Looking for a top JavaScript developer in Seattle?

If you're hiring a JavaScript developer to help you build or update a website that's responsive and interactive, consider the pros and cons of JavaScript as a programming language. Advantages include its speed because it's executed on the client-side; reduction in server load; and diverse functionality. Disadvantages to consider include security such as bugs on the client-side.

To assist you in your search for a partner, we’ve compiled this list of the top JavaScript development agencies in Seattle. Browse descriptions, feedback, and awards to find which can best suit your company’s needs. If you need more support, tell us about your project, and we'll match you with recommended companies.

List of the Best Seattle JavaScript Developers

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  • 2
    $10,000+
    250 - 999 Employees
    Olympia WA

    Celebrate Drupal is a web development and design firm in Seattle. It was founded in 2009, and its team of 8 helps clients with IT staff augmentation, custom software development, UI/UX design, and e-commerce development in addition to web design and development.

    Clients
    Hasbro Inc.
    Pod Consulting
    Fuse Ideas
    State of Georgia Health
    Industries
    Notable Project

    A networking nonprofit hired Celebrate Drupal after a member said that its website was not being used as effectively as possible. Celebrate Drupal manages the website's back end, keeps the design current, and provides updates and staff training.

    "If I have something I need them to work on, we're in constant contact with each other, and I never really had that with any other developer before. Their level of responsiveness is very high, even though we have a three-hour time difference. We're very cognizant of each other's work schedules, and they're very accommodating." - Finance & Technology Manager, Networking Nonprofit

  • 3
    $25,000+
    10 - 49 Employees
    Seattle WA

    Founded in 2010 in Seattle, Billberry is a software development studio creating custom software, web apps, and digital products in partnership with some of the world's biggest brands. They have a veteran team of fewer than 50 strategists, designers, and developers who work in partnership with clients to help them grow, innovate, and move their businesses forward. Clients include businesses of all sizes in various industries, including business services, consumer products and services, and financial services.

    Clients
    Days for Girls
    Snohomish County Public Utilities
    Impinj
    The Live You Can Save
    Industries
    Notable Project

    Bilberrry created and designed a completely new WordPress website for a government agency focused on fruit production and distribution. They also integrated a translator plug-in to ease content creation.

    “Bilberrry has done an impressive job at bringing their creativity into the project.”

  • 4
    $25,000+
    10 - 49 Employees
    Seattle WA

    Culture Foundry is a web agency founded in Seattle in 2010 with more than 10 employees. They specialize in digital strategy, web design, and web development solutions for small and mid-market firms in the fields of arts, IT, and financial services.

    Clients
    24 Hour Fitness
    Audinate
    Ballet Austin
    Belmont Stakes / NYRA
    Industries
    Notable Project

    Culture Foundry developed a website for a tech community and events group. The website was built with WordPress and was also optimized for SEO support. The group sees more and more traffic to the site each month.

    “Anytime issues came up, they were immediately responded to.” - Founder & CEO, Tech Community and Events Group

  • 5
    $10,000+
    10 - 49 Employees
    Seattle WA

    Helpful Human is a development agency based in Seattle. Since 2013, their team of 15 has been specializing in web design and development, mobile app development, and UX/UI design. They work primarily with small businesses in the information services and business services industries.

    Clients
    Rudy's
    naturewise
    Elm Coffee Roasters
    Holland America Line
    Industries
    Notable Project

    A tech startup hired Helpful Human for their design expertise. They conducted background research, made suggestions for a prototype test, and will assist with future phases. The client prides Helpful Human on being responsive. 

    "Their experience and expertise played a major part and they were thoughtful and insightful." – Owner, Technology Startup 

  • 6
    Undisclosed
    10 - 49 Employees
    Renton WA

    Modelit is a software development company that is located Uruguay with 50 professionals in the web development and programming industry. Since 2012, they have been working with clients as assets in the web development and IT consulting segments

    Clients
    Salesforce
    Amazon
    Build It Green
    Fair Trade USA
    Notable Project

    Modelit partnered with a tech company to manipulate already existing CRM beyond its typical configuration. They offered highly specialized developers to give the client a successful program and result.

    “They are very organized, and they really understand the process of custom software development. Our projects are usually quite large, and we need to break them down into smaller tasks. We use their project management tool, and whenever we have a need, they tell us how many hours each task will take. I really enjoy their organization and transparency.” – Program Manager, Technology Company

  • 7
    $5,000+
    50 - 249 Employees
    Seattle WA

    Forum One is a full-service digital design firm that was founded in 1997. The company has more than 100 employees in Alexandria, Va., Washington, D.C., and Seattle. Forum One offers web design, UX/UI design, web development, branding, and other digital services for mainly nonprofits and government agencies.

