Seattle businesses can choose from local development studios, global engineering providers with regional coverage, and consulting firms equipped for complex financial systems. The companies below cover banking applications, payment products, lending platforms, data engineering, cloud modernization, AI, and fintech-focused product design.
1. Itexus
Itexus builds custom financial software for banks, fintech startups, investment firms, lenders, insurers, and wealth management companies. Its team covers product discovery, UX design, architecture, engineering, quality assurance, cloud deployment, and ongoing support.
Typical projects include digital banking, payment processing, lending automation, investment platforms, and personal finance tools. Itexus also builds financial analytics and AI-assisted workflows. It fits teams that want a partner with deep financial domain knowledge, not a general-purpose software vendor. The company takes on new product concepts as well as modernization of existing financial infrastructure.
Key Facts
- Best for: Custom fintech products and financial platform modernization
- Core services: Fintech software development, product discovery, mobile development, AI, QA, and maintenance
- Specialization: Banking, lending, payments, investment technology, and financial analytics
- Location: Serves Seattle and the wider US market
- Notable strength: Dedicated focus on financial software engineering
Contact Information
- Website: itexus.com
- E-mail: moc.suxeti@ofni
- Facebook: www.facebook.com/itexus
- Twitter: x.com/ItexusSoft
- LinkedIn: www.linkedin.com/company/itexus
- Instagram: www.instagram.com/itexus.soft
- Address: 8, The Green, STE road, Dover, DE 19901, United States
2. Zazz
Zazz handles product strategy, interface design, mobile development, and custom software engineering. In fintech, it builds mobile banking apps, digital wallets, transaction tools, and investment products. It also delivers payment integrations and account management platforms.
The team covers security needs such as authentication, encryption, transaction monitoring, and access controls. It builds native iOS and Android apps, and cross-platform apps with Flutter and React Native. With a Seattle presence, Zazz suits businesses that want a regional product team for both customer experience and app engineering.
Key Facts
- Best for: Customer-facing fintech and mobile banking applications
- Core services: Product design, mobile apps, web platforms, integrations, and maintenance
- Specialization: Digital wallets, payments, investment tools, and account management
- Location: Seattle, Washington
- Notable strength: Product design and engineering under one delivery model
Contact Information
- Website: www.zazz.io
- E-mail: oi.zzaz@selas
- Facebook: www.facebook.com/Zazz.Official
- Twitter: x.com/Zazz_Official
- LinkedIn: www.linkedin.com/company/zazz-io
- Instagram: www.instagram.com/zazz.io
- Address: 500 Mercer St, Seattle, WA 98109, USA
- Phone: 1800-315-8144
3. Seattle Software Developers
Seattle Software Developers runs full-cycle custom software projects, from planning and architecture to launch and later optimization. It builds mobile apps, cloud software, enterprise platforms, and AI tools, and handles API development and system integration.
For financial organizations, the team can build internal workflow systems, customer portals, and reporting apps. It can also build products that connect to payment or data providers. Clients can choose managed project delivery or staff augmentation. The second option helps companies with an in-house tech team that need extra engineers.
Key Facts
- Best for: Locally managed custom software projects
- Core services: Custom software, mobile apps, cloud applications, AI, and integrations
- Project types: Customer platforms, enterprise systems, and internal applications
- Location: Bellevue and the Seattle metropolitan area
- Notable strength: Full-cycle delivery and staff augmentation options
Contact Information
- Website: seattlesoftwaredevelopers.com
- E-mail: moc.srepolevederawtfoselttaes@olleh
- Facebook: www.facebook.com/share/1NYQENWATX
- LinkedIn: www.linkedin.com/company/seattle-software-developers
- Instagram: www.instagram.com/seattle.software.developers
- Address: 4 102nd Ave NE Bellevue, WA 98004
- Phone: (425) 307-9066
4. Jelvix
Jelvix builds financial software for digital banks, payment processors, lenders, investment businesses, and other financial organizations. Its work includes banking systems, payment software, lending platforms, and risk management tools. It also covers data analytics, AI, and blockchain development.
Jelvix can deliver a full product or provide a dedicated engineering team for an existing roadmap. It also offers enterprise integration, legacy modernization, QA, DevOps, and technical consulting. The company is a better match for technically complex products than for simple informational websites or lightweight prototypes.
