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.

Arguments

Argument	Type	Description
`token`Required	token	Authentication token bearing required scopes. Tokens should be passed as an HTTP Authorization header or alternatively, as a POST parameter. Example`xxxx-xxxxxxxxx-xxxx`
`channels`	channels	Comma-separated list of channel names or IDs where the file will be shared. Example`C1234567890,C2345678901,C3456789012`
`content`	string	File contents via a POST variable. If omitting this parameter, you must provide a `file`. Example`...`
`file`	post_file	File contents via `multipart/form-data`. If omitting this parameter, you must submit `content`. Example`...`
`filename`	string	Filename of file. Example`foo.txt`
`filetype`	string	A file type identifier. Example`php`
`initial_comment`	string	The message text introducing the file in specified `channels`. Example`Best!`
`thread_ts`	timestamp	Provide another message's `ts` value to upload this file as a reply. Never use a reply's `ts` value; use its parent instead. Example`1234567890.123456`
`title`	string	Title of file. Example`My File`

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

Example responses

Common successful response

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
    }
}

Alternate response

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
    }
}

Common error response

Typical error response

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

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

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. The owner of the token used to upload the file must also be a member of any channel you wish to post to this way.

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.

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.

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
`file_uploads_disabled` [hidden]	Team Owner has requested that no users can upload files on this team.
`file_uploads_except_images_disabled` [hidden]	Team Owner has requested that only image files, but nothing else, can be uploaded on this team.
`file_upload_size_restricted` [hidden]	Team admin has set max limit on file size for uploaded files
`no_file` [hidden]	No file or filename was included.
`storage_limit_reached` [hidden]	Team is out of file storage space.
`not_in_channel`	Authenticated user is not in the channel.
`channel_not_found`	At least one of the values passed for `channels` was invalid.
`upload_error` [hidden]	upload error (generated)
`posting_to_channel_denied` [hidden]	posting to channel denied (generated)
`no_file_data` [hidden]	no file data (generated)
`slack_connect_file_upload_sharing_blocked`	Admin has disabled File uploads in all Slack Connect communications
`slack_connect_blocked_file_type`	File uploads with certain types are blocked in all Slack Connect communications
`malware_detected`	This file may contain a virus or other malware and can't be uploaded to Slack
`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 when using a `bot` token.
`token_revoked`	Authentication token is for a deleted user or workspace or the app has been removed when using a `user` token.
`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.
`method_deprecated`	The method has been deprecated.
`deprecated_endpoint`	The endpoint has been deprecated.
`two_factor_setup_required`	Two factor setup is required.
`enterprise_is_restricted`	The method cannot be called from an Enterprise.
`team_access_not_granted`	The token used is not granted the specific workspace access required to complete this request.
`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_array_arg`	The method was passed an array as an argument. Please only input valid strings.
`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.
`invalid_json` [hidden]	The method was called via a `POST` request with `Content-Type` `application/json`, but the body was not valid JSON.
`json_not_object` [hidden]	The method was called via a `POST` request a valid JSON body, but the JSON value was not an object.
`ratelimited`	The request has been ratelimited. Refer to the `Retry-After` header for when to retry the request.
`accesslimited`	Access to this method is limited on the current network
`request_timeout`	The method was called via a `POST` request, but the `POST` data was either missing or truncated.
`upgrade_required` [hidden]	The calling application needs to be upgraded.
`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.

API response

URL

POST body

Submit your arguments to see the API response

Calling files.upload

Java

JavaScript

Python

Java

import com.slack.api.bolt.App;
import com.slack.api.bolt.AppConfig;
import com.slack.api.bolt.jetty.SlackAppServer;
import com.slack.api.methods.SlackApiException;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;

public class FilesUpload {

    public static void main(String[] args) throws Exception {
        var config = new AppConfig();
        config.setSingleTeamBotToken(System.getenv("SLACK_BOT_TOKEN"));
        config.setSigningSecret(System.getenv("SLACK_SIGNING_SECRET"));
        var app = new App(config); // `new App()` does the same

        app.command("/testUpload", (req, ctx) -> {
            var logger = ctx.logger;
            try {
                var payload = req.getPayload();
                // The name of the file you're going to upload
                var filepath = "./myFileName.gif";
                // Call the files.upload method using the built-in WebClient
                var result = ctx.client().filesUpload(r -> r
                    // The token you used to initialize your app is stored in the `context` object
                    .token(ctx.getBotToken())
                    .channels(Arrays.asList(payload.getChannelId()))
                    .initialComment("Here's my file :smile:")
                    // Include your filename in a ReadStream here
                    .file(new File(filepath))
                );
                // Print result
                logger.info("result: {}", result);
            } catch (IOException | SlackApiException e) {
                logger.error("error: {}", e.getMessage(), e);
            }
            // Acknowledge incoming command event
            return ctx.ack();
        });

        var server = new SlackAppServer(app);
        server.start();
    }

}

JavaScript

Code to initialize Bolt app
// Require the Node Slack SDK package (github.com/slackapi/node-slack-sdk)
const { WebClient, LogLevel } = require("@slack/web-api");

// WebClient insantiates a client that can call API methods
// When using Bolt, you can use either `app.client` or the `client` passed to listeners.
const client = new WebClient("xoxb-your-token", {
  // LogLevel can be imported and used to make debugging simpler
  logLevel: LogLevel.DEBUG
});
// The name of the file you're going to upload
const fileName = "./myFileName.gif";
// ID of channel that you want to upload file to
const channelId = "C12345";

try {
  // Call the files.upload method using the WebClient
  const result = await client.files.upload({
    // channels can be a list of one to many strings
    channels: channelId,
    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);
}

Python

Code to initialize Bolt app
import logging
import os
# Import WebClient from Python SDK (github.com/slackapi/python-slack-sdk)
from slack_sdk import WebClient
from slack_sdk.errors import SlackApiError

# WebClient insantiates a client that can call API methods
# When using Bolt, you can use either `app.client` or the `client` passed to listeners.
client = WebClient(token=os.environ.get("SLACK_BOT_TOKEN"))
logger = logging.getLogger(__name__)
# The name of the file you're going to upload
file_name = "./myFileName.gif"
# ID of channel that you want to upload file to
channel_id = "C12345"

try:
    # Call the files.upload method using the WebClient
    # Uploading files requires the `files:write` scope
    result = client.files_upload(
        channels=channel_id,
        initial_comment="Here's my file :smile:",
        file=file_name,
    )
    # Log the result
    logger.info(result)

except SlackApiError as e:
    logger.error("Error uploading file: {}".format(e))

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