    Clients
    Smithsonian Institution (National Museum of African American History & Culture
    National Museum of Natural History and the National Zoo)
    Global Impact
    Patient Centered Outcomes Research Institute (PCORI)
    Industries
    Notable Project

    A museum was preparing for its opening and only had a simple website. Forum One built a robust Drupal 7 website that incorporated important educational and search features. Forum One continues to maintain the website and incorporates events happening at the museum.

    "We’re pleased with their work, and our audience has responded positively to the functionality, design, and usability ... They’re a very talented group and open to collaboration. We will continue our relationship with them and continue to improve upon it." - Chief Digital Officer, Museum

  • 8
    $5,000+
    2 - 9 Employees
    Monroe WA

    Efinitytech is a web design company located in Monroe, Wash. Founded in 1998, Efinitytech's team of around 5 employees specializes in web design, web development, and ecommerce development. Efinitytech's clients are primarily small businesses in the ecommerce, real estate, and consumer product spaces.

    Clients
    Safe Consulting
    Woodinville Florist
    Northwest Outdoor Lighting, Inc
    Barn Pros
    Industries
    Notable Project

    Efinitytech worked with a publishing group aiming to garner more web traffic, improve website security, and build a mobile app. In addition to providing these services, Efinitytech assisted with improving SEO and expanding payment options on the client's ecommerce website. The client planned to increase their investment with Efinitytech in the future.

    "We’ve had over 450% growth in the last two years. Our first website had a WordPress interface, which only had 5% of the functionality compared to Efinity Tech’s version. They built our website quickly, efficiently, and effectively." – CEO, Publishing Group

  • 9
    $25,000+
    2 - 9 Employees
    Seattle WA

    Northwest Independent Ruby Development is a digital agency based in Seattle. Since 2011, the small team of four has specialized in providing web and custom software development. 

    Clients
    University of Washington
    Avvo
    Whitepages
    Behavioral Tech
    Notable Project

    Northwest Independent Ruby Development was hired to create software for a mental health project. Because of their work, the software was easier to manage internally.

    "They [Northwest Independent Ruby Development] are good at translating to us what they need to do as a developer to make the program work."- Customer Service and Operations Manager, Mental Health Project

  • 10
    $10,000+
    2 - 9 Employees
    Seattle WA

    Black Antelope is a digital creative industry headquartered in Seattle. It was founded in 2009 and has expanded to additional locations in Sacremento, Calif. and London. Black Antelope has about 3 employees that serve a range of enterprise and small- to mid-sized businesses. Services include custom software development, web development, and web design. 

    Clients
    UC Berkeley (Berkeley, CA)
    UCSF (San Francisco, CA)
    Monterey Bay Aquarium (Monterey, CA)
    Fujitsu Laboratories Of America (Sunnyvale, CA)
    Industries
    Notable Project

    Black Antelope redeveloped a website on a unified Drupal CMS to improve performance. The system includes translation modules for different coding languages. Initially, they provided design services before a third-party vendor assumed that responsibility. Subsequently, they focused on SEO and increased web traffic significantly. The site's faster speed and new professional look significantly improve site rankings. 

    "Despite significant peaks of traffic at times, the site never went down. Black Antelope helped us with initial SEO implementations, giving us core advice for this area. We definitely saw an uptick in Google search results."  – Director of Web Development, Tech Company

     

  • 11
    $1,000+
    2 - 9 Employees
    Seattle WA

    Visualwebz is a digital design and marketing agency located in Renton, Wash., with under 10 employees. Founded in 2008, the company mainly provides web design and development, e-commerce development, SEO services, and content marketing using a variety of programs and systems.

    Clients
    TimeXtender
    Mitsubishi
    Fuso
    PGTAA
    Industries
    Notable Project

    A private equity firm hired Visualwebz to build a new website from scratch. Using Bluehost, the team developed and designed a website that met all requirements and added an interactive map feature, created a domain name, and set up various email addresses. Visualwebz efforts grew the client’s web presence, the site received positive feedback from users. The team was detailed and comprehensive in their approach to web development.

