Company lists · Data refreshed September 2026
Top 25 Internal messaging platforms based in the United States
RevenueBase identified 187 internal messaging platforms headquartered in the United States as of September 2026 and tracks 6,583 professional contacts across them, including 1,062 with verified work emails and 1,792 with mobile numbers. San Francisco is the largest hub.
This list covers internal messaging 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.
The 25 largest internal messaging platforms based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 2,591 | ||||
“Slack is on a mission to make people's working lives simpler, more pleasant and more productive.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 2 | 760 | ||||
“Café helps enterprises drive collaboration, engagement, and cohesion through real-world interactions.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 3 | 487 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 4 | WorkshopStrong evidence | 426 | |||
“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, 2026Thanks. The Data Team will review it. | |||||
| 5 | 270 | ||||
“The Firstup Intelligent Communication Platform equips organizations to improve productivity, retention, labor efficiency, safety compliance, and revenue performance by activating…” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 6 | 103 | ||||
“Fuze is a global cloud communications and collaboration software platform for the enterprise that was acquired by 8x8.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 7 | 97 | ||||
“Finishing your product shouldn’t be harder than building it.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 8 | 83 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 9 | 79 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 10 | MIOStrong evidence | 74 | |||
“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, 2026Thanks. The Data Team will review it. | |||||
| 11 | 63 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 12 | 62 | ||||
“Business Class Team Texting to help Sales and Service Teams!” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 13 | 49 | ||||
“Axero provides easy-to-use intranet software that boosts productivity, unifies your people, and helps your company thrive.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 14 | ZenzapIndirect evidence | 48 | |||
“Zenzap is the professional work chat app trusted by businesses worldwide.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 15 | SocialchorusIndirect evidence | 36 | |||
“Agility is the greatest advantage in the modern marketplace.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 16 | 35 | ||||
“HubEngage™ is a unified employee communications, engagement, recognition and instant messaging platform.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 17 | 30 | ||||
“Cerkl Broadcast is the premier, forward-thinking employee communications suite.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 18 | 26 | ||||
“Hey there!” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 19 | MessagespringPartial evidence | 26 | |||
“MessageSpring simplifies your communication efforts by reaching audiences who are most important to you through a single platform, with the right message, at the right time, in…” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 20 | 25 | ||||
“At 360 SMS, we transform and simplify communication for Salesforce users with our native messaging solution, enhancing connectivity through automated, streamlined, and omnichannel…” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 21 | 22 | ||||
“We believe it should be easy to share the right information with the right people, both inside and outside of your team.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 22 | 21 | ||||
“Avochato is an AI messaging platform built to help businesses have better conversations with their customers.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 23 | VOXERPartial evidence | 19 | |||
“Voxer is a high-performance messaging app that combines the power of live voice with text, photos and videos.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 24 | TRUHUIndirect evidence | 17 | |||
“Communicate with your employees in the simplest way possible.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 25 | 16 | ||||
“Threads is an all-in-one communication platform designed for makers.” Source: company website · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
Showing 25 of 187 internal messaging platforms based in the United States
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Internal messaging platforms based in the United States at a glance
As of Sep 4, 2026Companies by employee count
Verified emails by last verification
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 messaging 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 messaging 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 messaging 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, 1,062 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 messaging platforms by metro
- Internal messaging platforms in San Francisco31
Frequently asked
How many internal messaging platforms are there based in the United States?
RevenueBase identified 187 internal messaging 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 messaging platforms?
San Francisco leads with 31 headquartered companies, followed by New York (9) and Chicago (8).
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 1,062 verified decision-maker contacts tracked across these 187 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.
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