Company lists · Data refreshed September 2026

Top 25 Engagement letter software companies based in the United States

RevenueBase identified 71 engagement letter software companies headquartered in the United States as of September 2026 and tracks 10,533 professional contacts across them, including 6,791 with verified work emails. San Francisco is the largest hub.

This list covers engagement letter 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 28, 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 28, 2026 86% judged on-target in blind review
71Companies
10,533Contacts tracked
6,791Verified emails
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The 25 largest engagement letter software companies based in the United States

Ranked by team size
Top 25 of 71 engagement letter software companies based in the United States, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to engagement letter software companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 28, 20265,001-10,0008,156 contacts →

Indirect evidence

“Docusign brings agreements to life.”

Source: RevenueBase Database · checked Sep 28, 2026
2Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 28, 2026501-1,000859 contacts →

Indirect evidence

“Stand out with the top‑rated solution for creating, managing, tracking, and esigning every important document you handle.”

Source: RevenueBase Database · checked Sep 28, 2026
3Partial evidenceFremont, CA, United StatesHQ checked Sep 28, 2026501-1,000480 contacts →

Partial evidence

“Foxit is a software leader delivering a fast, secure, AI-powered document suite that brings greater control, speed, and value to the way people work with documents.”

Source: RevenueBase Database · checked Sep 28, 2026
4Indirect evidenceIrvine, CA, United StatesHQ checked Sep 28, 2026201-500220 contacts →

Indirect evidence

“KDAN (TPEx: 7737) is committed to providing a diverse range of AI-driven workflow and data solutions, including digital document management, eSignature, and data analytics…”

Source: RevenueBase Database · checked Sep 28, 2026
5Indirect evidenceAnn Arbor, MI, United StatesHQ checked Sep 28, 2026201-500140 contacts →

Indirect evidence

“SafeSend, part of Thomson Reuters, offers award-winning automation technology for tax and accounting firms to provide an unrivaled client experience.”

Source: RevenueBase Database · checked Sep 28, 2026
6Indirect evidenceHouston, TX, United StatesHQ checked Sep 28, 202651-20077 contacts →

Indirect evidence

“SmartVault is the leading provider of a secure, cloud-based document management and client portal platform purpose-built for accounting and tax professionals.”

Source: RevenueBase Database · checked Sep 28, 2026
7Indirect evidenceFranklin, TN, United StatesHQ checked Sep 28, 202651-20065 contacts →

Indirect evidence

“HubSync is an AI-powered, end-to-end tax and accounting workflow platform built exclusively for CPA firms.”

Source: RevenueBase Database · checked Sep 28, 2026
8Indirect evidenceNew York, NY, United StatesHQ checked Sep 28, 202651-20050 contacts →

Indirect evidence

“S-Docs is a document operations platform that helps thousands of organizations-from small shops to global enterprises-scale smarter.”

Source: RevenueBase Database · checked Sep 28, 2026
9Indirect evidenceRancho Cucamonga, United StatesHQ checked Sep 28, 202611-5041 contacts →

Indirect evidence

“Truss is the 1st agentic AI tax workflow platform built for modern CPA firms.”

Source: RevenueBase Database · checked Sep 28, 2026
10Indirect evidenceWilmington, DE, United StatesHQ checked Sep 28, 202611-5029 contacts →

Indirect evidence

“Certinal is the Trust, Consent & Compliance Platform built for healthcare.”

Source: RevenueBase Database · checked Sep 28, 2026
11Indirect evidenceWestwood, MA, United StatesHQ checked Sep 28, 202611-5021 contacts →

Indirect evidence

“Leaflet Corporation brings you the Leaflet® Platform™, the collaborative document and contract automation and management solution that changes the entire landscape of document…”

Source: RevenueBase Database · checked Sep 28, 2026
12Indirect evidenceBoston, MA, United StatesHQ checked Sep 28, 20261-1020 contacts →

Indirect evidence

“DocHub is a digital signing platform which enables individuals and businesses to annotate, markup, and sign documents collaboratively.”

Source: RevenueBase Database · checked Sep 28, 2026
13Indirect evidenceDover, DE, United StatesHQ checked Sep 28, 202611-5019 contacts →

Indirect evidence

“BoloSign is a cloud-based eSignature tool that enhances user experience with seamless signature integration on forms and PDFs.”

