How to Save Slack, Discord & iMessage Conversations as PDFs on Mac

Chat messages feel permanent until they're not. Slack's free plan hides messages older than 90 days (Slack Help Center). Discord servers get deleted without warning. iMessage conversations are tied to your Apple devices and iCloud storage. Workplace Slack channels get archived when projects end. The conversation you need to reference — that important decision, that shared link, that debugging session — is gone.

These platforms weren't built for long-term archival. They're communication tools optimized for real-time conversation, not record-keeping. If you need a permanent, searchable record of a conversation, you need to save it yourself.

This guide covers archiving conversations from Slack, Discord, and iMessage as searchable PDFs on your Mac. The same approach works for any chat application.

TL;DR: Open the conversation, use automated Page Down scrolling to capture the chat history, export as a searchable PDF. For sensitive content, redact with Preview.app after export.

Why Chat Messages Disappear

Each platform has its own way of making your messages inaccessible:

Slack: The 90-Day Wall

Slack's free plan limits visible message history to 90 days. After that, older messages disappear from view. They're technically still on Slack's servers, but you can't see, search, or reference them. For many teams — especially open-source communities, small startups, and hobby groups — the free plan is all they use.

Even on paid plans, Slack workspaces can be decommissioned. When a company gets acquired, reorganizes, or a project ends, entire workspaces get deleted. Years of institutional knowledge, technical decisions, and documented conversations vanish.

Discord: Servers Disappear

Discord servers can be deleted by their owner at any time (Discord Support), taking every channel and message with them. Community servers shut down. Gaming guild servers go inactive. Study group servers get deleted after the semester ends. There's no warning and no recovery.

Individual users can also delete their messages retroactively, removing their side of conversations you might need.

iMessage: Device and Storage Dependent

iMessage conversations persist as long as your Apple ecosystem stays intact — same Apple ID, same iCloud account, sufficient iCloud storage. But device changes, iCloud storage limits, or accidentally deleting a conversation can wipe out years of messages. macOS Messages also doesn't include a built-in conversation export feature.

Capturing Slack Conversations

Slack's Mac app (or Slack in the browser) works well with window capture and scroll automation.

Step 1: Navigate to the Conversation

Open Slack and navigate to the channel or DM you want to archive. If you want to capture a specific date range, scroll to the starting point.

Tip for channels with lots of messages: Use Slack's "Jump to date" feature (click the channel name → click the date) to navigate to a specific point in the conversation history rather than scrolling manually.

Step 2: Set Up the Capture

Open Shotomatic:

• Capture mode: Window capture — select the Slack window
• Keypress: Page Down (press the key in the recorder)
• Interval: 800ms

Step 3: Capture the History

Scroll to the oldest message you want to capture. Start the capture. Shotomatic will capture the visible area, press Page Down to scroll forward in time, and repeat.

Important: Slack scrolls chronologically — oldest at top, newest at bottom. Page Down moves you forward in time. Start from the oldest message you want and capture forward to the present.

Stop when you reach the current messages or the end of the range you wanted.

Step 4: Export

Export as PDF. The conversation is now a permanent, searchable document — usernames, timestamps, messages, shared links, emoji reactions, and all. If you are deciding between formats, see the broader guide to exporting screenshots as PDF, JPG, PNG, or MP4.

Archiving Entire Slack Channels

For archiving an entire channel (before a workspace gets deleted, for example):

1. Jump to the very beginning of the channel
2. Set up window capture with Page Down at 800ms
3. Start capturing and let it run — this can take a while for active channels
4. Stop at the present

For channels with years of history, consider breaking the capture into chunks — one PDF per month or per quarter. This keeps file sizes manageable and makes it easier to find specific conversations later.

Slack Threads

Slack threads appear in a sidebar panel. To capture a thread:

1. Open the thread in the sidebar
2. Window capture the Slack window (the thread panel will be visible)
3. If the thread is long, use Page Down to scroll through it
4. Export as PDF

Capturing Discord Conversations

Discord's Mac app works similarly to Slack for capture purposes.

Channels and DMs

1. Open Discord and navigate to the channel or DM
2. Scroll to the starting point of what you want to capture
3. In Shotomatic, set up window capture with Page Down at 800ms
4. Capture through the conversation history
5. Export as PDF

Discord Server Archival

If you want to archive an entire Discord server (before it's deleted or you leave), you'll need to capture each channel individually:

1. Make a list of channels you want to archive
2. For each channel, scroll to the beginning, capture through to the end
3. Name each PDF: ServerName_ChannelName_Date.pdf

This is time-intensive for large servers, but it's the only way to preserve the content in a readable format. Discord's own data export gives you JSON files that require processing to read — screenshot PDFs give you the conversation as it actually looked.

Discord Forum Channels

Discord forum channels (the thread-based channels) work slightly differently:

1. Open the specific forum post/thread
2. Window capture with Page Down
3. Each forum thread becomes its own PDF

Handling Embeds and Attachments

Discord messages often include embedded images, link previews, code blocks, and file attachments. Screenshots capture all of these as they appear on screen. Code blocks with syntax highlighting are preserved visually. Attached files show as download buttons — the files themselves aren't captured, only their visual representation.

Capturing iMessage Conversations

iMessage (the Messages app on Mac) is a native macOS application, not a web app. Window capture works the same way.

Standard Conversations

1. Open Messages and select the conversation
2. Scroll to the beginning of the section you want to capture (hold Shift and scroll up, or use the scrollbar)
3. In Shotomatic, select window capture and choose the Messages window
4. Press Page Down in the key recorder with 600ms interval (Messages scrolls quickly since content is local)
5. Capture through the conversation
6. Export as PDF

iMessage Quirks

Scrolling to old messages takes time. iMessage loads older messages as you scroll up, which can be slow for conversations spanning years. Be patient — scroll up to your starting point, wait for messages to load, then start capturing downward.

