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// slack2html
// by @levelsio
// Slack lets you export the chat logs (back to the first messages!), even if
// you are a free user (and have a 10,000 user limit)
// This is pretty useful for big chat groups (like mine, #nomads), where you
// do wanna see the logs, but can't see them within Slack
// Problem is that Slack exports it as JSON files, which is a bit unusable,
// so this script makes it into actual HTML files that look like Slack chats
// Run this script inside the directory of an extracted (!) Slack export zip
// e.g. "/tmp/#nomads Slack export Aug 25 2015" like this:
// MacBook-Pro:#nomads Slack export Aug 25 2015 mbp$ php slack2html.php
// It will then make two dirs:
// /slack2html/json
// /slack2html/html
// In the JSON dir it will put each channels chat log combined from all the
// daily logs that Slack outputs (e.g. /channel/2014-11-26.json)
// In the HTML dir it will generate HTML files with Slack's typical styling.
// It will also create an index.html that shows all channels
// Let me know any bugs by tweeting me @levelsio
// Hope this helps!
// Pieter @levelsio
ini_set('memory_limit', '1024M');
// <config>
* {
body {
.messages {
.messages img {
.messages .time {
.messages .username {
.messages .message {
width:calc(100% - 3em);
.messages .message .msg {
// </config>
// <compile daily logs into single channel logs>
if(!is_dir($baseDir)) mkdir($baseDir);
if(!is_dir($jsonDir)) mkdir($jsonDir);
foreach($files as $channel) {
if($channel=='.' || $channel=='..') continue;
if(is_dir($channel)) {
if(file_exists($channelJsonFile)) {
echo "JSON already exists ".$channelJsonFile."\n";
echo '====='."\n";
echo 'Combining JSON files for #'.$channel."\n";
echo '====='."\n";
foreach($dates as $date) {
if(!is_dir($date)) {
echo '.';
if(empty($messages)) continue;
foreach($messages as $message) {
echo "\n";
echo number_format(count($chats)).' messages exported to '.$channelJsonFile."\n";
// </compile daily logs into single channel logs>
// <load users file>
foreach($users as $user) {
// </load users file>
// <load channels file>
foreach($channels as $channel) {
// </load channels file>
// <generate html from channel logs>
if(!is_dir($htmlDir)) mkdir($htmlDir);
foreach($channels as $channel) {
if($channel=='.' || $channel=='..') continue;
if(is_dir($channel)) continue;
if($message['ts']>$mostRecentChannelTimestamp) {
if(file_exists($channelHtmlFile)) {
echo "HTML already exists ".$channelJsonFile."\n";
echo '====='."\n";
echo 'Generating HTML for #'.$channelName."\n";
echo '====='."\n";
if(empty($messages)) continue;
$htmlMessages='<html><body><style>'.$stylesheet.'</style><div class="messages">';
foreach($messages as $message) {
if(empty($message)) continue;
if(empty($message['text'])) continue;
echo '.';
// change <@U38A3DE9> into levelsio
if(stripos($message['text'],'<@')!==false) {
foreach($usersInMessage as $userInMessage) {
if(empty($username)) {
// change <#U38A3DE9> into #_chiang-mai
if(stripos($message['text'],'<#')!==false) {
foreach($channelsInMessage as $channelInMessage) {
if(empty($username)) {
if(!empty($username)) {
// change <http://url> into link
if(stripos($message['text'],'<http')!==false) {
foreach($linksInMessage as $linkInMessage) {
$message['text']=str_replace('<http'.$linkTotalInBrackets.'>','<a href="http'.$linkInMessage.'">http'.$linkInMessage.'</a>',$message['text']);
// change @levelsio has joined the channel into
// @levelsio\n has joined #channel
if(stripos($message['text'],'has joined the channel')!==false) {
$message['text']=str_replace('the channel','#'.$channelName,$message['text']);
$message['text']=str_replace('@'.$usersById[$message['user']]['name'].' ','',$message['text']);
$htmlMessage.='<div><img src="'.$usersById[$message['user']]['profile']['image_72'].'" /><div class="message"><div class="username">'.$usersById[$message['user']]['name'].'</div><div class="time">'.date('Y-m-d H:i',$message['ts']).'</div><div class="msg">'.$message['text']."</div></div></div><br/>\n";
echo "\n";
// </generate html from channel logs>
// <make index html>
$html='<html><body><style>'.$stylesheet.'</style><div class="messages">';
foreach($mostRecentChannelTimestamps as $channel => $timestamp) {
$html.='<a href="./'.$channel.'.html">#'.$channel.'</a> '.date('Y-m-d H:i',$timestamp).'<br/>'."\n";
// </make index html>
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snikch commented Aug 25, 2016

@lukcha The reason for the incorrect characters is due to the line $message['text']=utf8_decode($message['text']);. This can be removed if you want your output files encoded as UTF-8 (which most people will want to do). If you open the files directly after this, you may notice other funny characters showing, however this is because the browser isn't displaying in UTF-8. You can force it to UTF-8 encoding in chrome from the View > Encoding menu.