    “Their responsiveness is really important to us. They have other clients and projects, but we always felt like we were their only client.” — COO, Private Equity Firm

  • 12
    $5,000+
    10 - 49 Employees
    Seattle WA

    Hero Creative is a Seattle-based media production company founded in 2012. Their team of around 10 employees provides marketing strategy, branding, advertising and web design. They primarily serve enterprise clients in the advertising, hospitality and nonprofit industries.

    Clients
    Make-A-Wish Foundation
    University of Washington
    Leukemia and Lymphoma Society
    Northwest Motorsport
    Industries
    Notable Project

    A nonprofit hired Hero Creative as a visual storytelling partner. They offered professional photography, filming services and web development. The client praised their creativity, commitment and passion.

    “They’re fun, creative, and down to earth—and they love devising innovative solutions to our challenges.” – Vice President of Communications, Nonprofit
     

  • 13
    $5,000+
    2 - 9 Employees
    Shoreline WA

    VisionSnap is a design and development company based in Seattle, with an additional office in Phoenix, AZ. The team was founded in 1999. VisionSnap specializes in providing UX/UI design, web development, and web design services primarily for small and midmarket businesses.

    Clients
    Rulersmith
    GuerraWilson Group
    Valley National Bank of Arizona
    Midland Real Estate
    Industries
    Notable Project

    VisionSnap worked with this restaurant to build its website and take charge of its digital marketing campaigns. VisionSnap designed and developed the website to be more visually appealing with a high number of photos, ensured that it was optimized for Google searches, and implemented tracking capabilities.

    "The volume of emails, inquiries, and phone calls has doubled in the last couple of years." — Banquet Sales Manager, Restaurant

  • 14
    $5,000+
    10 - 49 Employees
    Seattle WA

    Conflare is a web development and design firm in Seattle. It was founded in 2004 and currently has 4 employees. Conflare provides web design and development, branding, digital strategy, and video production services mainly to small business clients.

    Clients
    Artisan Electric
    PhotoTC
    AME Commerce
    Foundry Law
    Industries
    Notable Project

    A jewelry company hired Conflare to update its Shopify website. Conflare built a new e-commerce website from scratch, including a custom "design your own ring" feature. It continues to perform site updates and add products. 

    "They’re honest. They’ve proven to be a very trustworthy partner, both initially and over the length of the project. They’re upfront with how they tackle the work." - Co-Founder, Jewelry Company

  • 15
    $10,000+
    10 - 49 Employees
    Medina WA

    A full-service digital design and development agency, Flower Press Creative Studio takes on mobile app, web, and custom software development projects. Founded in 2001, the small team of 6 is headquartered in Seattle and also has experience in UI/UX design.

    Clients
    Insurance Lounge
    Brown Bear Car Wash
    Geek Girl Careers
    World Perspectives
    Industries
    Notable Project

    A founder of a social meetup company needed help launching the business. Flower Press Creative Studio agreed to help, developing an iOS app and assisting with branding.

    “She was really good at taking my ideas and turning them into something usable. She’s easy to work with, as well as versatile. She has a way of remedying doubts clients might have about their ideas.” – Founder, Social Meetup App

  • 16
    $25,000+
    2 - 9 Employees
    Seattle WA

    Lunarbyte.io is a development agency based in Seattle. Since 2019, the 3-person team has built websites, custom software, and mobile apps for predominantly small businesses.  

    Clients
    Preflight Mitigator
    Dollar Flight Club
    Story Tellers for Change
    Protection Home Inspectio
    Industries
    Notable Project

    Lunarbyte.io developed payment systems, mailing solutions, and deliverability functionality for a flight deals platform. They also provided support with WordPress. The client's business more than doubled as a result. 

    "Everything they do is delivered well, and they aren’t stressed about the production process. Those are qualities you can’t buy." – COO, Flight Deals Platform

  • 17
    $1,000+
    10 - 49 Employees
    Redmond WA

    Designify is a web agency based in Redmond, Wash., and founded in 2017. With no more than 50 members, they specialize in web development, web design, and SEO solutions for small and mid-market businesses in the fields of business services, consumer products, and e-commerce.

    Clients
    Startline
    Chipmonk Consulting
    Center Source Inc
    Industries
    Notable Project

    Designify developed a WordPress website for a fitness company. The company needed a website to help better convert sales for their business. Designify developed a professional-looking platform that the company was satisfied with.

    “They understood all of the issues with the site without me having to tell them.” - CEO, Fitness Company

     

  • 18
    $1,000+
    10 - 49 Employees
    Seattle WA

    Digitegy is a digital agency that provides a mix of development and marketing services: software, web, and mobile app development, web design, SEO, PPC, and digital strategy. Founded in 2016, they have a small team of fewer than five employees.