Group chats. Group iMessage chats work the same way. The conversation layout includes all participants' messages with their names, so the PDF is a complete record of who said what.

Tapback reactions. Heart, thumbs up, and other Tapback reactions appear on messages and are captured in the screenshot.

Attachments. Photos and videos shared in iMessage appear inline. Photos are captured at their displayed size. Videos show as thumbnails.

Privacy and Redaction

Chat conversations almost always contain private information — real names, phone numbers, addresses, financial details, personal discussions. Before storing or sharing archived PDFs, you should consider redacting sensitive content.

Redacting with Preview.app

Shotomatic captures content but doesn't include annotation or redaction tools. For redaction, use macOS's built-in Preview.app:

1. Open the exported PDF in Preview.app
2. Go to Tools → Redact (or click the redaction tool in the markup toolbar)
3. Select the text or area you want to redact
4. Preview draws a black box over the selected content
5. Important: Click File → Save — the redaction isn't permanent until you save
6. Once saved, the redacted content is permanently removed from the PDF — it's not just hidden, it's gone

What to Consider Redacting

• Phone numbers and addresses — especially in group chats
• Financial information — account numbers, transaction details
• Third-party personal information — other people's details shared in conversation
• Passwords or credentials — sometimes shared in DMs
• Private personal discussions — if you're archiving a work channel, personal side conversations may not belong in your archive

Consent and Ethics

Before archiving conversations, consider the other participants:

• Workplace chats: Check your company's data retention policies. Some organizations have rules about exporting Slack messages.
• Private conversations: The other person may not expect the conversation to be permanently archived. Use good judgment.
• Group chats: Multiple people's messages are captured. Consider whether everyone would be comfortable with their messages being archived.

This isn't a legal guide — use your own judgment about what's appropriate to save and store.

Organizing Your Chat Archive

Naming Convention

Platform_Contact-or-Channel_DateRange.pdf

Examples:

• Slack_engineering-decisions_2026Q1.pdf
• Discord_StudyGroup_General_202603.pdf
• iMessage_JohnDoe_20260101-20260322.pdf
• Slack_project-alpha_Thread-DeploymentPlan.pdf

Folder Structure

Chat Archive/
├── Slack/
│   ├── WorkspaceName/
│   │   ├── Channels/
│   │   └── DMs/
├── Discord/
│   ├── ServerName/
│   │   └── Channels/
├── iMessage/
│   ├── Individual/
│   └── Groups/

Searchability

PDF export includes OCR automatically. This turns your chat archive into a searchable document instead of a folder of images. Looking for that deployment configuration someone shared in Slack three months ago? Search "nginx config" in Finder and find it instantly — even though the original Slack message is past the 90-day limit.

If your archive starts as screenshots, the same principle applies to other capture-heavy workflows: searchable PDFs make saved screenshots easier to find later.

Tips for Better Chat Captures

Start from the right point. Don't capture an entire five-year conversation if you only need the last three months. Scroll to the relevant starting point before beginning capture.

Use a consistent window size. Keep the chat application at a consistent window width across captures. This makes the PDFs uniform and easier to read.

Capture during low-activity periods. If the channel is actively being used while you capture, new messages will appear during the process. For the cleanest capture, choose a quiet time.

Close sidebars and panels. In Slack, close the channel details sidebar. In Discord, close the member list. This gives the chat area maximum width and makes the most of each captured frame.

Check the scroll direction. Slack and Discord show newest messages at the bottom. When you start capturing from an older point, Page Down scrolls you toward newer messages. Make sure you're scrolling in the right direction.

Break long archives into manageable chunks. A year-long Slack channel might produce a 500-page PDF. Consider splitting by month or quarter for easier navigation.

FAQ

Does Slack's free plan really delete messages?

Slack's free plan limits message history to 90 days. After 90 days, older messages become inaccessible. If important decisions, links, or instructions live in those messages, you lose access to them.

Can I export my full Slack or Discord history through the app?

Slack workspace owners can request a full export, but individual users on free plans cannot. Discord has a data request option but it returns your own messages in raw JSON, not readable conversations. Screenshot capture gives you the visual conversation as it appeared.

How do I handle private or sensitive information in chat captures?

After exporting to PDF, open the file in Preview.app and use the redaction tool to black out sensitive information. Shotomatic captures content but doesn't have annotation features — use Preview.app for redaction.

Will the PDFs include images and emoji shared in chat?

Yes. Screenshots capture everything visible on screen — text, emoji, images, GIFs (as still frames), link previews, and reactions. The visual conversation is preserved exactly as it appeared.

Can I search through my saved chat archives?

Yes. PDF export includes OCR automatically, so all text in your chat screenshots becomes searchable through Finder and Spotlight. Search for usernames, keywords, dates, or any text that appeared in the conversation.

What about voice and video call content?

This guide covers text chat only. Voice and video calls aren't captured by screenshots. For call recordings, you'd need separate recording software with appropriate consent from all participants.

Don't Wait for the 90-Day Wall

The best time to archive a conversation is before you need to. Slack's 90-day limit, Discord server deletions, and iMessage sync issues are all things that happen without warning. By the time you realize you need a message, it might already be gone.

Set a quarterly reminder to archive important channels and conversations. A few minutes of capture work gives you permanent access to discussions that would otherwise disappear.

Shotomatic has a free trial with limited captures, and paid plans for unlimited use. Everything runs locally on your Mac.

Download Shotomatic