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, its RevenueBase Smart Search rating, 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 Smart Search, 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 contacts → | ||||
Indirect evidence “Slack is on a mission to make people's working lives simpler, more pleasant and more productive.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 2 | 760 contacts → | ||||
Indirect evidence “Café helps enterprises drive collaboration, engagement, and cohesion through real-world interactions.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 3 | 487 contacts → | ||||
Strong evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 4 | 426 contacts → | ||||
Strong evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 5 | 270 contacts → | ||||
Partial evidence “The Firstup Intelligent Communication Platform equips organizations to improve productivity, retention, labor efficiency, safety compliance, and revenue performance by activating…” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 6 | 103 contacts → | ||||
Partial evidence “Fuze is a global cloud communications and collaboration software platform for the enterprise that was acquired by 8x8.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 7 | 97 contacts → | ||||
Indirect evidence “Finishing your product shouldn’t be harder than building it.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 8 | 83 contacts → | ||||
Strong evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 9 | 79 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 10 | 74 contacts → | ||||
Strong evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 11 | 63 contacts → | ||||
Indirect evidence “Swit is every team's work hub that consolidates collaboration essentials in one place - task, chat, goals, approvals, and integrations.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 12 | 62 contacts → | ||||
Indirect evidence “Business Class Team Texting to help Sales and Service Teams!” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 13 | 49 contacts → | ||||
Indirect evidence “Axero provides easy-to-use intranet software that boosts productivity, unifies your people, and helps your company thrive.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 14 | 48 contacts → | ||||
Indirect evidence “Zenzap is the professional work chat app trusted by businesses worldwide.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 15 | 36 contacts → | ||||
Indirect evidence “Agility is the greatest advantage in the modern marketplace.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 16 | 35 contacts → | ||||
Strong evidence “HubEngage™ is a unified employee communications, engagement, recognition and instant messaging platform.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 17 | 30 contacts → | ||||
Indirect evidence “Cerkl Broadcast is the premier, forward-thinking employee communications suite.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 18 | 26 contacts → | ||||
Indirect evidence “Hey there!” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 19 | 26 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 20 | 25 contacts → | ||||
Partial evidence “At 360 SMS, we transform and simplify communication for Salesforce users with our native messaging solution, enhancing connectivity through automated, streamlined, and omnichannel…” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 21 | 22 contacts → | ||||
Indirect evidence “We believe it should be easy to share the right information with the right people, both inside and outside of your team.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 22 | 21 contacts → | ||||
Strong evidence “Avochato is an AI messaging platform built to help businesses have better conversations with their customers.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 23 | 19 contacts → | ||||
Partial evidence “Voxer is a high-performance messaging app that combines the power of live voice with text, photos and videos.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 24 | 17 contacts → | ||||
Indirect evidence “Communicate with your employees in the simplest way possible.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
| 25 | 16 contacts → | ||||
Partial evidence “Threads is an all-in-one communication platform designed for makers.” Source: RevenueBase Database · checked Sep 4, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: internal messaging platforms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names internal messaging platforms.
- Partial evidence
- Its own public description names part of internal messaging platforms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name internal messaging platforms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
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
Freshness & accuracy
How recently the business emails on this list were verified
Email last verified
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 RevenueBase Smart Search 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 Smart Search, 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.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names internal messaging platforms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- 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 its RevenueBase Smart Search 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
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names internal messaging platforms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
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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Internal messaging platforms by geography
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 Smart Search, 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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