Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Comparison · Comms
Slack vs Signal Desktop
A side-by-side editorial comparison of Slack and Signal Desktop — release velocity, themes, recent moves, and the top alternatives to consider.
Slack vs Signal Desktop: 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 Signal Desktop?
Signal Desktop's 8.36 beta adds favorite sticker packs after a fix-only week.
Signal Desktop ships a beta roughly weekly, and most builds since September carry only generic fix notes. v8.36.0-beta.1 adds favorite sticker packs, so the ones a user relies on stay at hand. It follows the fix-only v8.35.0-beta.1 and v8.34.0-beta.1, which added contact sharing from desktop and better audio device handling.
Slack vs Signal Desktop: 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.
Signal Desktop
5.0COMMS
Signal Desktop's 8.36 beta adds favorite sticker packs after a fix-only week.
◆ Current state
Signal Desktop ships a beta roughly weekly, and most builds since September carry only generic fix notes. v8.36.0-beta.1 adds favorite sticker packs, so the ones a user relies on stay at hand. It follows the fix-only v8.35.0-beta.1 and v8.34.0-beta.1, which added contact sharing from desktop and better audio device handling.
◆ Where it's heading
The desktop app is closing gaps with mobile one feature at a time, separated by maintenance betas. Visible features arrive about every two to three builds.
◆ Prediction
The next feature beta is likely within one or two builds, based on the cadence since October. The entries don't indicate what it will contain.
Alternatives to Slack and Signal Desktop
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 Signal Desktop.
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.
See all Slack alternatives → · See all Signal Desktop alternatives →
Recent activity from Slack and Signal Desktop
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 2d agoSignal Desktop8.36 beta lets users favorite sticker packs
- 4d agoSlackBring your A2A agents to Slack ⚡
- 8d agoSlackWork Objects embeds require the slack-mcps.com frame ancestor
- 8d agoSignal Desktopv8.35.0-beta.1: fix-only beta, no visible changes
- 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
- 16d agoSignal DesktopContact sharing comes to desktop; better audio device handling
- 24d agoSignal Desktopv8.33.0-beta.1: fix-only beta, no visible changes
- 29d agoSignal DesktopUnread filter reaches folders and search; sturdier uploads
- 1mo agoSignal DesktopBug-fix-only beta, no feature changes
Frequently asked questions
What is the difference between Slack and Signal Desktop?
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 Signal Desktop?
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 Signal Desktop?
Top Signal Desktop alternatives in Comms are ranked by recent ship velocity. Browse the "Signal Desktop alternatives" section above for the current picks, or visit /alternatives/signal-desktop for the full list with editorial commentary on each.