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Company lists · Data refreshed September 2026

Top 25 Sales engagement platform developers based in the United States

Compiled by the RevenueBase Data Team Data refreshed Sep 6, 2026 1,479 companies tracked

RevenueBase identified 1,479 sales engagement platform developers headquartered in the United States as of September 2026 and tracks 38,671 professional contacts across them, including 12,884 with verified work emails and 10,041 with mobile numbers. San Francisco is the largest hub.

This list covers sales engagement platform developers 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 6, 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 6, 2026 86% judged on-target in blind review
1,479Companies
38,671Contacts tracked
12,884Verified emails
10,041Mobile numbers
Explore all 1,479 companies → Free signup · no credit card · 500 free credits

The 25 largest sales engagement platform developers based in the United States

Ranked by team size
Top 25 of 1,479 sales engagement platform developers based in the United States, ranked by team size, largest first. Data refreshed Sep 6, 2026. Evidence rates how directly each company's own description names sales engagement platform developers: 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
KlaviyoIndirect evidence
Boston, MA, United StatesHQ checked Sep 6, 20261,001-5,0002,789

“Klaviyo (NYSE: KVYO) is the autonomous B2C CRM.”

Source: company website · checked Sep 6, 2026
2
MarketstarPartial evidence
Ogden, UT, United StatesHQ checked Sep 6, 20261,001-5,0002,446

“MarketStar is a global B2B sales outsourcing leader with 38+ years of experience driving predictable revenue growth.”

Source: company website · checked Sep 6, 2026
3
6senseIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 6, 20261,001-5,0001,443

“6sense is on a mission to revolutionize the way B2B organizations create revenue by predicting customers most likely to buy and recommending the best course of action to engage…”

Source: company website · checked Sep 6, 2026
4
OutreachPartial evidence
Seattle, WA, United StatesHQ checked Sep 6, 2026501-1,0001,281

“Outreach, founded in 2014, is the only complete agentic AI platform for revenue teams.”

Source: company website · checked Sep 6, 2026
5
SeismicIndirect evidence
San Diego, CA, United StatesHQ checked Sep 6, 20261,001-5,0001,256

“Seismic is the global leader in enablement, helping organizations engage customers, enable teams, and ignite revenue growth.”

Source: company website · checked Sep 6, 2026
6
CienceIndirect evidence
Miami, FL, United StatesHQ checked Sep 6, 2026201-5001,068

“CIENCE Technologies, Inc, founded in 2015 and headquartered in Denver, CO, is a pioneering global company in lead generation software and services, committed to transforming the…”

Source: company website · checked Sep 6, 2026
7
PipedrivePartial evidence
New York, NY, United StatesHQ checked Sep 6, 2026501-1,000970

“Founded in 2010, Pipedrive is an easy and effective sales CRM that drives small business growth.”

Source: company website · checked Sep 6, 2026
8
apollo.ioStrong evidence
San Francisco, CA, United StatesHQ checked Sep 6, 2026501-1,000863

“Apollo.io is the AI-powered end-to-end go-to-market platform that empowers sales, marketing, and revenue teams to find prospects, engage customers, and close deals with…”

Source: company website · checked Sep 6, 2026
9
MemoryblueIndirect evidence
Tysons, VA, United StatesHQ checked Sep 6, 2026501-1,000825

“memoryBlue is the go-to partner for revenue leaders in B2B Tech looking to grow their pipeline engine.”

Source: company website · checked Sep 6, 2026
10
On24Indirect evidence
San Francisco, CA, United StatesHQ checked Sep 6, 2026501-1,000622

“ON24, a Cvent company, is on a mission to help businesses bring their go-to-market strategy into the AI era and drive cost-effective revenue growth.”

Source: company website · checked Sep 6, 2026
11
SugaraiIndirect evidence
Denver, CO, United StatesHQ checked Sep 6, 2026501-1,000576

“SugarAI: the CRM that actually helps sellers sell.”

Source: company website · checked Sep 6, 2026
12
Adobe MarketoStrong evidence
San Jose, CA, United StatesHQ checked Sep 6, 20261,001-5,000572

“Adobe Marketo Engage offers the leading Engagement Platform that empowers marketers to build brand value, grow revenue, and prove impact.”

Source: company website · checked Sep 6, 2026
13
The Pipeline GroupIndirect evidence
San Jose, CA, United StatesHQ checked Sep 6, 2026201-500523

“The Pipeline Group helps B2B tech companies scale pipeline fast through our SDR-as-a-Service model.”