Key Facts
- Best for: Complex financial platforms and dedicated development teams
- Core services: Enterprise software, mobile apps, AI, data engineering, QA, and DevOps
- Specialization: Digital banking, payments, lending, risk, and investment technology
- Location: Seattle market coverage
- Notable strength: Broad engineering capabilities for regulated financial products
Contact Information
- Website: jelvix.com
- E-mail: moc.xivlej@olleh
- Facebook: www.facebook.com/JelvixCompany
- Twitter: x.com/jelvix
- LinkedIn: www.linkedin.com/company/jelvix
- Instagram: www.instagram.com/jelvix
- Address: Kaupmehe tn 7, 10114 Tallinn, Estonia
- Phone: +12405075471
5. Mobcoder
Mobcoder builds web, mobile, SaaS, AI, and data-driven applications from Seattle and other delivery centers. Its banking and finance apps handle account access, transactions, payments, and digital customer experiences.
Besides engineering, Mobcoder offers UI/UX design, business analysis, quality assurance, DevOps, analytics, and post-launch maintenance. It can cover more of the product lifecycle than a contractor that only writes code. Businesses get regular US-based coordination along with access to a larger distributed development team.
Key Facts
- Best for: Mobile-first fintech products
- Core services: Mobile apps, web development, SaaS, AI, analytics, QA, and DevOps
- Industries: Banking and finance, healthcare, automotive, and consumer services
- Location: Seattle, Washington
- Notable strength: Cross-platform product development
Contact Information
- Website: mobcoder.com
- E-mail: moc.redocbom@selas
- Facebook: www.facebook.com/mobcoderinc
- Twitter: x.com/mobcoderinc
- LinkedIn: www.linkedin.com/company/mobcoder-llc
- Instagram: www.instagram.com/mobcoderinc
- Address: 11245 35th Avenue SW, Seattle
- Phone: +16723807141
6. SDLC Corp
SDLC Corp builds custom platforms for digital banks, credit unions, payment teams, and financial institutions. Its banking work covers customer portals, core workflows, payment modules, system integrations, and operational applications.
The company also offers custom software, artificial intelligence, cloud engineering, ERP implementation, blockchain, mobile development, and legacy modernization. That range helps when a fintech project goes beyond one app and needs back-office automation or links to enterprise systems. SDLC Corp works through a distributed delivery model and serves clients in Seattle and other US markets.
Key Facts
- Best for: Banking platforms and enterprise financial workflows
- Core services: Custom software, AI, cloud, ERP, blockchain, and mobile development
- Specialization: Banking portals, payments, integrations, and process automation
- Location: Serves Seattle remotely
- Notable strength: Combination of fintech engineering and enterprise systems work
Contact Information
- Website: sdlccorp.com
- E-mail: moc.procclds@selas
- Facebook: www.facebook.com/SDLCcorp
- Twitter: x.com/sdlccorp
- LinkedIn: www.linkedin.com/company/sdlccorp
- Address: 2457 Kane Lane, Batavia, Illinois 60510, USA
- Phone: +15106306507
7. UpTop
UpTop is a Seattle UX and digital product firm that works with technology-enabled service organizations, including financial services companies. It modernizes customer experiences, internal systems, transactional interfaces, and complex digital workflows.
The team does research, product strategy, interface design, prototyping, and application development. UpTop is a good option when usability and clear workflows matter as much as the code itself. Financial organizations with aging portals or hard-to-use internal tools may get more from its modernization work than from a typical new app build.
Key Facts
- Best for: Fintech UX modernization and complex service workflows
- Core services: UX research, product strategy, interface design, and application development
- Specialization: Transactional experiences and technology-enabled services
- Location: Seattle, Washington
- Notable strength: Simplifying complicated financial interfaces and workflows
Contact Information
- Website: www.uptopcorp.com
- E-mail: moc.procpotpu@ofni
- LinkedIn: www.linkedin.com/company/uptopcorp
- Address: 255 S King St Suite 800 Seattle WA 98104
- Phone: (206) 521-5700
8. ThirstySprout
ThirstySprout helps fintech businesses build dedicated engineering teams and hire individual technical specialists. The Seattle company uses an AI-assisted platform to source and vet developers across many technical skills.
It does not work like traditional project outsourcing. Clients use ThirstySprout to grow an existing fintech team, fill a hard-to-hire technical role, or set up a managed product group. The model works best when leadership and product requirements are already in place but engineering capacity is short.
