coming from Slack
  ack();
  
  // The name of the file you're going to upload
  const fileName = "myFileName.gif";
  
  try {
    // Call the files.upload method using the built-in WebClient
    const result = await app.client.files.upload({
      // The token you used to initialize your app is stored in the `context` object
      token: context.botToken,
      channels: payload.channel_id,
      initial_comment: "Here\'s my file :smile:",
      // Include your filename in a ReadStream here
      file: createReadStream(fileName)
    });

    console.log(result);
  }
  catch (error) {
    console.error(error);
  }
});
Hide code to run app
(async () => {
  // Start your app
  await app.start(process.env.PORT || 3000);

  console.log("⚡️ Bolt app is running!");
})();
Show code to run app

New to Bolt? Read our guide to Getting Started with Bolt for Javascript.

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