If you're taking the html and pasting it into a website then if that website itself uses utf-8 encoding, for example, then you won't have a problem.

Alternatively anyone using this script and wanting the files to work with UTF-8, you can change the line $htmlMessages='<html><body><style>'.$stylesheet.'</style><div class="messages">'; to $htmlMessages='<html><head><meta charset="UTF-8"></head><body><style>'.$stylesheet.'</style><div class="messages">';. The page will now correctly render the UTF-8 content.

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xinmeng1 commented Aug 31, 2016

Working on the Fedora24, the instruction is as follow:

  1. install php: sudo dnf install php
  2. install php-mbstring: sudo dnf install php-mbstring
  3. install php-xml: sudo dnf install php-xml
  4. modify this file first line <? to <?php
  5. extract the to folder /your-team-name
  6. copy the the modified file to this folder
  7. run php slack2html.php
  8. you will find a new folder slack2html in the parent directory of the /your-team-name
  9. open the html in the /html folder

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Frost212 commented Sep 3, 2016

Is it possible to use this to instead covert the json to Plain text files? (I.e, merge them into the single json file as in part 1 of the script, then parse all of the user/channel ID's to their actual names, and into a plain text file so it can be logged and searched in a database?) Instead of making them into Html images?

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abinashmohanty commented Oct 19, 2016

@levelsio this is superb! And it worked like a charm. Thanks a lot!

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abinashmohanty commented Oct 19, 2016

I have a question! How can I sync all slack history in real time using slack's API method in stead of downloading its backups manually every time?

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ameet-padte commented Oct 23, 2016

Is there a way to export the chats in full "Slack view" (i.e. pasted link unfurls, Giphys, pasted images, etc.)?

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bjt1t2t3 commented Nov 8, 2016

Found this through a Google search and would like to be able to use this for our Slack team. I've downloaded the Slack archive, but am not a programmer and really do not understand how to proceed. I have no idea how to run a script inside a directory, as the instructions state.

Are there any step-by-step instructions available on how to use this for someone without php or programming skills?

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Zseselja commented Nov 17, 2016

Thanks mate! Works great!

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elina-codes commented Dec 18, 2016

@natsandman-rav I'm having the same issue. Did you find a solution?

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humor4fun commented Jan 25, 2017

@github3332 My script uses a derivative work of this script. Currently there exists another issue though, where line 53 of this php tool continues to fail.

root@kali:~/Desktop# php slack-json-2-html.php 
PHP Fatal error:  Uncaught Error: Call to undefined function mb_internal_encoding() in /root/Desktop/slack-json-2-html.php:53
Stack trace:
#0 {main}
  thrown in /root/Desktop/slack-json-2-html.php on line 53

Can be fixed by installing the php-mbstring package for your os.

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humor4fun commented Jan 26, 2017

Usernames aren't pulled in to the html.

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0600Zulu commented Mar 4, 2017

Is there a way to add a feature that includes threaded messages? This tool works fine even since the threaded message update, but it sorts threaded messages by time in the whole channel vs. with the original message.

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ghost commented Mar 14, 2017

Does that work for Windows?

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johnwake commented Mar 20, 2017

Great post and works like a charm. Well done Sir! 👍

I had a memory problem when running is on my mac. The error was:
Fatal error: Allowed memory size of 1073741824 bytes exhausted (tried to allocate 32 bytes) in /Users/c2349192/workspace/slack-archives/Team Awesome Slack export Mar 20 2017/slack2html.php on line 186

I increased the memory limit on line 50 and it completed with no problems.

ini_set('memory_limit;, '2048M'); 

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ghost commented Sep 1, 2017

For windows:,

  1. Install Wamp Server (
  2. In the install directory, find the location of php.exe. You'll need reference this path later. (i.e "C:\Wamp64\bin\php\php7.0.0\php.exe" )
  3. Create a folder on your desktop called 'Slack'. Download the Slack message history zip. Extract to 'Slack' folder. You'll need to reference this path later. (i.e "C:\Users\YourName\Desktop\Slack\Slack_Project_Name Slack export Sep 1 2017"
  4. Download the file from this repository (gistfile1.txt) and store it in the same folder as Step 3.
  5. Rename gistFile1.txt to GenerateSlackReport.php
  6. Open the command prompt, (Start->Run->Cmd) (You may need to find this program and right click to Run as Administrator)
  7. Change directory to the location of Step 3. (ie. "cd C:/Users/YourName/Desktop/Slack/Slack_Project_Name Slack export Sep 1 2017"
  8. In the command prompt, execute this command, replacing your php.exe location with your own: "C:\Wamp64\bin\php\php7.0.0\php.exe" GenerateReport.php

Reports are generated now. Hope this helps.

