Company lists · Data refreshed September 2026

Top 25 Internal communication platforms based in the United States

RevenueBase identified 224 internal communication platforms headquartered in the United States as of September 2026 and tracks 6,840 professional contacts across them, including 996 with verified work emails and 1,784 with mobile numbers. San Francisco is the largest hub.

This list covers internal communication platforms headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, how directly it supports the match, and when it was last checked. Data refreshed September 4, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row Match evidence on every row Refreshed Sep 4, 2026 86% judged on-target in blind review
224Companies
6,840Contacts tracked
996Verified emails
1,784Mobile numbers
Unlock all 224 companies Free signup · no credit card · 500 free credits

The 25 largest internal communication platforms based in the United States

Ranked by team size
Top 25 of 224 internal communication platforms based in the United States, ranked by team size, largest first. Data refreshed Sep 4, 2026. Evidence rates how directly each company's own description names internal communication platforms: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
SLACKIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 20261,001-5,0002,591

“Slack is on a mission to make people's working lives simpler, more pleasant and more productive.”

Source: company website · checked Sep 4, 2026
2
Café YC S21Indirect evidence
NY, United StatesHQ checked Sep 4, 2026n/a760

“Café helps enterprises drive collaboration, engagement, and cohesion through real-world interactions.”

Source: company website · checked Sep 4, 2026
3
HumandStrong evidence
San Francisco, CA, United StatesHQ checked Sep 4, 2026501-1,000487

“At Humand, we empower companies to digitize their internal communication, culture, and HR processes in one unified platform, recognizing that the future of mid market and…”

Source: company website · checked Sep 4, 2026
4
WorkshopStrong evidence
Omaha, NE, United StatesHQ checked Sep 4, 202651-200426

“Workshop is a modern, purpose-built internal communications platform that helps teams create, send, manage, and measure employee communications in one place, starting with email…”

Source: company website · checked Sep 4, 2026
5
Vitel GlobalPartial evidence
South Plainfield, NJ, United StatesHQ checked Sep 4, 202651-200208

Communication is the backbone of every business.”

Source: company website · checked Sep 4, 2026
6
Jive SoftwarePartial evidence
Austin, TX, United StatesHQ checked Sep 4, 2026501-1,000165

“Jive is the leading provider of modern communication and collaboration solutions for business.”

Source: company website · checked Sep 4, 2026
7
BLINKPartial evidence
Boston, MA, United StatesHQ checked Sep 4, 202651-200152

“Blink is the mobile-first employee experience platform that connects your people, systems, and culture in one super-app.”

Source: company website · checked Sep 4, 2026
8
Fuze An 8x8 CompanyStrong evidence
Boston, MA, United StatesHQ checked Sep 4, 2026501-1,000103

“Fuze is a global cloud communications and collaboration software platform for the enterprise that was acquired by 8x8.”

Source: company website · checked Sep 4, 2026
9
Axios HQStrong evidence
Arlington, VA, United StatesHQ checked Sep 4, 202651-20083

“Axios HQ is the first internal communications management platform to equip organizations with the tools, data, and best practices to be world-class communicators.”

Source: company website · checked Sep 4, 2026
10
AmplispotStrong evidence
New York City, NY, United StatesHQ checked Sep 4, 202651-20079

“Amplispot is the mobile-first company communications platform, used by organizations to increase productivity and empower advocacy by informing and engaging employees with timely…”

Source: company website · checked Sep 4, 2026
11
MIOPartial evidence
Austin, TX, United StatesHQ checked Sep 4, 202611-5074

“Mio is a secure middleware that unlocks cross-platform messaging, file sharing, and meeting initiation for enterprise organizations that use Google Workspace and Microsoft 365…”

Source: company website · checked Sep 4, 2026
12
SWITIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 202651-20063

“Swit is every team's work hub that consolidates collaboration essentials in one place - task, chat, goals, approvals, and integrations.”

Source: company website · checked Sep 4, 2026
13
GatherIndirect evidence
United StatesHQ checked Sep 4, 202611-5058

“Gather is a virtual office where remote teams can meet, chat, and interact like they’re in person.”

