Interact
Interact opens its intranet to outside AI assistants and uses Claude to attack its own platform.
Comparison · Collab
Mattermost vs Slack
A side-by-side editorial comparison of Mattermost and Slack — release velocity, themes, recent moves, and the top alternatives to consider.
Mattermost vs Slack: at a glance
What is Mattermost?
Mattermost v12.1 puts bots and burn-after-reading messages under the same access rules.
Mattermost v12 shipped in parts: agents limited to the requesting user's access, Cross Guard for transfers across security domains, and user, device and channel attributes in access policy. A November 9 partnership pairs v12 with Arqit's quantum-safe device trust. v12.1 on November 13 extends attribute-based access control to bot accounts and to Burn-on-Read permissions, and Desktop v6.4 fixes Boards on subpath deployments.
What is Slack?
Slack now hosts any A2A agent without Slack-specific code.
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
Mattermost vs Slack: editorial side-by-side
Mattermost
6.3COLLAB
Mattermost v12.1 puts bots and burn-after-reading messages under the same access rules.
◆ Current state
Mattermost v12 shipped in parts: agents limited to the requesting user's access, Cross Guard for transfers across security domains, and user, device and channel attributes in access policy. A November 9 partnership pairs v12 with Arqit's quantum-safe device trust. v12.1 on November 13 extends attribute-based access control to bot accounts and to Burn-on-Read permissions, and Desktop v6.4 fixes Boards on subpath deployments.
◆ Where it's heading
Each release closes another gap in one policy model for who and what can see a message: people, devices, channels, and now automation accounts and ephemeral messages. The audience stays defence and regulated buyers, and point releases are filling in v12 rather than starting new lines.
◆ Prediction
Further v12.x releases likely apply the same attribute rules to more objects, such as files, plugins or AI agent actions, following the pattern of v12.1.
Slack
6.3COMMSCOLLAB
Slack now hosts any A2A agent without Slack-specific code.
◆ Current state
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
◆ Where it's heading
Slack is lowering the cost of putting outside agents in front of its users: first skills as code, then MCP pointers for coding agents, now a standard protocol in place of the Slack app model for agents. The platform is positioning itself as the place where agents built anywhere meet the people who use them.
◆ Prediction
Expect more A2A follow-ups, such as agents appearing in Slackbot or skills surfaces and richer Agent Card features, given how fast the agent releases have stacked up since October.
Mattermost alternatives
Other Collab products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Mattermost.
Nextcloud
Nextcloud's November patches lean on preview speed and sharing fixes across three branches.
Asana
Asana lets Division admins run their own custom roles, on top Enterprise plans only.
Double
Double turns a recorded Chrome session into an agent that repeats the task.
SiYuan
SiYuan 3.8.11 alphas add freeform mind maps and plugin snapshots right after 3.8.10.
Hive
Hive turns reporting into a planning tool: shared inputs, grouped values, per-person drill-downs.
Slack alternatives
Other Collab products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Slack.
Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Twilio
Twilio's voice AI stops cutting callers off mid-sentence, using its own turn-taking model.
Salesmsg
Salesmsg adds call-back requests and a one-click Emergency Stop for all outbound texts.
Element
Element 1.12.35 follows the call picture-in-picture release with one desktop storage fix.
Krisp
Krisp moves call transcripts and live captions to cloud transcription in KrispCX 2.84.4.
Misskey
Misskey 2026.11 ships: a leaner start script, and Node.js 22 no longer boots.
Recent activity from Mattermost and Slack
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 23h agoMattermostMattermost v12.1: Control That Goes Beyond On and Off
- 4d agoSlackBring your A2A agents to Slack ⚡
- 4d agoMattermostYour MFA Isn't Phishing-Resistant. Here's What Is, and What the Deployment Decision Actually Involves
- 4d agoMattermostMattermost v12 pairs with Arqit for quantum-safe edge deployments
- 8d agoSlackWork Objects embeds require the slack-mcps.com frame ancestor
- 9d agoMattermostMattermost v12 adds device and channel attributes to access policy
- 10d agoSlackSlack CLI 4.13 tells coding agents about Slack MCP and Skills
- 10d agoSlackSlack Skills Plugin installs in Claude Code from its own marketplace
- 12d agoSlackUpdated low-usage submission criteria for Slack Marketplace apps
- 15d agoSlackSlack CLI 4.12.0, the fourth CLI release in October
- 18d agoMattermostMattermost v12 Cross Guard: managed cross-domain transfers
- 21d agoMattermostMattermost v12: Agents Are Doing the Work. Now Control What They Can See. ⚡
Frequently asked questions
What is the difference between Mattermost and Slack?
They serve adjacent needs but don't currently overlap on shipped themes. Mattermost and Slack are shipping at a similar cadence (velocity 6.3 vs 6.3, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Mattermost better than Slack?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Mattermost and Slack are shipping at a similar cadence (velocity 6.3 vs 6.3, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other Collab products to evaluate alongside.
What are the best alternatives to Mattermost?
Top Mattermost alternatives in Collab are ranked by recent ship velocity. Browse the "Mattermost alternatives" section above for the current picks, or visit /alternatives/mattermost for the full list with editorial commentary on each.
What are the best alternatives to Slack?
Top Slack alternatives in Collab are ranked by recent ship velocity. Browse the "Slack alternatives" section above for the current picks, or visit /alternatives/slack for the full list with editorial commentary on each.