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Plumspace beside the chat you may already use.

Plumspace is for a company of tens of people that wants its chat on a server of its own, in Vietnamese and English, paying for a machine rather than for every seat. Here it is next to the five products teams use most, with what it does not do yet said as plainly as what it does.

Where Plumspace is today, 5 October 2026

First written in September 2026. It is not yet packaged for a second company to install on its own, there is no price list, and the iPhone app is on TestFlight by invitation. Everything below is what the product does now, not what is planned.

Side by side

Facts about the other products come from their own pages, checked on 5 October 2026 and listed under Sources. Where a vendor's pages did not say, the cell says see vendor rather than guess. Prices are in US dollars per user per month, before tax.

Scroll sideways for all six: Plumspace, Slack, Microsoft Teams, Google Chat, Mattermost and Rocket.Chat.
Question	Plumspace	Slack	Microsoft Teams	Google Chat	Mattermost	Rocket.Chat
Where your messages are kept	On your own server. Notices to phones and browsers carry the message text through Apple's, Google's and the browsers' push services.	Slack's cloud. A choice of region for stored data on Business+ and Enterprise+.	Microsoft's cloud, as part of Microsoft 365.	Google's cloud, as part of Google Workspace. Data regions on Enterprise plans.	Your own servers, or a single-tenant cloud run by Mattermost for Enterprise.	Your own servers, or dedicated hosting run by Rocket.Chat on paid plans.
Run it on your own server	Yes. The only way it runs: one program and PostgreSQL, also as a container image. One company per install.	No. Sold as hosted plans.	No. Comes with a Microsoft 365 subscription.	No. Comes with a Google Workspace subscription.	Yes. Self-hosted is its main offering, on premises or in a private cloud.	Yes. On premises or private cloud; air-gapped on paid plans.
Source code	No. Closed, all rights reserved. Opening it later is kept possible, not promised.	No. Proprietary.	No. Proprietary.	No. Proprietary.	Yes. Open core: source under AGPLv3, Team Edition under MIT; paid features under a commercial licence.	Yes. Open core: MIT, except its enterprise folders, which have a licence of their own.
Price for 30 people	No price list yet. Running it costs one small server of your own, the same at 10 people or 40.	Pro $7.25 billed yearly ($8.75 monthly): about $218 a month for 30. Business+ $15 billed yearly.	Teams Essentials $4.00, paid yearly: $120 a month for 30. Microsoft 365 Business Basic with Teams $7.00.	Business Starter $7 with a one-year commitment ($8.40 flexible): $210 a month for 30, before introductory discounts.	Free editions (Entry, Team Edition) on your own server. Paid plans priced by sales.	Starter is free up to 50 users on your own server. Paid plans priced by sales.
History on the free plan	Yes. No limit, and nothing is ever deleted. There is no retention policy to set either.	Free: the last 90 days can be read and searched; data is deleted after a year.	No free business plan. Teams (free) is for individuals.	No free Workspace plan; a 14-day trial.	Entry: the latest 10,000 channel messages can be read; older ones stay in the database.	Starter: searchable history, no limit listed.
Voice and video calls	partly Voice and video between two people, with no outside service in between. No group calls, no screen sharing.	Yes. Huddles with video and screen sharing; one to one on Free.	Yes. Meetings of up to 300 people and 30 hours on business plans.	Yes. Google Meet: 100 participants on Starter, more on higher plans.	Yes. One-to-one calls with screen sharing, and group calls. Entry calls are to stop at 40 minutes in a future release.	partly Through video services it connects to: Pexip, Jitsi, BigBlueButton, Google Meet, Zoom.
Apps	partly Web, Windows, Mac (Apple silicon), Android. iPhone through TestFlight, by invitation. The Windows installer is unsigned, so Windows warns once on the first install.	Yes. Web, Windows, Mac, Linux, iPhone, Android.	Yes. Web, Windows, Mac, iPhone, Android.	Yes. Web (installable from Chrome to the desktop), iPhone, Android.	Yes. Web, Windows, Mac, Linux, iPhone, Android.	Yes. Web, Windows, Mac, Linux, iPhone, Android.
Vietnamese	Yes. Vietnamese and English: a language for the workspace, and each person may pick their own. Search finds Vietnamese typed without its accents.	No. Not among Slack's display languages; messages in Vietnamese work.	Yes. Among the languages Microsoft lists for Teams.	Yes. Among the Chat app's listed languages.	Yes. One of its 20 interface languages.	partly One of 64 interface languages; about 2,800 of its 7,500 English strings had a Vietnamese translation.
Guests from outside the company	No. No guest accounts: everyone is a member of the one company.	Yes. On paid plans.	Yes. Guest access on business plans.	see vendor	Yes. Guest accounts.	see vendor
Who in the company can read private conversations	Only an owner, with a written reason, read only, an hour at a time. Every look goes in a trail all owners and admins read. Admins who are not owners cannot.	Owners and admins can export every message, private channels and direct messages included, on Business+ and Enterprise+.	see vendor	Vault keeps and searches the organisation's data on Business Plus and up.	Compliance export and eDiscovery on Enterprise; none in Entry.	see vendor
Integrations and bots	partly Webhooks in and out, bots, slash commands, buttons and forms from an app's manifest, and an n8n node. No app directory.	Yes. Over 2,600 apps in its directory; 10 on Free.	Yes. Over 250 business apps listed.	Yes. Chat apps such as Asana, Jira and Zapier; its own API and Apps Script.	Yes. Plugins, REST API, webhooks and slash commands.	Yes. Marketplace apps, its Apps Engine and an open API.
Single sign-on	No. Passwords, with two-step sign-in the workspace can require of admins or of everyone.	Yes. Sign in with Google on Pro; SAML on Business+ and up.	Yes. Microsoft Entra ID.	Yes. Google accounts, or SAML and OIDC with another identity provider.	Yes. SAML, OpenID Connect and AD/LDAP in Entry and the paid plans; not in Team Edition.	Yes. LDAP and single sign-on, on Starter too.

