Getting Started

Your managed MostlyMatter at server.camp is ready. MostlyMatter is the privacy-first alternative to Slack and Microsoft Teams: team messaging, channels, file sharing, calls, and integrations — all on infrastructure in Germany. This guide is for freelancers, SMBs, and nonprofits that want structured internal communication, independent of US cloud services.

MostlyMatter is based on Mattermost

MostlyMatter is a fork of Mattermost, maintained by Framasoft — a French non-profit organization — that removes the user cap of Mattermost’s free Team Edition. At server.camp it runs as a fully managed service. Its interface and feature set match Mattermost. For any detailed questions, the official Mattermost documentation applies as well: docs.mattermost.com. Wherever this guide refers to the Mattermost interface, the same applies to MostlyMatter.

Many organizations communicate through a mix of email, WhatsApp, and phone calls. The problems: business conversations end up on personal phones, important information disappears in email threads, and new team members have no context for past decisions.

MostlyMatter creates one central communication platform — GDPR-compliant on servers in Germany, not at Slack in the US or Microsoft in some data center.

Common use cases:

• Team communication in structured channels instead of endless email threads
• Project communication — one channel per project, everyone stays informed
• Quick coordination — direct messages and group chats for short questions
• Voice calls with screen sharing — directly in MostlyMatter, no external tool
• Technical notifications — webhooks from GitLab and other systems posted directly to channels
• Boards (Kanban) — task and project management built into MostlyMatter
• Association communication — working groups, board, and members in separate channels

After you order, server.camp sends you an email with the link to your MostlyMatter instance and your login credentials. Open the link and sign in.

The first account is automatically the System Administrator with the username admin. The email address on file is your own. You manage the entire instance with this account.

You reach central administration via the menu at the top left → “System Console”. There you configure branding, registration, and other instance-wide settings.

Keep admin credentials safe

The admin account has full access to all teams, channels, and settings. Keep the credentials safe — ideally in a password manager like Vaultwarden — and enable two-factor authentication (see the Security section).

Under System Console → Customization, you can adapt the instance to your organization:

• Site name — the name shown throughout the interface
• Description — a short subtitle
• Custom text for the login page — e.g. a welcome message for your team

This makes MostlyMatter feel like your own platform from day one.

MostlyMatter has a tenant-level structure called teams. A team is a collection of channels, members, and settings. Within a team, you communicate with colleagues or association members. In most cases, a single team is enough.

Within a team, there are several ways to communicate:

• Channel — a topic-based area within a team (e.g. “Support”, “Project Website”). Channels can be public or private. Use the plus icon to create new channels.
• Group chat — a conversation with 3–7 people, without creating a dedicated channel. Ideal for quick coordination in small groups.
• Direct message — a 1:1 conversation between two people.

MostlyMatter works in any browser, but it also connects to the Mattermost desktop and mobile apps. Install the apps on every device you use — so you never miss a message.

Download at mattermost.com/apps:

• Windows — MSI installer or portable
• macOS — DMG or via Homebrew (brew install --cask mattermost)
• Linux — AppImage, .deb, or .rpm

On first launch: enter your server address — this is the URL of your own MostlyMatter instance from server.camp → sign in.

• iOS: App Store
• Android: Google Play

In the app: “Add Server” → enter the URL of your MostlyMatter instance → sign in.

Desktop app over browser

The desktop app has clear advantages over the browser: independent notifications (not tied to browser state), support for multiple servers, and it doesn’t get lost in tab clutter. For daily use, the desktop app is the better choice.

Under the team menu → “Invite People”, you can add new members — either by email or via an invitation link.

Generate a link and send it to your team. Anyone who opens the link can register themselves.

Enter email addresses. Invitees receive an email with a registration link.

In the System Console, you decide whether self-registration is allowed at all and whether it is restricted to specific email domains (e.g. only @your-company.com).

Restrict registration to your domain

If you allow self-registration, it’s best to restrict it in the System Console to your own email domain(s). That way only people from your organization can register — and you don’t have to invite each person individually.

Limit System Admin access

System Admins can see all channels (including private ones) and change any setting. Assign this role only to people responsible for technical administration — typically 1–2 people.

Every team member can see public channels, join them, and read the full message history. Ideal for topics where transparency is valued.

Only invited members see private channels. They don’t appear in the channel list for others. Ideal for confidential topics.

Default to public

Public channels promote transparency and make knowledge accessible. Use private channels only when there’s a real reason for confidentiality. New employees or association members benefit enormously from being able to read past discussions.

Archive completed projects or unused channels instead of deleting them. Archived channels remain searchable but disappear from the active channel list. Find them under “More…” → “Archived” and restore them if needed.

Keep the channel list small

Start with 5–8 channels and expand as needed. Too many channels from the start leaves everyone unsure where things belong. Let it grow organically.

Use @channel and @all sparingly

@channel and @all notify everyone in the channel — including people in meetings or off for the day. Use these only for genuinely important announcements. For less urgent messages, a normal post without an @-mention is enough.

Reply to a message in a thread instead of directly in the channel: click the reply icon on a message. This keeps the channel view clean and groups related discussions together.

In the sidebar, “Threads” shows an overview of all threads you’re part of — so you never miss a reply.

MostlyMatter supports Markdown:

Click the smiley icon on any message to react with an emoji. Quick reactions like 👍, ✅, or 👀 often replace a full reply and keep the channel clean.

Tip: Agree on team conventions, e.g. 👀 = “I’ve seen this”, ✅ = “Done”, 👍 = “Agreed”.

Use reactions for quick polls

For simple polls (e.g. scheduling), post the question and add possible answers as emoji reactions (e.g. 1️⃣, 2️⃣, 3️⃣). Team members react with their choice — preferences visible at a glance.

