Send, reply, edit and react to Slack messages

slackcli messages sends, edits, reacts to, and drafts messages.

Every subcommand accepts --workspace <id|name>.

messages send

# To a channel
slackcli messages send --recipient-id=C1234567890 --message="Hello team!"

# To a person — the DM is opened for you
slackcli messages send --recipient-id=U9876543210 --message="Hey there!"

# As a thread reply
slackcli messages send --recipient-id=C1234567890 --thread-ts=1234567890.123456 --message="Great idea!"

# Reply in the thread a link points at
slackcli messages send --permalink="https://myteam.slack.com/archives/C1234567890/p1234567890123456" --message="Great idea!"

# With a file attached
slackcli messages send --recipient-id=C1234567890 --message="Here is the file" --file=./report.pdf

# Message text from a file
slackcli messages send --recipient-id=C1234567890 --message-file=./release-notes.md

Option	Purpose
--recipient-id <id>	Channel ID, user ID, or Slack URL
--message <text>	Message text. Required unless --message-file is given
--message-file <path>	Read the message text from a UTF-8 file; cannot be combined with --message
--thread-ts <ts>	Post as a reply in this thread
--permalink <url>	Replaces --recipient-id and --thread-ts
--file <path>	Attach a file; the message text becomes the comment
--blocks <json|@file>	Block Kit JSON array; cannot be combined with --file
--json	Print the delivered message as JSON instead of the human line

A --recipient-id starting with U opens a DM first. File uploads need upload permission in the workspace — files:write for standard tokens. Uploads go through Slack’s external-upload flow; empty files, directories, and missing paths are rejected before anything is sent.

On success the message timestamp is printed — capture it if you want to edit or react to the message later, or use --json to get it as structured data.

Message text from a file (--message-file)

--message-file reads the message body from a UTF-8 file instead of an argument, which avoids quoting and shell-escaping a long or multi-line message:

slackcli messages send --recipient-id=C1234567890 --message-file=./release-notes.md

The file’s contents are sent exactly as --message would send them, mrkdwn included. --message and --message-file are mutually exclusive, and exactly one of them is required. A missing path, or a file that is empty or only whitespace, is an error raised before anything is sent.

JSON output (--json)

--json replaces the human success line with a single object on stdout, so a script can keep the message’s identity for a follow-up call:

slackcli messages send --recipient-id=C1234567890 --message="Deploying…" --json

{
  "channel_id": "C1234567890",
  "ts": "1234567890.123456",
  "permalink": "https://myteam.slack.com/archives/C1234567890/p1234567890123456"
}

permalink is looked up separately with chat.getPermalink after the message is delivered. If that lookup fails — a token without the scope, say — the key is omitted rather than emitted as null; the send itself still succeeded. Test for the key rather than assuming it.

With --file, the upload flow returns the attached file rather than a message timestamp, so that branch emits channel_id and file_id only.

Errors are unaffected by --json: they still go to stderr with exit code 1, and nothing is written to stdout.

Text formatting

Message text is sent with Slack’s parse=none, so Slack mrkdwn works as you write it: *bold*, _italic_, ~strike~, `code`, triple-backtick blocks, and links as <https://example.com|label>. Slack has no [text](https://github.com/shaharia-lab/slackcli/blob/main/docs/user-guide/url) link syntax and no # headings in plain message text — use --blocks with a markdown block if you want those.

Block Kit (--blocks)

--blocks takes a JSON array of Block Kit blocks, inline or loaded from a file with --blocks=@blocks.json. It works with both auth types. The required --message text is still used as the notification and accessibility fallback.

Native markdown blocks take standard Markdown rather than Slack mrkdwn, which buys you headings, task lists, syntax-highlighted code fences, and Markdown tables:

slackcli messages send \
  --recipient-id=C1234567890 \
  --message="Release notes" \
  --blocks='[{"type":"markdown","text":"# Release notes\n\n- [x] Build\n- [ ] Deploy\n\nSee the [runbook](https://example.com/runbook)."}]'

Native table blocks render a real table instead of a code block:

slackcli messages send \
  --recipient-id=C1234567890 \
  --message="Project status table" \
  --blocks='[
    {
      "type": "table",
      "column_settings": [{"is_wrapped": true}, {"align": "right"}],
      "rows": [
        [
          {"type": "rich_text", "elements": [{"type": "rich_text_section", "elements": [{"type": "text", "text": "Project", "style": {"bold": true}}]}]},
          {"type": "rich_text", "elements": [{"type": "rich_text_section", "elements": [{"type": "text", "text": "Status", "style": {"bold": true}}]}]}
        ],
        [
          {"type": "rich_text", "elements": [{"type": "rich_text_section", "elements": [{"type": "link", "text": "SlackCLI", "url": "https://github.com/shaharia-lab/slackcli"}]}]},
          {"type": "raw_text", "text": "Ready"}
        ]
      ]
    }
  ]'

The JSON is validated before the request: it must be an array, and every element must be an object with a non-empty string type. Errors name the offending index.

messages edit

slackcli messages edit --channel-id=C1234567890 --timestamp=1234567890.123456 --message="Corrected message"
slackcli messages edit --permalink="https://myteam.slack.com/archives/C1234567890/p1234567890123456" --message="Corrected message"

Only messages posted by the authenticated user or app can be edited; ephemeral messages cannot. Links survive an edit — SlackCLI sends parse=none explicitly, because chat.update would otherwise default to client and escape <url|label> markup.

--json prints the edited message’s identity instead of the human line. There is no permalink lookup here: the caller already had the message’s location in order to edit it.

{
  "channel_id": "C1234567890",
  "ts": "1234567890.123456"
}

--message-file works here exactly as it does on messages send — the new body comes from a UTF-8 file, mutually exclusive with --message.

messages react

slackcli messages react --channel-id=C1234567890 --timestamp=1234567890.123456 --emoji=+1
slackcli messages react --permalink="https://myteam.slack.com/archives/C1234567890/p1234567890123456" --emoji=heart

--emoji takes the name without colons: +1/thumbsup 👍, heart ❤️, fire 🔥, eyes 👀, tada 🎉, rocket 🚀. Custom workspace emoji work too.

messages draft

slackcli messages draft --recipient-id=C1234567890 --message="Hello team!"

Creates an unsent draft in the Slack client — useful when you want a human to review and press send.

Browser auth only. Slack apps cannot create drafts; there is no public API for it. With a standard token the command fails with Draft creation requires browser authentication.

The text is converted from Slack mrkdwn into rich_text blocks so the draft opens in the composer already formatted. --message-file works here exactly as it does on messages send.

--json prints the draft’s identity. A draft is unsent, so it has no message timestamp and no permalink — the draft id is what a follow-up has to work with. thread_ts is present only when the draft is a threaded reply.

{
  "channel_id": "C1234567890",
  "draft_id": "1234567890.123456"
}

Related

• Slack links and timestamps — what --permalink accepts
• Scripting and JSON output — capturing timestamps in a script