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Comparison · Comms
Slack vs Threema
A side-by-side editorial comparison of Slack and Threema — release velocity, themes, recent moves, and the top alternatives to consider.
Slack vs Threema: at a glance
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.
What is Threema?
Threema ships a rare app change: spam reports for any chat on Android and iOS
On 13 November Threema improved spam reporting so users can flag single and group chats as spam on all mobile platforms, a change it credits to feedback from its in-app survey feed. It is the first app-level change in this window; the rest of the feed since July is security commentary, an August DDoS incident post and two Threema Work admin features.
Slack vs Threema: editorial side-by-side
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.
Threema
5.0COMMS
Threema ships a rare app change: spam reports for any chat on Android and iOS
◆ Current state
On 13 November Threema improved spam reporting so users can flag single and group chats as spam on all mobile platforms, a change it credits to feedback from its in-app survey feed. It is the first app-level change in this window; the rest of the feed since July is security commentary, an August DDoS incident post and two Threema Work admin features.
◆ Where it's heading
Product news is starting to surface in the consumer app as well as in Threema Work administration, but at a slow pace and in small steps. The editorial line stays on security and resilience, with recent posts pitching Threema as the fallback channel during cyberattacks.
◆ Prediction
Expect further small, feedback-driven app changes alongside security commentary; the entries do not show when the larger items teased in July's roadmap post will ship.
Alternatives to Slack and Threema
Other Comms products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Slack or Threema.
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.
See all Slack alternatives → · See all Threema alternatives →
Recent activity from Slack and Threema
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoThreemaImproved Spam Reporting for Android and iOS
- 4d agoSlackBring your A2A agents to Slack ⚡
- 8d agoSlackWork Objects embeds require the slack-mcps.com frame ancestor
- 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
- 12d agoThreemaWhen Systems Go Silent: Staying Connected During a Cyberattack
- 15d agoSlackSlack CLI 4.12.0, the fourth CLI release in October
- 26d agoThreemaWhat’s behind the current wave of cyberattacks?
- 3mo agoThreemaDDoS Attacks on Threema
- 3mo agoThreemaMessenger Interoperability: Well-Intended, but Bad for Data Privacy
- 3mo agoThreemaEasier Tag Management in the Management Cockpit
Frequently asked questions
What is the difference between Slack and Threema?
They serve adjacent needs but don't currently overlap on shipped themes. Slack is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Slack better than Threema?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Slack is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Comms products to evaluate alongside.
What are the best alternatives to Slack?
Top Slack alternatives in Comms 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.
What are the best alternatives to Threema?
Top Threema alternatives in Comms are ranked by recent ship velocity. Browse the "Threema alternatives" section above for the current picks, or visit /alternatives/threema for the full list with editorial commentary on each.