Source: company website · checked Sep 4, 2026
14
Multimedia PlusStrong evidence
New York, NY, United StatesHQ checked Sep 4, 202611-5055

“The INCITE platform is a mobile-first communications, training and task management platform designed for today’s modern workforce.”

Source: company website · checked Sep 4, 2026
15
Axero SolutionsIndirect evidence
New York, NY, United StatesHQ checked Sep 4, 202651-20049

“Axero provides easy-to-use intranet software that boosts productivity, unifies your people, and helps your company thrive.”

Source: company website · checked Sep 4, 2026
16
PumbleIndirect evidence
Palo Alto, CA, United StatesHQ checked Sep 4, 202651-20049

“Pumble is a free team alternative to Slack and Microsoft Teams.”

Source: company website · checked Sep 4, 2026
17
Politemail SoftwareStrong evidence
Greenland, NH, United StatesHQ checked Sep 4, 202611-5043

“PoliteMail is an internal communications measurement platform for Microsoft Outlook and Office365.”

Source: company website · checked Sep 4, 2026
18
HaystackIndirect evidence
Los Angeles, WA, United StatesHQ checked Sep 4, 202651-20038

“Haystack reinvented the intranet for the future of work, with a focus on seamless integrations, powerful search capabilities, and consumer-grade design.”

Source: company website · checked Sep 4, 2026
19
SocialchorusIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 202651-20036

“Agility is the greatest advantage in the modern marketplace.”

Source: company website · checked Sep 4, 2026
20
HubengageStrong evidence
Cambridge, MA, United StatesHQ checked Sep 4, 202611-5035

“HubEngage™ is a unified employee communications, engagement, recognition and instant messaging platform.”

Source: company website · checked Sep 4, 2026
21
GradualIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 202611-5031

“Most engagement doesn’t happen inside your product.”

Source: company website · checked Sep 4, 2026
22
ZIGHTPartial evidence
San Francisco, CA, United StatesHQ checked Sep 4, 202611-5031

“Visual work communication tool that helps teams share information faster through instantly shareable videos, gifs, and screenshots with 4 million + users.”

Source: company website · checked Sep 4, 2026
23
CERKLPartial evidence
Blue Ash, OH, United StatesHQ checked Sep 4, 202651-20030

“Cerkl Broadcast is the premier, forward-thinking employee communications suite.”

Source: company website · checked Sep 4, 2026
24
comunica.inIndirect evidence
New York, NY, United StatesHQ checked Sep 4, 202611-5028

“Half your workforce has questions but doesn't know where to ask.”

Source: company website · checked Sep 4, 2026
25
BubblesIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 20261-1024

“Teamwork.”

Source: company website · checked Sep 4, 2026

Showing 25 of 224 internal communication platforms based in the United States

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Internal communication platforms based in the United States at a glance

As of Sep 4, 2026
11-50Median size (employees)
San FranciscoLargest hub · 35 HQs
1,784Contacts with mobile numbers
Sep 4, 2026Data refreshed

Companies by employee count

1-10
90
11-50
93
51-200
23
201-500
7
501-1,000
4
1,001-5,000
3
10001+
3

Verified emails by last verification

0–30
0
31–60
59
61–90
539
90–180
381
180+
17

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among internal communication platforms, so some rows will be adjacent to the category rather than pure plays. The description and evidence rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “internal communication platforms”. Matching reads each company's description, not its industry code or its name.
What we exclude
Companies whose own description does not clearly place them among internal communication platforms, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and an evidence rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 996 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 4, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Internal communication platforms by metro

  • Internal communication platforms in San Francisco35

Frequently asked

How many internal communication platforms are there based in the United States?

RevenueBase identified 224 internal communication platforms headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

SLACK, headquartered in San Francisco, tops this list with the largest team on record.

Which city has the most internal communication platforms?

San Francisco leads with 35 headquartered companies, followed by New York (19) and Atlanta (7).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 996 verified decision-maker contacts tracked across these 224 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 4, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase SmartSearch, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.