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Company lists · Data refreshed September 2026

Top 25 Platform building firms based in Seattle, United States

Compiled by the RevenueBase Data Team Data refreshed Sep 5, 2026 124 companies tracked

RevenueBase identified 124 platform building firms headquartered in Seattle, United States as of September 2026 and tracks 1,000 professional contacts across them, including 301 with verified work emails. New York is the largest hub.

This list covers platform building firms headquartered in Seattle, 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 5, 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 5, 2026 86% judged on-target in blind review
124Companies
1,000Contacts tracked
301Verified emails
Unlock all 124 companies Free signup · no credit card · 500 free credits

The 25 largest platform building firms based in Seattle, United States

Ranked by team size
Top 25 of 124 platform building firms based in Seattle, United States, ranked by team size, largest first. Data refreshed Sep 5, 2026. Evidence rates how directly each company's own description names platform building firms: 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
White Rabbit GroupIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202651-200135

“White Rabbit Group is a software development agency with a highly diverse and creative team that takes an idea through development and into scale.”

Source: company website · checked Sep 5, 2026
2
Ukad Umbraco, Optimizely And Azure Solution PartnerIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 2026201-500123

“UKAD is a helping companies extend engineering capacity and deliver complex solutions with predictable outcomes.”

Source: company website · checked Sep 5, 2026
3
RhombuzIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5063

“Rhombuz is a new-age design company, where design thinking meets data science to create products with measurable impact.”

Source: company website · checked Sep 5, 2026
4
EnvorsoIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202651-20051

“At Envorso, we specialize in guiding businesses through the complexities of modern engineering, software, and digital transformation.”

Source: company website · checked Sep 5, 2026
5
BilberrryIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5031

“We design and develop digital products and online experiences that help our clients grow, innovate, and transform.”

Source: company website · checked Sep 5, 2026
6
Bonsai Media GroupIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5029

“Bonsai Media Group is a digital advertising agency headquartered in Seattle.”

Source: company website · checked Sep 5, 2026
7
Efelle Creative, Digital Marketing AgencyIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5024

“efelle is an internationally recognized ecommerce & digital marketing agency based out of Seattle, Washington, delivering highly functional and engaging websites, applications…”

Source: company website · checked Sep 5, 2026
8
Culture FoundryIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5016

“Websites and web applications.”

Source: company website · checked Sep 5, 2026
9
GENUIIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5013

“What sets GenUI apart is an end-to-end product focus throughout all our experience design and software development services.”

Source: company website · checked Sep 5, 2026
10
Mentor Creative GroupIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-1013

“Founded in 2014 as a digital creative agency of one, Mentor now has an entire team of creatives and developers along with offices in Seattle, WA and Miami, FL.”

Source: company website · checked Sep 5, 2026
11
LunarbyteIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-1012

“Lunarbyte is a custom software and product development firm trusted by teams across industries to deliver dependable, scalable software solutions that drive real business results.”

Source: company website · checked Sep 5, 2026
12
Foundry InteractiveIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-5011

“We build, market and optimize websites that connect customers and businesses in ways that are both meaningful and measurable.”

Source: company website · checked Sep 5, 2026
13
Seamonster StudiosIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-109

“Based in Seattle, WA, SeaMonster Studios is a lean and limber group of designers, developers, marketers, team players, technologists, and strategists.”

Source: company website · checked Sep 5, 2026
14
Research & DesignIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-509

“Research & Design is a design and technology firm.”

Source: company website · checked Sep 5, 2026
15
L4 Digital, A Globant CompanyIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202651-2008

“L4 Digital was founded in 2008 with the belief that great people build great products.”

Source: company website · checked Sep 5, 2026
16
Moby, INCIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-508

“Moby is a digital agency that design and builds useful, easy to understand products that help our clients and partners solve tough challenges in creative ways.”

Source: company website · checked Sep 5, 2026
17
Catch Design StudioIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-108

“Using creativity, insight and passion, we apply the principles of good design to brand development, website design and production, & commercial interior architecture, creating…”

Source: company website · checked Sep 5, 2026
18
Blue Rooster INCIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-507

“Blue Rooster is a modern digital agency driving Strategy, UX Design and Technology for today's enterprise.”

Source: company website · checked Sep 5, 2026
19
Helpful HumanIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-507

“Helpful Human strategically cooperates with our clients to design and build digital products that bring people together.”

Source: company website · checked Sep 5, 2026
20
Montana Banana WEB Design & DevelopmentIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-106

“Montana Banana is a Seattle-based web development company specializing in e-commerce integrations, user-friendly shopping experiences, web accessibility, and mobile apps.”

Source: company website · checked Sep 5, 2026
21
Conflare Brand Design And WEB DevelopmentIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-106

“From logo and identity design to digital strategy and web development, Conflare is a creative studio of passionate makers.”

Source: company website · checked Sep 5, 2026
22
Alpha EncodedIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-106

“Based in the tech-centric city of Seattle, Alpha Encoded stands at the forefront of digital innovation.”

Source: company website · checked Sep 5, 2026
23
Hard RefreshIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-105

“Better for business.”

Source: company website · checked Sep 5, 2026
24
Lightboard, INCIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 202611-505

“Lightboard is a modern design agency, built from the ground up around software.”

Source: company website · checked Sep 5, 2026
25
Dupla StudiosIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261-104

“Dupla Studios is a user experience and digital product studio based in Seattle, WA.”

Source: company website · checked Sep 5, 2026

Showing 25 of 124 platform building firms based in Seattle, United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 301 reachable decision-makers.

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Platform building firms based in Seattle, United States at a glance

As of Sep 5, 2026
1-10Median size (employees)
New YorkLargest hub · 801 HQs
Contacts with mobile numbers
Sep 5, 2026Data refreshed

Companies by employee count

1-10
73
11-50
37
51-200
11
201-500
1
501-1,000
1
5,001-10,000
1

Email recency for this list is measured across the whole United States list rather than this city, so it is reported there. Company counts and contact totals on this page are exact for Seattle, over 124 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 platform building firms, 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 Seattle, United States whose own description of what they do matches “platform building firms”. 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 platform building firms, and records with no verified work email. Companies headquartered outside Seattle 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, 301 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 5, 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.

Platform building firms by metro in the United States

Frequently asked

How many platform building firms are there based in Seattle, United States?

RevenueBase identified 124 platform building firms headquartered in Seattle, 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?

White Rabbit Group, headquartered in Seattle, tops this list with the largest team on record.

Which city has the most platform building firms?

New York leads with 801 headquartered companies, followed by Austin (358) and Los Angeles (354).

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 301 verified decision-maker contacts tracked across these 124 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 5, 2026.

Ready to reach these companies? Verified emails and direct dials for all 124 platform building firms based in Seattle, United States. Start with a free account, no credit card.

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Related lists

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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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