Company lists · Data refreshed September 2026

Top 24 Internal communication software companies based in the United States

RevenueBase identified 115 internal communication software companies headquartered in the United States as of September 2026 and tracks 5,351 professional contacts across them, including 728 with verified work emails and 1,637 with mobile numbers. San Francisco is the largest hub.

This list covers internal communication software companies 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
115Companies
5,351Contacts tracked
728Verified emails
1,637Mobile numbers
Unlock all 115 companies Free signup · no credit card · 500 free credits

The 24 largest internal communication software companies based in the United States

Ranked by team size
Top 24 of 115 internal communication software companies 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 software companies: 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
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
3
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
4
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
5
SMILEIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 4, 2026n/a153

“With TextExpander, created by Smile, you can communicate smarter.”

Source: company website · checked Sep 4, 2026
6
Smash SolutionsIndirect evidence
South Jordan, UT, United StatesHQ checked Sep 4, 202651-200141

“Smash is solution that integrates the latest innovative technological components into accessible, all-inclusive solutions that bridge each aspect of professional and personal…”

Source: company website · checked Sep 4, 2026
7
ROI CommunicationStrong evidence
Scotts Valley, CA, United StatesHQ checked Sep 4, 202651-20089

“ROI Communication is a 100% employee-owned internal communications company focused on helping the world’s leading businesses achieve their very best through inspired employee…”

Source: company website · checked Sep 4, 2026
8
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
9
Axero SolutionsPartial 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
10
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
11
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
12
HubengagePartial 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
13
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
14
GuidesparkPartial evidence
Redwood City, CA, United StatesHQ checked Sep 4, 2026201-50018

“GuideSpark is the leader in change communications guiding over enterprise customers to business success by changing the hearts and minds of employees.”

Source: company website · checked Sep 4, 2026
15
TRUHUIndirect evidence
Pleasanton, CA, United StatesHQ checked Sep 4, 202611-5017

“Communicate with your employees in the simplest way possible.”

Source: company website · checked Sep 4, 2026
16
ZELOPartial evidence
San Francisco, CA, United StatesHQ checked Sep 4, 20261-1014

“Zelo redefines how companies communicate internally.”

Source: company website · checked Sep 4, 2026
17
Connecto APPPartial evidence
DE, United StatesHQ checked Sep 4, 202611-5012

“Connecto App es una aplicación móvil personalizable que te permitirá fortalecer todos los procesos de comunicación interna, logrando que sea más eficiente y ¡Lo mejor!”

Source: company website · checked Sep 4, 2026
18Bellevue, WA, United StatesHQ checked Sep 4, 202651-2009

“Intentional is creating innovative software that will transform the way organizations collaborate to create and share ideas.”

Source: company website · checked Sep 4, 2026
19
Kavi CorporationIndirect evidence
Portland, OR, United StatesHQ checked Sep 4, 202611-509

“Kavi was acquired by Higher Logic in February 2017.”

Source: company website · checked Sep 4, 2026
20
PROZEIndirect evidence
Bellevue, WA, United StatesHQ checked Sep 4, 202611-507

“Proze empowers organizations to turn email into a strategic advantage.”

Source: company website · checked Sep 4, 2026
21
RepticityPartial evidence
New York, United StatesHQ checked Sep 4, 202651-2007

“Repticity is an all-in-one communication and work management platform.”

Source: company website · checked Sep 4, 2026
22
BrosixIndirect evidence
Wilmington, DE, United StatesHQ checked Sep 4, 202611-506

“Offers an easy-to-use, affordable enterprise instant messenger featuring advanced security, privacy, and customization.”

Source: company website · checked Sep 4, 2026
23
KonversePartial evidence
Miami, IL, United StatesHQ checked Sep 4, 202611-506

“Konverse is an all-in-one communication platform designed for nondesk workers.”

Source: company website · checked Sep 4, 2026
24
AssemblePartial evidence
Austin, TX, United StatesHQ checked Sep 4, 20261-106

“Assemble builds collaboration software for the future of work.”

Source: company website · checked Sep 4, 2026

Showing 24 of 115 internal communication software companies based in the United States

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Internal communication software companies based in the United States at a glance

As of Sep 4, 2026
11-50Median size (employees)
San FranciscoLargest hub · 18 HQs
1,637Contacts with mobile numbers
Sep 4, 2026Data refreshed

Companies by employee count

1-10
44
11-50
46
51-200
15
201-500
5
501-1,000
2
1,001-5,000
1
5,001-10,000
1
10001+
1

Verified emails by last verification

0–30
0
31–60
44
61–90
410
90–180
266
180+
8

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 software companies, 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 software companies”. 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 software companies, 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, 728 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.

Frequently asked

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

RevenueBase identified 115 internal communication software companies 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 software companies?

San Francisco leads with 18 headquartered companies, followed by New York (8) and Atlanta (5).

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 728 verified decision-maker contacts tracked across these 115 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.