Company lists · Data refreshed September 2026
Top 25 Custom software companies based in Seattle, United States
RevenueBase identified 64 custom software companies headquartered in Seattle, United States as of September 2026 and tracks 480 professional contacts across them, including 153 with verified work emails. New York is the largest hub.
This list covers custom software companies 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 24, 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 custom software companies based in Seattle, United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 135 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 2 | 38 contacts → | ||||
Indirect evidence “Spiderbox Design - Transforming businesses worldwide with innovative digital solutions since 2011.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 3 | 28 contacts → | ||||
Partial evidence “Palador has provided successful enterprise solutions and strategic initiatives for mobility, app and web development and data and software integration since 2005.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 4 | 25 contacts → | ||||
Partial evidence “At pubGENIUS we build software that helps great ideas become real products.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 5 | 25 contacts → | ||||
Strong evidence “NewNormal builds custom software and lasting partnerships Since 2012 we’ve helped clients turn ideas into products that scale.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 6 | 13 contacts → | ||||
Partial evidence “What sets GenUI apart is an end-to-end product focus throughout all our experience design and software development services.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 7 | 13 contacts → | ||||
Strong evidence “iTrellis is a Custom Software and Systems Integration consultancy located in Seattle, WA.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 8 | 12 contacts → | ||||
Partial evidence “Qubitsoft is an innovative and creative company that aims to meet its clients’ demands and provide original software solutions.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 9 | 12 contacts → | ||||
Strong evidence “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: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 10 | 7 contacts → | ||||
Strong evidence “We build custom business software solutions that scale with companies and help streamline business processes and also specialize in NetSuite build/implementation for larger…” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 11 | 7 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 12 | 6 contacts → | ||||
Indirect evidence “Pythonwise Inc is leading provider of Information Technology consulting and business process services.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 13 | 4 contacts → | ||||
Partial evidence “We create and deploy tailor-made software solutions aimed at enhancing efficiency and optimizing operations for a diverse range of clients, spanning individuals, businesses…” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 14 | 4 contacts → | ||||
Partial evidence “Cogenix offers business consulting, application development and software integration services to our client base.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 15 | 4 contacts → | ||||
Partial evidence “Zaifworks is software development and cloud consulting firm that specializes in healthcare, real-estate and it services industries.* We transform, deploy and support what you are…” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 16 | 3 contacts → | ||||
Partial evidence “We are your software team for hire: four industry veterans with decades of cross-platform experience who have worked together for over a decade to launch products, run agencies…” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 17 | 3 contacts → | ||||
Indirect evidence “At Assemble, our people are the source of our success.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 18 | 3 contacts → | ||||
Indirect evidence “A boutique consulting firm based in Seattle, WA with offices in Orange County, CA specializing in Mobile App Development and Integration of Enterprise systems.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 19 | 2 contacts → | ||||
Strong evidence “WebOnyx is a software development company that specializes in building custom software.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 20 | 2 contacts → | ||||
Strong evidence “Established in 2008 as a advertising & financial software consulting firm, DEV.co brings brings over 12 years of successful leadership to custom software development projects…” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 21 | 1 contacts → | ||||
Indirect evidence “Buddio Tech build mobile apps.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 22 | 1 contacts → | ||||
Partial evidence “Inner Product builds great software for the enterprise.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 23 | 1 contacts → | ||||
Partial evidence “We take a lean, cost-effective approach to helping small-medium businesses (and the occasional enterprise) ship software that addresses acute needs and delivers immediate value.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 24 | 1 contacts → | ||||
Partial evidence “We are Software Engineers that are passionate about converting great ideas into unique and reliable software solutions that helps the business growth.” Source: RevenueBase Database · checked Sep 24, 2026Thanks. The Data Team will review it. | |||||
| 25 | 1 contacts → | ||||
Strong evidence “DB Web Forge is a full-service web and software development company with over 14 years of experience that specializes in building custom websites, apps, and software solutions for…” Source: RevenueBase Database · checked Sep 24, 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: custom software companies. 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 custom software companies.
- Partial evidence
- Its own public description names part of custom software companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name custom software companies. 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 64 custom software companies based in Seattle, United States
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Custom software companies based in Seattle, United States at a glance
As of Sep 24, 2026Companies by employee count
Email recency for this list is measured across the whole United States list rather than for Seattle, so it is reported there. Company counts and contact totals on this page are exact for Seattle, over 64 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 custom 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 Seattle, United States whose own description of what they do matches “custom 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 custom 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 custom software companies, 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 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, 153 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 24, 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.
Custom software companies by metro in the United States
- Custom software companies in New York439
- Custom software companies in Austin284
- Custom software companies in Houston198
- Custom software companies in Sheridan172
- Custom software companies in Miami169
- Custom software companies in Los Angeles168
- Custom software companies in Chicago162
- Custom software companies in Dallas157
- Custom software companies in San Francisco154
- Custom software companies in Atlanta127
- Custom software companies in San Diego91
- Custom software companies in Irving84
- Custom software companies in Denver82
- Custom software companies in Irvine79
- Custom software companies in Orlando79
- Custom software companies in Boston77
- Custom software companies in Dover77
- Custom software companies in Wilmington75
- Custom software companies in San Jose70
- Custom software companies in Tampa70
- Custom software companies in Seattle64
- Custom software companies in Alpharetta62
- Custom software companies in Plano62
- Custom software companies in Portland61
- Custom software companies in Frisco60
- Custom software companies in Charlotte48
- Custom software companies in Phoenix47
- Custom software companies in Las Vegas45
- Custom software companies in Minneapolis42
- Custom software companies in Newark40
- Custom software companies in Columbus39
- Custom software companies in Washington39
- Custom software companies in San Antonio38
- Custom software companies in Jacksonville37
- Custom software companies in Fort Lauderdale36
- Custom software companies in Philadelphia34
- Custom software companies in Richmond34
- Custom software companies in Santa Clara34
- Custom software companies in Scottsdale34
- Custom software companies in Cheyenne33
- Custom software companies in Herndon33
- Custom software companies in Raleigh33
- Custom software companies in Fremont32
- Custom software companies in Sunnyvale32
- Custom software companies in Arlington30
- Custom software companies in St Petersburg30
- Custom software companies in Albuquerque29
- Custom software companies in Bellevue29
- Custom software companies in Columbia29
- Custom software companies in Cumming29
- Custom software companies in Edison29
- Custom software companies in Lewes29
- Custom software companies in Pleasanton29
- Custom software companies in Cincinnati28
- Custom software companies in Salt Lake City28
- Custom software companies in Sacramento27
- Custom software companies in Indianapolis26
- Custom software companies in Boulder25
- Custom software companies in Jersey City25
- Custom software companies in Nashville25
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 custom 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 custom software companies are there based in Seattle, United States?
RevenueBase identified 64 custom software companies 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 custom software companies?
New York leads with 439 headquartered companies, followed by Austin (284) and Houston (198).
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 153 verified decision-maker contacts tracked across these 64 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 24, 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.
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