Source: company website · checked Sep 6, 2026
14
Infoanalytica, INCPartial evidence
San Jose, CA, United StatesHQ checked Sep 6, 2026201-500482

“InfoAnalytica is a B2B sales acceleration partner for mid-market and enterprise companies.”

Source: company website · checked Sep 6, 2026
15
SmarteIndirect evidence
Sunnyvale, CA, United StatesHQ checked Sep 6, 202651-200480

“At SMARTe, we understand the challenges faced by revenue-generating teams.”

Source: company website · checked Sep 6, 2026
16
SaleshiveIndirect evidence
Denver, CO, United StatesHQ checked Sep 6, 202651-200455
Source: company website · checked Sep 6, 2026
17
InvocaPartial evidence
West Hollywood, CA, United StatesHQ checked Sep 6, 2026201-500368

“Invoca is the revenue execution and platform leader that helps marketing, commerce, and contact center teams turn every conversation into revenue.”

Source: company website · checked Sep 6, 2026
18
CallrailStrong evidence
Atlanta, GA, United StatesHQ checked Sep 6, 2026201-500332

“CallRail is the lead engagement platform that makes it easy for businesses to attract more leads, convert more customers, and optimize their marketing.”

Source: company website · checked Sep 6, 2026
19
NOOKSIndirect evidence
San Francisco, CA, United StatesHQ checked Sep 6, 202651-200318

“Nooks is the Agent Workspace for intelligent outbound.”

Source: company website · checked Sep 6, 2026
20
Aviso AIIndirect evidence
Redwood City, CA, United StatesHQ checked Sep 6, 2026201-500297

“Aviso delivers Agentic AI that turns insights into autonomous actions, giving GTM teams precision, speed, and control to drive predictable growth at scale.”

Source: company website · checked Sep 6, 2026
21
Vinsolutions By COX AutomotiveIndirect evidence
Mission, KS, United StatesHQ checked Sep 6, 2026501-1,000292

“VinSolutions is automotive CRM software designed to help dealerships turn shopper behavior into action-and results.”

Source: company website · checked Sep 6, 2026
22
Warrior PlusStrong evidence
Henderson, NV, United StatesHQ checked Sep 6, 2026n/a260

“Best-in-class sales & marketing automation platform and marketplace for digital business owners and online marketers”

Source: company website · checked Sep 6, 2026
23
BigtincanIndirect evidence
Waltham, MA, United StatesHQ checked Sep 6, 2026201-500249

“Bigtincan is now officially part of Showpad.”

Source: company website · checked Sep 6, 2026
24
ConvosoStrong evidence
Los Angeles, CA, United StatesHQ checked Sep 6, 2026201-500241

“Convoso is an AI-powered contact center platform built for revenue teams and customer engagement organizations expanding into outbound growth.”

Source: company website · checked Sep 6, 2026
25
TactonPartial evidence
Chicago, IL, United StatesHQ checked Sep 6, 2026201-500232

“Tacton is a leading SaaS company redefining buyer engagement for manufacturers of complex products.”

Source: company website · checked Sep 6, 2026

Showing 25 of 1,479 sales engagement platform developers based in the United States

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Sales engagement platform developers based in the United States at a glance

As of Sep 6, 2026
1-10Median size (employees)
San FranciscoLargest hub · 146 HQs
10,041Contacts with mobile numbers
Sep 6, 2026Data refreshed

Companies by employee count

1-10
800
11-50
493
51-200
136
201-500
28
501-1,000
11
1,001-5,000
10
10001+
1

Verified emails by last verification

0–30
11,902
31–60
823
61–90
6
90–180
4
180+
149

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 sales engagement platform developers, 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 “sales engagement platform developers”. 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 sales engagement platform developers, 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, 12,884 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 6, 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.

Sales engagement platform developers by metro

Frequently asked

How many sales engagement platform developers are there based in the United States?

RevenueBase identified 1,479 sales engagement platform developers 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?

Klaviyo, headquartered in Boston, tops this list with the largest team on record.

Which city has the most sales engagement platform developers?

San Francisco leads with 146 headquartered companies, followed by New York (92) and Los Angeles (46).

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 12,884 verified decision-maker contacts tracked across these 1,479 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 6, 2026.

Ready to reach these companies? Verified emails and direct dials for all 1,479 sales engagement platform developers based in the United States. Start with a free account, no credit card.

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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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