Source: RevenueBase Database · checked Sep 28, 2026
14Partial evidenceOgden, UT, United StatesHQ checked Sep 28, 202611-5017 contacts →

Partial evidence

“With over 20 years of experience, PDCflow software combines secure payments, esignatures, documents, and photo/file upload requests into simple, secure workflows.”

Source: RevenueBase Database · checked Sep 28, 2026
15Indirect evidenceRemote, United StatesHQ checked Sep 28, 202611-5015 contacts →

Indirect evidence

“Go paperless and transform your business with legally binding electronic signatures.”

Source: RevenueBase Database · checked Sep 28, 2026
16Indirect evidenceSeattle, WA, United StatesHQ checked Sep 28, 202611-5014 contacts →

Indirect evidence

“Melento is an online Contract Negotiation and Quote-to-Cash platform that allows users to create proposals, generate quotes, negotiate contracts, and bill invoices all on one…”

Source: RevenueBase Database · checked Sep 28, 2026
17Partial evidenceAustin, TX, United StatesHQ checked Sep 28, 20261,001-5,00012 contacts →

Partial evidence

“Upland FileBound is AI-enhanced workflow automation and secure document management software.”

Source: RevenueBase Database · checked Sep 28, 2026
18Indirect evidenceHauppauge, NY, United StatesHQ checked Sep 28, 202611-5012 contacts →

Indirect evidence

“eSigns understands your business process better, faster, and quicker than the rest of the world to ensure hassle-free and paperless workflow management.”

Source: RevenueBase Database · checked Sep 28, 2026
19Indirect evidenceWest Palm Beach, FL, United StatesHQ checked Sep 28, 202611-5011 contacts →

Indirect evidence

“Built by accountants for accountants, Mango Practice Management provides project management, time and billing, and secure file-sharing features that organize and modernize your…”

Source: RevenueBase Database · checked Sep 28, 2026
20Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 28, 20261-1011 contacts →

Indirect evidence

“Securely send and sign AI-powered agreements with collaborative workflows, automated reporting, dynamic invoicing, and free e-signature.”

Source: RevenueBase Database · checked Sep 28, 2026
21Partial evidenceLakewood Ranch, FL, United StatesHQ checked Sep 28, 202611-5010 contacts →

Partial evidence

“dbs Software and Services is a leading provider of SaaS and on-prem document management, eForms with workflows, and eSignature solutions for organizations of all sizes.”

Source: RevenueBase Database · checked Sep 28, 2026
22Indirect evidenceLas Vegas, NV, United StatesHQ checked Sep 28, 202611-509 contacts →

Indirect evidence

“Inenvi is a group of talented designers, developers, and technicians dedicated to developing brands, technologies, and products.”

Source: RevenueBase Database · checked Sep 28, 2026
23Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 28, 202651-2009 contacts →

Indirect evidence

“Dropbox Sign makes agreements easy with simple and secure eSignatures.”

Source: RevenueBase Database · checked Sep 28, 2026
24Strong evidenceFrisco, TX, United StatesHQ checked Sep 28, 20261-105 contacts →

Strong evidence

“Knuula is the end-to-end engagement letter solution.”

Source: RevenueBase Database · checked Sep 28, 2026
25Indirect evidenceAustin, TX, United StatesHQ checked Sep 28, 202611-504 contacts →

Indirect evidence

“Countersign makes e-signatures simple, affordable, and transparent.”

Source: RevenueBase Database · checked Sep 28, 2026

Showing 25 of 71 engagement letter software companies based in the United States

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Engagement letter software companies based in the United States at a glance

As of Sep 28, 2026
64.5%Verified-email coverage
148.4Average contacts per company
11-50Median size (employees)
5.6%Largest-city concentration · San Francisco
Sep 28, 2026Page data refreshed

Companies by employee count

1-10
17
11-50
33
51-200
11
201-500
3
501-1,000
4
1,001-5,000
2
5,001-10,000
1

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 71 companies.

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 engagement letter software companies, 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 “engagement letter software companies”. 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 engagement letter software companies), 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 engagement letter 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 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, 6,791 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 28, 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

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 engagement letter software companies, 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 engagement letter software companies are there based in the United States?

RevenueBase identified 71 engagement letter 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?

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

Which city has the most engagement letter software companies?

San Francisco leads with 4 headquartered companies, followed by Ann Arbor (2) and Austin (2).

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 6,791 verified decision-maker contacts tracked across these 71 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 28, 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 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.