Slack Ruby Client

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A Ruby client for the Slack Web and RealTime Messaging APIs. Comes with a handy command-line client, too.

Useful to Me?

  • This piece of the puzzle will help you send messages to Slack via the Web API and send and receive messages via the Real Time API.
  • If you're trying to respond to slash commands, just write a basic web application and use this library to call the Slack Web API.
  • If you're trying to build a Real Time bot, use slack-ruby-bot, which uses this library.
  • If you're trying to roll out a full service with Slack button integration to multiple teams, check out slack-bot-server, which is built on top of slack-ruby-bot, which uses this library.

Stable Release

You're reading the documentation for the next release of slack-ruby-client. Please see the documentation for the last stable release, v0.6.0 unless you're integrating with HEAD. See UPGRADING when upgrading from an older version.


Add to Gemfile.

gem 'slack-ruby-client'

If you're going to be using the RealTime client, add either eventmachine and faye-websocket or celluloid-io. See below for more information about concurrency.

gem 'eventmachine'
gem 'faye-websocket'

Run bundle install.


Create a New Bot Integration

This is something done in Slack, under integrations. Create a new bot, and note its API token.

Use the API Token

Slack.configure do |config|
  config.token = ENV['SLACK_API_TOKEN']

This sets a global default token. You can also pass a token into the initializer of both Slack::Web::Client and Slack::RealTime::Client or configure those separately via Slack::Web::Config.configure and Slack::RealTime::Config.configure. The instance token will be used over the client type token over the global default.

Web Client

The Slack Web API allows you to build applications that interact with Slack.

Test Auth

client =

Send Messages

Send messages with chat_PostMessage.

client.chat_postMessage(channel: '#general', text: 'Hello World', as_user: true)

See a fully working example in examples/hi_web.

List Channels

List channels with channels_list.

channels = client.channels_list.channels

general_channel = channels.detect { |c| == 'general' }

Upload a File

Upload a file with files_upload.

  channels: '#general',
  as_user: true,
  file:'/path/to/avatar.jpg', 'image/jpeg'),
  title: 'My Avatar',
  filename: 'avatar.jpg',
  initial_comment: 'Attached a selfie.'

Get Channel Info

You can use a channel ID or name (prefixed with #) in all functions that take a :channel argument. Lookup by name is not supported by the Slack API and the channels_id method called invokes channels_list in order to locate the channel ID.

client.channels_info(channel: 'C04KB5X4D') # calls channels_info
client.channels_info(channel: '#general') # calls channels_list followed by channels_info

Get User Info

You can use a user ID or name (prefixed with @) in all functions that take a :user argument. Lookup by name is not supported by the Slack API and the users_id method called invokes users_list in order to locate the user ID.

client.users_info(user: 'U092BDCLV') # calls users_info
client.users_info(user: '@dblock') # calls users_list followed by users_info

Search for a User

Constructs an in-memory index of users and searches it. If you want to use this functionality, add the picky gem to your project's Gemfile.

client.users_search(user: 'dblock')


Refer to the Slack Web API Method Reference for the list of all available functions.

Web Client Options

You can configure the Web client either globally or via the initializer.

Slack::Web::Client.config do |config|
  config.user_agent = 'Slack Ruby Client/1.0'
client = 'Slack Ruby Client/1.0')

The following settings are supported.

setting description
token Slack API token.
user_agent User-agent, defaults to Slack Ruby Client/version.
proxy Optional HTTP proxy.
ca_path Optional SSL certificates path.
ca_file Optional SSL certificates file.
endpoint Slack endpoint, default is
logger Optional Logger instance that logs HTTP requests.

RealTime Client

The Real Time Messaging API is a WebSocket-based API that allows you to receive events from Slack in real time and send messages as user.

client =

client.on :hello do
  puts "Successfully connected, welcome '#{}' to the '#{}' team at https://#{}"

client.on :message do |data|
  case data.text
  when 'bot hi' then
    client.message channel:, text: "Hi <@#{data.user}>!"
  when /^bot/ then
    client.message channel:, text: "Sorry <@#{data.user}>, what?"


You can send typing indicators with typing.

client.typing channel:

You can send a ping with ping.

By default, the RealTime client exposes and maintains a local store with the properties of rtm.start upon a successful connection.

property description
url A WebSocket Message Server URL.
self The authenticated bot user.
team Details on the authenticated user's team.
users A hash of user objects by user ID.
channels A hash of channel objects, one for every channel visible to the authenticated user.
groups A hash of group objects, one for every group the authenticated user is in.
ims A hash of IM objects, one for every direct message channel visible to the authenticated user.
bots Details of the integrations set up on this team.