Left out on purpose: reading recent messages with no connection, and search that ignores Vietnamese accents. Plumspace does both (offline reading in the browser, the desk app and Android, not yet on an iPhone), but the other vendors' pages did not say either way, so there is nothing fair to put beside it.

Honestly

When to choose something else

Plumspace does a narrow job well. If one of these is what you need, one of the others will serve you better today.

Calls with the whole team

Plumspace calls are between two people, with no screen sharing. For meetings, Teams and Google Meet hold hundreds of people, and Slack huddles and Mattermost both share a screen.

No server to look after

Plumspace only runs on a machine you keep. If nobody in the company should own a server, Slack, Teams and Google Chat are run for you.

Single sign-on, guests and legal hold

Plumspace has no single sign-on, no guest accounts and no legal hold. The others list some or all of these on their business and enterprise plans; the table and each vendor's page say which.

End-to-end encryption or federation

Plumspace's server reads messages so it can search them and put the text in a phone's notice. Rocket.Chat lists end-to-end encryption and Matrix federation, and Mattermost Enterprise connects workspaces across servers.

A long record and large scale

Plumspace began in September 2026. The others have served large organisations for years; if you need that track record, take it.

A ready install, today

A second company cannot yet install Plumspace by itself: there is no packaged install, and push to phones for a second workspace is not built. Mattermost and Rocket.Chat install from their own guides now.

Moving over

Moving from Rocket.Chat or Slack

From Rocket.Chat

People come across: addresses, handles, names, photographs and the rooms each one is in, read from the Rocket.Chat install by a script and checked whole before anything is written.
Nobody gets a password until an admin gives them one, and people who have left arrive locked, so their old messages can keep a name and a face.
Messages and files do not come across yet. Keep the old install readable until they do.
Machines keep working: webhooks and chat.postMessage in Rocket.Chat's shape post here with only the address changed, and so does n8n's Rocket.Chat node.

From Slack

No importer. Slack's history stays in Slack. People are made in the console, or brought in from a file in the same plain format the Rocket.Chat import writes.
Incoming webhooks carry over: a flow that posts Slack's text and attachments arrives here with only its URL changed.
Apps do not: Slack's directory apps have no counterpart. Plumspace apps are installed from a manifest your company points it at.

And Zalo?

Most Vietnamese workplaces already talk on Zalo.

For good reasons: it is free, it is Vietnamese, most people already have it (Zalo Group counts more than 81 million users), and it runs on phones, Windows, Mac and the web, with a desktop app it describes as made for group chat and work. It is a service Zalo Group runs. Plumspace is for the moment a company wants its conversations on a machine of its own, with rooms, threads and accounts that belong to the company; until then, Zalo is a fair choice.

Sources

Each page was read on the date given. Prices and plans change; the vendor's page is the authority. Plumspace's column is from its own documentation and code as of 5 October 2026.

slack.com/pricing: plans, prices, free history, huddles, SSO, data residency, exports. Checked 5 October 2026.
Slack: Manage your language preferences. Checked 5 October 2026.
Slack: Understand guest roles in Slack. Checked 5 October 2026.
Slack: System requirements. Checked 5 October 2026.
Microsoft Teams: Compare business options: prices, meetings, guest access, apps, Entra ID. Checked 5 October 2026.
Microsoft Teams: Download: apps, Teams (free) for individuals. Checked 5 October 2026.
Microsoft: Languages supported in Teams and Teams on the App Store. Checked 5 October 2026.
workspace.google.com/pricing: plans, prices, Meet, Vault, data regions, trial. Checked 5 October 2026.
Google Chat product page: included in Workspace, apps and API. Checked 5 October 2026.
Google: Install the Chat standalone app, Google Chat on the App Store and on Google Play. Checked 5 October 2026.
Google Workspace: Set up SSO. Checked 5 October 2026.
mattermost.com/pricing: plans, features in every offering, seats, cloud. Checked 5 October 2026.
Mattermost: Editions and offerings: Entry limits, Team Edition, licences, languages, SSO. Checked 5 October 2026.
rocket.chat/pricing: paid plans, hosting, federation. Checked 5 October 2026.
Rocket.Chat: Get started: the Starter plan. Checked 5 October 2026.
Rocket.Chat: Our plans and Install desktop and mobile apps. Checked 5 October 2026.
Rocket.Chat licence and its translations (Vietnamese strings counted against English). Checked 5 October 2026.
zalo.me, zalo.me/pc and Zalo on the App Store: users, apps, price. Checked 5 October 2026.