Comparison

Zulip vs COSAction

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Zulip

This app provides organized team chat for groups of any size, enabling users to read and respond to messages in context. It helps maintain focus by allowing users to catch up on topics of interest at their own pace. The application is open-source and available as a cloud service or self-hosted solution.

Highlights
  • Organized team chat
  • Contextual message reading
  • Topic-based conversations
  • Focus maintenance
  • Open-source software
  • Cloud and self-hosted options
Features
Read full description

Zulip (https://zulip.com/) helps teams of all sizes be more productive together, from a few friends hacking on a new idea, to globally distributed organizations with hundreds of people tackling the world's hardest problems. Unlike other chat apps, Zulip lets you read and respond to every message in context, no matter when it was sent. Maintain your focus and then catch up on your own time, reading the topics you care about, and skimming or skipping the rest. Like everything Zulip, this official Zulip mobile app is 100% open-source software: https://github.com/zulip/zulip-flutter . Thank you to the hundreds of contributors who have made Zulip what it is! Zulip is available as a managed cloud service or a self-hosted solution. Please send questions, comments, and bug reports to support@zulip.com, or tweet @zulip.

About

COSAction

Empower grassroots activists with tools to connect with state legislators and build local support teams. Access news, track legislative actions, and utilize a phone outreach tool to advance constitutional amendments.

Highlights
  • Legislator contact tools
  • Volunteer team building
  • News articles
  • Action reports
  • Notifications
  • Phone outreach tool
Read full description

COSAction provides information and tools for self-governing grassroots activists to engage with their state legislators, and to build a team of educated and engaged volunteers and supporters in their local district. This app is available for anyone who is a supporter of Convention of States Project. Its goal is to have its resolution passed in at least 34 states, to call for a Convention of States to propose amendments to the US Constitution, which fall within one of 3 subject matters, 1) fiscal restraints, 2) term limits, or 3) reduce scope and jurisdiction of the Federal government. The Mission of Convention of States Project is to "Build an engaged army of self-governing grassroots activists". The Aspirational Goals are: - The people organize and restore representative government as defined in our written Constitution. - Restore a culture of self-governance in America. - Inspire a political and spiritual awakening in America. Current features of the app include: - News articles - Action reports for contacts with legislators - Notifications - TelePatriot phone outreach tool - Leadership directory

Screenshots

Zulip3 screens
COSAction4 screens

Verdict

The call

The clearest difference is review sentiment: COSAction at 100% against Zulip's 39%. COSAction also leads on rating (4.9 vs 3.7) and monetization model (free vs free with in-app purchases). On price, ratings volume, update cadence and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

COSAction holds the better App Store score, 4.9 against 3.7. Both are backed by a comparable volume of ratings — 16 and 10 respectively. Written reviews point the same way: 39% of Zulip's written reviews are positive against 100% of COSAction's.

UpkeepUpdate frequency

Zulip ships an update monthly, COSAction fortnightly. The most recent releases landed on October 20, 2026 and October 6, 2026 respectively.

Scorecard4 real differences · 6 level
Zulip versus COSAction: the parameters behind the verdict, then further details
ParameterZulipCOSAction
PriceFreeFree
Rating3.7 (16 ratings)4.9 (10 ratings) — better
Positive reviews39.3% of reviews100.0% of reviews — better
Number of ratings16 — better10
Update frequencyMonthlyFortnightly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPod
Requires iOS15.010.0 — better
Further details — not scored
Size44 MB39 MB
Age rating12+4+
DeveloperKandra Labs, Inc.Citizens for Self-Governance

Customer experience

Zulip

All ratings16 ratings
Positive62.5%
Neutral12.5%
Negative25.0%
Written reviews89 reviews
Positive39.3%
Neutral13.5%
Negative47.2%

COSAction

All ratings10 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Zulip

No in-app purchases

None

COSAction

No in-app purchases

Questions

Is Zulip free?
Zulip is free to download, with no in-app purchases.
Is COSAction free?
COSAction is free to download, with no in-app purchases.
Which has better reviews, Zulip or COSAction?
COSAction is rated higher. Zulip averages 3.7 out of 5 from 16 ratings, while COSAction averages 4.9 from 10 ratings.
Do Zulip or COSAction have ads?
Neither Zulip nor COSAction shows ads.
Which is updated more often, Zulip or COSAction?
Zulip ships an update monthly, and COSAction fortnightly. Most recently, Zulip was updated on October 20, 2026 and COSAction on October 6, 2026.

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