Threema
Threema ships a rare app change: spam reports for any chat on Android and iOS
Comparison · Comms
Fellow vs Slack
A side-by-side editorial comparison of Fellow and Slack — release velocity, themes, recent moves, and the top alternatives to consider.
Fellow vs Slack: at a glance
What is Fellow?
Fellow's public changelog has been silent since 2021 — no recent direction is observable here.
The visible signal stops in spring 2021. The last few releases were calendar-extension touch-ups: action items appearing directly in the Google Calendar extension, public view-only meeting links for external attendees, and multi-calendar sync within a single Google or Office account. Nothing in this dataset reflects the past several years of Fellow's actual work.
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.
Fellow vs Slack: editorial side-by-side
Fellow
0.0COMMS
Fellow's public changelog has been silent since 2021 — no recent direction is observable here.
◆ Current state
The visible signal stops in spring 2021. The last few releases were calendar-extension touch-ups: action items appearing directly in the Google Calendar extension, public view-only meeting links for external attendees, and multi-calendar sync within a single Google or Office account. Nothing in this dataset reflects the past several years of Fellow's actual work.
◆ Where it's heading
From the entries alone, no current trajectory can be inferred — the data is years stale. Whether Fellow has shifted to AI-meeting-notes or remained focused on the original meeting-management surface is not visible here and would be guesswork to assert.
◆ Prediction
Predictions can't be grounded in this data. The most useful next step is to refresh Fellow's changelog source so that present-day moves are captured.
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 Fellow 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 Fellow or Slack.
Matrix
Matrix 2.0 is weeks from release as the Foundation details its money problem
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.
See all Fellow alternatives → · See all Slack alternatives →
Recent activity from Fellow and Slack
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 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
- 5y agoFellowAction items in Google Calendar extension 📆
- 5y agoFellowPublic links 🔗
- 5y agoFellowSync multiple calendars 📅
Frequently asked questions
What is the difference between Fellow and Slack?
They serve adjacent needs but don't currently overlap on shipped themes. Slack is currently shipping more aggressively (velocity 6.3 vs 0.0), 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 Fellow 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 0.0), 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 Fellow?
Top Fellow alternatives in Comms are ranked by recent ship velocity. Browse the "Fellow alternatives" section above for the current picks, or visit /alternatives/fellow 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.