Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Comparison · Comms
Tuta vs Slack
A side-by-side editorial comparison of Tuta and Slack — release velocity, themes, recent moves, and the top alternatives to consider.
Tuta vs Slack: at a glance
What is Tuta?
Tuta's One-Click Migration can now pull mail through Google and Microsoft APIs, not just IMAP.
Tuta is an encrypted email, calendar and drive suite that ships one numbered build across web, desktop, Android and iOS. The 368.261109 build adds the option to open attachments while composing and lets One-Click Migration import from Gmail and Microsoft accounts through their APIs as well as IMAP. The rest of the batch is bug fixes: list selection flashing, spam rules not updating, alias deactivation for shared mailboxes and connection errors during migration.
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.
Tuta vs Slack: editorial side-by-side
Tuta
5.0COMMS
Tuta's One-Click Migration can now pull mail through Google and Microsoft APIs, not just IMAP.
◆ Current state
Tuta is an encrypted email, calendar and drive suite that ships one numbered build across web, desktop, Android and iOS. The 368.261109 build adds the option to open attachments while composing and lets One-Click Migration import from Gmail and Microsoft accounts through their APIs as well as IMAP. The rest of the batch is bug fixes: list selection flashing, spam rules not updating, alias deactivation for shared mailboxes and connection errors during migration.
◆ Where it's heading
The visible product work is aimed at switching: the migration tool keeps gaining source options and its error handling is getting attention, including the Proton Mail Bridge path. Releases fan out to every platform within hours, so most entries are the same fix list repeated per client.
◆ Prediction
Expect more migration fixes and sources in the next builds, plus follow-up patches like the November 10 mailto fix on the web app.
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.
Alternatives to Tuta and Slack
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 Tuta or Slack.
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 Tuta and Slack
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 3d agoTutaTuta web app fixes mailto links
- 3d agoTutaTuta desktop: Gmail and Microsoft API import, attachments in editor
- 4d agoTutaTuta Drive Android fixes list selection flashing
- 4d agoTutaTuta Drive iOS fixes list selection flashing
- 4d agoTutaTuta Calendar iOS fixes list selection flashing
- 4d agoTutaTuta iOS: open attachments in the mail editor
- 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
- 15d agoSlackSlack CLI 4.12.0, the fourth CLI release in October
Frequently asked questions
What is the difference between Tuta and Slack?
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 Tuta better than Slack?
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 Tuta?
Top Tuta alternatives in Comms are ranked by recent ship velocity. Browse the "Tuta alternatives" section above for the current picks, or visit /alternatives/tuta for the full list with editorial commentary on each.
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.