It also tracks changes, such as users being renamed, added or deleted, therefore client.users is always up-to-date.

Tracking with a local store can be disabled with nil)

You can configure the RealTime client either globally or via the initializer.

Slack::RealTime::Client.config do |config|
  config.websocket_ping = 42
client = 42)

The following settings are supported.

setting description
token Slack API token.
websocket_ping The number of seconds that indicates how often the WebSocket should send ping frames, default is 30.
websocket_proxy Connect via proxy, include :origin and :headers.
store_class Local store class name, default is an in-memory Slack::RealTime::Store.
start_options Options to pass into rtm.start, default is {}.

Note that the RealTime client uses a Web client to obtain the WebSocket URL via rtm.start, configure Web client options via Slack::Web::Client.configure as described above.

See a fully working example in examples/hi_real_time.

Combining RealTime and Web Clients

Since the Web client is used to obtain the RealTime client's WebSocket URL, you can continue using the Web client in combination with the RealTime client.

client =

client.on :message do |data|
  case data.text
  when 'bot hi' then
    client.web_client.chat_postMessage channel:, text: "Hi <@#{data.user}>!"
  when /^bot/ then
    client.web_client.chat_postMessage channel:, text: "Sorry <@#{data.user}>, what?"


See a fullly working example in examples/hi_real_time_and_web.


Slack::RealTime::Client needs help from a concurrency library and supports Faye::WebSocket with Eventmachine and Celluloid. It will auto-detect one or the other depending on the gems in your Gemfile, but you can also set concurrency explicitly.

Slack::RealTime.configure do |config|
  config.concurrency = Slack::RealTime::Concurrency::Eventmachine

Use client.start_async instead of client.start! if you don't want the library to control the event run loop, such as when integrating into other applications that already use Eventmachine or Celluloid. A good example of such application is slack-bot-server.

client = do

See a fully working example in examples/hi_real_time_async.

Faye::Websocket with Eventmachine

Add the following to your Gemfile.

gem 'faye-websocket'

Add the following to your Gemfile.

gem 'celluloid-io'

Message Parsing

All text in Slack uses the same system of escaping: chat messages, direct messages, file comments, etc. Use Slack::Messages::Formatting to unescape incoming messages. This comes handy, for example, you want to treat all input to a real time bot as plain text.

Slack::Messages::Formatting.unescape('Hello &amp; &lt;world&gt;'))
  # => 'Hello & <world>'
Slack::Messages::Formatting.unescape('Hey <@U024BE7LH|bob>, did you see my file?'))
  # => 'Hey @bob, did you see my file?'
Slack::Messages::Formatting.unescape('Hey <@U02BEFY4U>'))
  # => 'Hey @U02BEFY4U'
Slack::Messages::Formatting.unescape('This message contains a URL <>'))
  # => 'This message contains a URL'
Slack::Messages::Formatting.unescape('So does this one: <|>'))
  # => 'So does this one:'
Slack::Messages::Formatting.unescape('<mailto:[email protected]|Bob>'))
  # => 'Bob'
Slack::Messages::Formatting.unescape('Hello <@U123|bob>, say hi to <!everyone> in <#C1234|general>'))
  # => 'Hello @bob, say hi to @everyone in #general'
Slack::Messages::Formatting.unescape('Hello <@U123|bob> &gt; file.txt'))
  # => 'Hello @bob > file.txt'
  # => '"hello"'
  # => "'hello'"

Command-Line Client

The slack command-line client returns JSON data from the Slack API.

Authenticate with Slack

$ slack --slack-api-token=[token] auth test

Send a Message

export SLACK_API_TOKEN=...
$ slack chat postMessage --text="hello world" --channel="#general"
{"ok":true,"channel":"...","ts":"...","message":{"text":"hello world","username":"bot","type":"message","subtype":"bot_message","ts":"..."}}

Get Channel Id

$ slack channels id --channel=#general

Get Channel Info

$ slack channels info --channel=#general
{"ok":true,"channel":{"id":"C04KB5X4D","name":"general", ...}}

List Users

Combine with jq, a command-line JSON parser.

$ slack users list | jq '.members | map({(.id): .name})'
    "U04KB5WQR": "dblock"
    "U07518DTL": "rubybot"

See slack help for a complete command-line reference.


This gem is based on slack-ruby-gem, but it more clearly separates the Web and RTM APIs, is more thoroughly tested and is in active development.



Copyright (c) 2015-2016, Daniel Doubrovkine, Artsy and Contributors.

This project is licensed under the MIT License.