Top Custom Software Development Companies in Seattle, WA
We ranked 6 custom software development companies in and around Seattle, WA on client reviews, how many are verified, service focus and profile completeness. Includes companies in nearby Bellevue and Kirkland. Updated October 2026. How rankings work
Partners that build software around how a business actually works, often replacing spreadsheets and a patchwork of subscriptions with one system the company owns.
- Rank 1
Seattle software firm building custom business applications, mobile apps and system integrations, and modernizing and supporting existing software.
No reviews yet
Seattle, WA
- Custom Software Development
- Mobile App Development
- API & Integration Development
- Rank 2
Seattle studio that plans, builds, deploys and operates custom software and applied AI systems for growing companies.
No reviews yet
Seattle, WA
- Custom Software Development
- AI & Automation
- Product Design & Development
- Rank 3
Kirkland, Washington software firm building HIPAA-compliant healthcare systems, EHR integrations and AI products for health-tech companies.
No reviews yet
Kirkland, WA
- Custom Software Development
- API & Integration Development
- AI & Automation
- Rank 4
Bellevue firm that pairs strategy, experience design, software, hardware and AI engineering to take products from concept to launch.
No reviews yet
Bellevue, WA
- Product Design & Development
- Custom Software Development
- AI & Automation
- Team
- 250-999 people
- Rank 5Down 2 from #3
Seattle UX modernization firm that researches, designs and builds updated systems, portals and workflows for service-driven organizations.
No reviews yet
Seattle, WA
- Product Design & Development
- UX/UI Design
- Custom Software Development
- Rank 6Down 2 from #4
Digital agency that plans, designs, develops, hosts and supports websites and web applications built on WordPress, Drupal and Django.
No reviews yet
Seattle, WA
- Web Development
- UX/UI Design
- Custom Software Development
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