Key Facts
- Best for: Fintech staff augmentation and dedicated teams
- Core services: Engineering recruitment, contract staffing, offshore staffing, and managed teams
- Specialization: Technical talent for fintech, AI, healthcare, and ecommerce
- Location: Seattle, Washington
- Notable strength: Flexible access to vetted engineering specialists
Contact Information
- Website: www.thirstysprout.com
- Facebook: www.facebook.com/thirstysprout
- Twitter: x.com/thirstysprout
- LinkedIn: www.linkedin.com/company/thirstysprout
- Instagram: www.instagram.com/thirstysprout
9. Techlusion
Techlusion builds fintech software for banks, credit unions, startups, and financial product teams in the Seattle market. Its work includes payment systems, digital lending, KYC and AML workflows, and fraud monitoring. It also builds financial dashboards, open banking integrations, and AI-assisted risk scoring.
Projects move through discovery, architecture, engineering, deployment, and ongoing support. Because Techlusion handles compliance-sensitive workflows, it fits serious financial applications better than a general mobile development shop. Buyers should still confirm certifications and control requirements during vendor assessment.
Key Facts
- Best for: Compliance-aware fintech applications
- Core services: Product development, integrations, cloud engineering, AI, and support
- Specialization: Payments, lending, onboarding, fraud monitoring, and open banking
- Location: Serves Seattle, Washington
- Notable strength: Focus on financial security and regulatory workflows
Contact Information
- Website: techlusion.io
- E-mail: oi.noisulhcet@ofni
- LinkedIn: www.linkedin.com/company/techlusion
- Instagram: www.instagram.com/techlusion_it
- Phone: +1-425-773-9055
10. NGS Solution
NGS Solution sells custom software development to Seattle organizations, including financial institutions, fintech startups, and larger enterprises. It builds web and mobile apps, cloud platforms, and AI, and handles system modernization and integration.
In fintech, the company builds secure financial applications and operational software, not only consumer-facing interfaces. That can include dashboards, transaction workflows, internal management tools, and integrations with external services. NGS Solution fits projects that need a broad outsourced engineering team and a conventional full-cycle development process.
Key Facts
- Best for: Custom fintech and business software
- Core services: Web development, mobile apps, cloud, AI, integrations, and modernization
- Project types: Financial platforms, dashboards, portals, and internal systems
- Location: Serves Seattle, Washington
- Notable strength: Broad custom development coverage
Contact Information
- Website: ngssolution.com
- E-mail: moc.noitulossgn@ofni
- Facebook: www.facebook.com/people/NGS-Solution
- Twitter: x.com/ngssolution1
- LinkedIn: www.linkedin.com/company/ngssolution
- Instagram: www.instagram.com/ngs.solution
- Address: 4400 State Hwy 121, Lewisville, TX 75056, United States
- Phone: +1 (972) 474-3919
11. Concetto Labs
Concetto Labs builds mobile and web apps for Seattle businesses. For financial products, it can add secure transactions, multi-currency features, analytics, and payment integrations. The company works with native mobile technologies as well as Flutter and other cross-platform frameworks.
It also offers AI, cloud applications, business intelligence, Microsoft Power Platform, and enterprise software. Concetto Labs is a practical choice for a mobile-first financial app that may later need reporting, workflow automation, or admin tools.
Key Facts
- Best for: Cross-platform fintech and payment applications
- Core services: Mobile apps, web software, AI, cloud, and business intelligence
- Technologies: Flutter, iOS, Android, Microsoft Power Platform, and web frameworks
- Location: Serves Seattle, Washington
- Notable strength: Mobile development combined with business automation capabilities
Contact Information
- Website: www.concettolabs.com
- E-mail: moc.sbalottecnoc@ofni
- Facebook: www.facebook.com/concettolabs
- Twitter: x.com/concettolabs
- LinkedIn: www.linkedin.com/company/concetto-labs-private-limited
- Instagram: www.instagram.com/concettolabs
- Address: 7289 W Harrison Street Chicago, IL 60612, USA
- Phone: 1(903)200-8801
12. Bilberrry
Bilberrry is a Seattle digital product and software development company. It builds web and mobile apps for organizations with complex technology and financial data needs. Its services include custom software, app modernization, UX/UI design, web and mobile development, DevOps, and digital product strategy. In fintech, it built a financial data platform for the Washington State Auditor's Office. It also built a scalable rate calculator platform for a national title insurance underwriter. Both projects involved financial data, complex business rules, secure architecture, and user-facing financial tools. Bilberrry suits organizations that want a Seattle partner for both product design and custom software engineering.