• Pin: Important messages can be pinned in a channel — ideal for links, decisions, or recurring information. Find pinned messages via the pin icon in the channel header.
• Bookmarks: Save messages as personal bookmarks to find them later.

Upload files directly to channels (drag and drop or via the paperclip icon). MostlyMatter shows images and PDFs as inline previews in the conversation.

MostlyMatter for communication, cloud storage for files

MostlyMatter is great for quick file exchange in the context of a conversation. For permanent, structured storage, use Nextcloud or Seafile. Share a link to the file in cloud storage via MostlyMatter — the file lives in one place and is referenced in the chat.

MostlyMatter includes built-in voice calls with screen sharing — directly in a channel or direct message, no external tool and no additional software needed. (Webcam video is not part of the call feature; what you share is your screen.)

Calls are already set up at server.camp

The built-in call feature is fully set up at server.camp — including the required connection servers (TURN) so calls work reliably even behind firewalls. You don’t need to configure anything: just start a call.

1. Click the phone icon in the channel header or in a direct message
2. Other participants see a notification and can join
3. During the call: screen sharing for presentations or collaborative work

Calls for quick check-ins

The built-in call is ideal for short questions or quick decisions — no switching to another platform. Call, clarify, hang up.

Boards provide a Kanban board. Manage tasks directly in MostlyMatter — no separate project management tool needed.

Boards is in maintenance mode

The Boards plugin (Focalboard) is now only maintained by Mattermost in maintenance mode (security and bug fixes, no new features) and is no longer enabled by default in recent Mattermost versions.

1. Click “Boards” in the left sidebar
2. Choose “Create new board” or select a template (e.g. project planning, sprint, to-do list)
3. Create cards, define columns (e.g. “To Do”, “In Progress”, “Done”)
4. Cards can have assignees, due dates, descriptions, and comments

To keep MostlyMatter from becoming a distraction, configure notifications thoughtfully.

Under Profile Settings → Notifications:

Under Profile Settings → Notifications → Do Not Disturb, define automatic quiet hours — e.g. from 18:00 to 08:00 and on weekends. No push notifications are sent during these times.

Mute individual channels without leaving them: right-click the channel → Notification Preferences → Mute. Ideal for channels you want to read occasionally but don’t need to be notified for every message (e.g. random).

One of MostlyMatter’s biggest advantages is its deep integration capability via webhooks and slash commands.

Under Integrations → Incoming Webhooks, create a URL that external systems can use to post messages to a MostlyMatter channel.

Especially handy: have GitLab report commits, merge requests, and pipelines via webhook to a channel like #development. Your team sees code changes and build status directly in chat, without constantly checking GitLab.

MostlyMatter supports slash commands — commands starting with / entered directly in chat:

See all slash commands

Type just / in a channel and MostlyMatter shows a list of all available slash commands. A quick way to see what’s available.

MostlyMatter has a powerful full-text search across all messages, channels, and files:

• Click the search icon or use Ctrl+F / Cmd+F
• Search by keywords, people, or file names
• Search modifiers for precise results:
  • from:jane.smith — messages from a specific person
  • in:sales — messages in a specific channel or chat
  • before:2026-02-01 / after:2026-01-15 / on:2026-01-20 — messages in a time range or on a specific day
• For files, filter by file type using the file type filter in the search interface (e.g. only PDFs or only images)

Search as your knowledge base

One of the biggest advantages over WhatsApp and phone calls: everything written in MostlyMatter is searchable. Looking for a decision, a link, or an agreement — search finds it. This only works if important decisions are written down in channels and not just discussed verbally.

MostlyMatter does not currently support single sign-on. We’re working on it, though, and will add details here soon.

Every user can set their status to let the team know what they’re doing:

• Online (green dot) — active
• Away (yellow dot) — briefly unavailable
• Do Not Disturb (red dot) — no notifications
• Offline (gray dot) — not signed in

Set a custom status with an emoji and text (e.g. “🏖️ On vacation until Mar 3” or “📞 On a client call”). This reduces unnecessary messages and signals to the team when you’re available.

Tip for freelancers: Use MostlyMatter as a personal knowledge archive. Create a private channel “Notes” just for yourself — collect links, ideas, and snippets you can find again via search.

Onboarding tip: Create an onboarding channel with pinned messages: links to documentation, key contacts, software access, and team conventions. Every new employee joins this channel and finds everything in one place.

Tip for associations: MostlyMatter works great as a WhatsApp replacement for association communication. Unlike WhatsApp, all communication lives on your own server, no personal phone numbers are shared, and new members can read past discussions. The mobile app is just as easy to use as any messenger.

Have GitLab post notifications about commits, merge requests, and pipelines via webhook to a #development channel. Your development team stays up to speed without constantly checking GitLab.

Share links to files in Nextcloud or Seafile directly in MostlyMatter channels. Files live in structured cloud storage and are referenced in chat — no clutter from duplicate uploads.

Store credentials for MostlyMatter and all other services centrally in Vaultwarden. Everyone on the team always has the right credentials at hand.

Every user can enable TOTP-based 2FA under Profile Settings → Security → Multi-Factor Authentication. Recommended for all users, required for admins.

Under Profile Settings → Security → Active Sessions, see all logged-in devices and end individual sessions — useful if a device is lost.

Need help setting up channels, integrations, boards, or app configuration? Reach out at support@server.camp or via server.camp/support. We’re happy to help.

Since MostlyMatter is based on Mattermost, the official Mattermost documentation also helps with detailed questions. Find frequently asked questions about MostlyMatter on our product page.