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mario6097 commented Sep 9, 2017


As far as I see, this script does not create code to see pictures on the local page, it renders only a link to the slack url of the picture, doesn't it?
Indeed, it would be nice to have it be able to download pictures in a local folder.
Any chance to see a improved code (which is indeed very very useful)
Thanks Cheers

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droberin commented Feb 9, 2018

Hey, as I don't want to install PHP on my system I just used a basic PHP docker image.


  • Docker Engine (docker-ce is great)


  • Create a temporary dir
mkdir $HOME/slack2html/
  • Decompress zip file with messages in that temporary folder
cd $HOME/slack2html/ ; unzip
  • Download gist file as slack2html.php
wget -O slack2html.php
  • Run Docker Container with PHP
docker run -ti --rm -v $HOME/slack2html:/mnt/slack_data \
 -v $HOME/slack2html_output:/mnt/slack2html/ \
 php:7 bash -c 'cd /mnt/slack_data && php slack2html.php'
  • Check result at output folder
ls -al $HOME/slack2html_output/html/
firefox $HOME/slack2html_output/html/index.html

Clean after yourself

If you are not a PHP-docker-image user, you may wanna remove that previously downloaded image that takes (at this time) ~350MiB of storage.

docker rmi php:7


  __ ___      _____  ___  ___  _ __ ___   ___ _ __   ___  ___ ___
 / _` \ \ /\ / / _ \/ __|/ _ \| '_ ` _ \ / _ \ '_ \ / _ \/ __/ __|
| (_| |\ V  V /  __/\__ \ (_) | | | | | |  __/ | | |  __/\__ \__ \
 \__,_| \_/\_/ \___||___/\___/|_| |_| |_|\___|_| |_|\___||___/___/

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droberin commented Feb 9, 2018

@mario6097, you may wanna check my gist for replacing those avatars with locally downloaded avatars.
It's written in python as it's been years since I don't code in PHP.

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yani1shu commented Jun 19, 2018

Im noticing that this script skips messages where "text": null. I have many messages where this is the case, usually from a bot. There is message information in the attachment though. Would it be possible to have these messages included?

also, would it be possible to keep each day in its own file rather than combining them? a single file for a whole channel can be very unwieldy

Great script altogether.

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pprindeville commented Jul 28, 2018

Try changing <? to <?php

@levelsio I also found I needed to insert the top line as:

#!/usr/bin/env php


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ememdev commented Oct 26, 2018

👍 Thank you!

Also needed to add 'php' to the top line, and install php-mbstring to resolve that mb_internal_encoding() error mentioned earlier

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iversond commented Nov 5, 2018

Very nice! This was extremely helpful. Thanks for sharing it!

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lsmith77 commented Dec 28, 2018

sadly doesn’t seem to handle emoji reactions .. anyone implemented this already?

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yani1shu commented May 23, 2019

Would it be possible to have it maintain the one day per channel structure that Slack provides rather than combining multiple days?

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robhawkins commented Jul 14, 2019

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davisgoodman commented Apr 11, 2020

I used the slack-export which worked great but slack-export-viewer keeps giving me these errors:

MacBook-Pro-17:slack-export-master davis$ slack-export-viewer -p 80 -I 192.168.x.x --debug -z
WARNING: DEBUG MODE IS ENABLED! extracting to /var/folders/p1/p83kf_2n3l37p7yxgmn3113m0000gn/T/_slackviewer/4d730203a1403212f1458d8709540e73a056eec3... extracted to /var/folders/p1/p83kf_2n3l37p7yxgmn3113m0000gn/T/_slackviewer/4d730203a1403212f1458d8709540e73a056eec3
Traceback (most recent call last):
File "/usr/local/bin/slack-export-viewer", line 8, in
File "/usr/local/lib/python3.7/site-packages/click/", line 829, in call
return self.main(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/click/", line 782, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python3.7/site-packages/click/", line 1066, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/lib/python3.7/site-packages/click/", line 610, in invoke
return callback(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/slackviewer/", line 61, in main
configure_app(app, archive, channels, no_sidebar, no_external_references, debug)
File "/usr/local/lib/python3.7/site-packages/slackviewer/", line 25, in configure_app
top.groups = reader.compile_groups()
File "/usr/local/lib/python3.7/site-packages/slackviewer/", line 42, in compile_groups
return self._create_messages(group_names, group_data)
File "/usr/local/lib/python3.7/site-packages/slackviewer/", line 176, in _create_messages
chats = self._build_threads(chats)
File "/usr/local/lib/python3.7/site-packages/slackviewer/", line 199, in _build_threads
for reply in message._message['replies']:
KeyError: 'replies'

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christianpbrink commented Apr 21, 2020

I keep getting same KeyError: 'replies'

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danielmbond commented Jun 12, 2020

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jmcuylerCPH commented Jul 24, 2020

Here's a challenge - get the PHP script to include bot messages as well. The idea being to have a readable account of alerts dumped into a channel by a bot along with all user posts in response. Would love to see this.

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Lene20 commented Nov 10, 2020

Thank you for the instructions! May somebody please share an example of how the HTML file looks like after the conversion?

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