Key Facts
- Best for: Financial data platforms and custom fintech applications
- Core services: Custom software, web and mobile development, application modernization, UX/UI, and DevOps
- Specialization: Financial data, insurance technology, enterprise applications, and digital products
- Location: Seattle, Washington
- Notable strength: Combining product design, software engineering, and experience with financial technology projects
Contact Information
- Website: bilberrry.com
- E-mail: moc.yrrreblib@ofni
- Address: 600 1st Ave, Suite 413 Seattle, WA 98104
- Phone: 206.818.7436
13. Akvelon
Akvelon is a software engineering and technology consulting company headquartered in Bellevue, close to Seattle. Financial businesses can use it for custom applications, data platforms, cloud services, AI, or extended development teams.
Its work spans software engineering, mobile development, business intelligence, CRM, quality assurance, and DevOps. Akvelon fits fintech organizations that need engineering depth or more capacity for an existing product, rather than a branding-led digital agency.
Key Facts
- Best for: Enterprise fintech engineering and team extension
- Core services: Custom software, data engineering, AI, mobile apps, QA, and DevOps
- Project types: Enterprise platforms, cloud systems, analytics, and integrations
- Location: Bellevue, Washington
- Notable strength: Access to a sizable distributed engineering organization
Contact Information
- Website: akvelon.com
- E-mail: moc.nolevka@ofni
- Twitter: x.com/AkvelonInc
- LinkedIn: www.linkedin.com/company/akvelon
- Address: 3120 139th Avenue SE Suite 100 Bellevue, WA 98005
- Phone: +1(206)905-4626
14. Persistent Systems
Persistent Systems serves the Seattle area from its Bellevue office. It provides digital engineering to banks, financial institutions, insurers, and other enterprise clients. Its financial services work covers cloud modernization, data and analytics, digital banking, payments, automation, and customer experience systems.
The company is built for larger transformation programs, especially those with legacy applications, multiple vendors, or enterprise platforms. Startups that need a small MVP team may find smaller studios easier to work with. Established financial organizations, by contrast, can benefit from Persistent's scale and integration experience.
Key Facts
- Best for: Enterprise banking and financial modernization
- Core services: Digital engineering, cloud, data, AI, automation, and application management
- Specialization: Banking, payments, insurance, and financial services technology
- Location: Bellevue, Washington
- Notable strength: Large-scale modernization and systems integration
Contact Information
- Website: www.persistent.com
- E-mail: moc.tnetsisrep@ofni
- Facebook: www.facebook.com/PersistentSystems
- Twitter: x.com/Persistentsys
- LinkedIn: www.linkedin.com/company/persistent-systems
- Instagram: www.instagram.com/persistent_systems
- Address: 3380, 146th Place SE Suite 220, Bellevue WA – 98007
- Phone: +1-650-481-9180
15. Slalom
Slalom is a Seattle-headquartered firm that combines business consulting with technology implementation. Its teams work on cloud platforms, data engineering, artificial intelligence, customer experience, application development, and organizational transformation.
In financial services, Slalom can help with digital banking initiatives, analytics programs, cloud migrations, internal workflow modernization, and customer-facing product improvements. It suits organizations that want strategic consulting along with implementation, not buyers looking only for an outsourced coding team. Its local roots also make in-person stakeholder workshops and cross-team planning easier.
Key Facts
- Best for: Strategy-led financial technology transformation
- Core services: Technology consulting, application development, cloud, data, AI, and experience design
- Specialization: Enterprise transformation across regulated and data-intensive industries
- Location: Seattle, Washington
- Notable strength: Combining business strategy with technical implementation
Contact Information
- Website: www.slalom.com
- Twitter: x.com/slalom
- LinkedIn: www.linkedin.com/company/slalom-consulting
- Instagram: www.instagram.com/slalomconsulting
- Address: Slalom Hawk Tower 255 S King St Suite 1800 Seattle, Washington 98104
Conclusion
Seattle offers a varied fintech development market, from product-focused studios building mobile banking and payment apps to larger engineering partners handling cloud migration, data platforms, and legacy modernization. The right fit depends less on company size and more on experience with the exact financial workflows, integrations, and regulatory demands involved.
Before making a decision, compare relevant fintech projects, security practices, delivery ownership, and post-launch support. A strong development partner should understand that financial software is not simply another app. Reliability, accurate data handling, clear user journeys, and long-term maintainability all carry real weight.