    Notable Project

    A small bagel restaurant tasked Digitegy with designing and developing a website. Digitegy accepted the challenge, launching the project by getting to know the client's needs, such as the most important information to include on the site, branding, and features. After completing the website, Digitegy transformed it into an app, so users could choose how they interact with the bagel restaurant.

    "Digitegy frequently reaches out to us with suggestions of how to make the site better. They help us much more than any company that we’ve ever worked with." – Owner, Bagel Restaurant 

  • 19
    $1,000+
    2 - 9 Employees
    Seattle WA

     Headquartered in Seattle, Maintaingo is a development agency and site support service. The company was founded in 2016 and has under 10 employees. They specialize in web development, e-commerce, design, and SEO. 

    Clients
    Institute for Systems Biology
    WorkCare
    GLP Attorneys
    Louroe Electronics
    Notable Project

    Maintaingo managed development for an advertising agency that works with multiple clients. The team worked collaboratively with end clients to design and build full sites according to specific requirements. 

    "They’re excellent - always cheerful, always positive, always staying on top of everything. They’re very responsive and communicate effectively." – Project Manager, Advertising Agency

  • 20
    $1,000+
    2 - 9 Employees
    Tacoma WA

    Grinev Software is a development company based in Federal Way, Wash. Their team was founded in 2007 and has around 10 employees. They primarily provide mobile app, web, and e-commerce development. 

    Clients
    grinev.software
    Salesfolks
    truevirtualtours
    murav.ru
    Notable Project

    Grinev Software developed the frontend of an AWS-hosted sales firm's site. They created the tools and handled necessary customizations. The delivered work was a success and the project was productive. 

    "They were incredibly fun to work with. Life's too short to not work with people you like and respect." – Managing Director, Sales Firm

  • 21
    $1,000+
    2 - 9 Employees
    Seattle WA

    A digital marketer based in San Francisco, Randy McCabe offers SEO, PPC, and digital strategy services. They were founded in 2018.

    Clients
    Off Leash K9 Training London
    Notable Project

    Randy McCabe provided digital marketing services to a pet training company They offered SEO and PPC expertise to increase the company’s online presence. They successfully increased leads while decreasing spend overall.

    “Prior to the redesign, we would typically sell out 1-2 months in advance. We are now sold out about 4-5 months in advance.” — CEO, Pet Training Compan

  • 22
    $5,000+
    10 - 49 Employees
    Bellevue WA

    Truu Digital, a website development company, was established in 2012. The small Bellevue, Washington-based team provides web development, conversion optimization, CRM consulting and SI, digital strategy, and more.

    Industries
    Notable Project

    Truu Digital developed a website for a chiropractor practice. The team built and designed a new website with a more modern image.

    "They are up to date with technology, communicate well, and listen to your needs."

  • 23
    $25,000+
    50 - 249 Employees
    Bellevue WA

    Redtech is a custom software development firm. They are located in Bellevue, Washington and have a midsize team. Their services include custom software development, non-voice bpo/back office services, digital strategy, web development, and more. The agency was established in 1995.

    Notable Project

    Redtech provided BI and analytics for a software company. They redesigned a learning catalog and supported in understanding its current status.

    "Their subject matter expertise and professionalism were impressive."

  • 24
    $5,000+
    10 - 49 Employees
    Seattle WA

    Steelsmith Haus LLC is an internet marketing agency in Seattle. Founded in 2010, Steelsmith Haus has about 8 employees that work with a range of clients. Services include SEO, content marketing, web design, and email marketing services.

    Clients
    StacheClip
    Starving Students
    UC Berkeley
    StemGenex
    Industries
    Notable Project

    Steelsmith Haus worked with this personal training website to build its new website and supplement it with SEO and PPC capabilities. Steelsmith Haus collaborated with the client to capture the client's brand and implement the most effective marketing strategies.

    "They manage expectations well, knowing things can come up. Communication has been key to our relationship." — Owner, Personal Training Website

  • 25
    $10,000+
    2 - 9 Employees
    Olympia WA

    Tilladelse Marketing Agency is a full service marketing agency located in Olympia, Wash. Founded in 2018, they have a team of 3 employees who specialize in web design, PPC, e-commerce development, and web development for their clients
     

    Clients
    Bid Venues |
    McSwain CPA |
    Koelsch Construction |
    FarmGrit.com |
    Notable Project

    Tilladelse Marketing Agency provided web development and marketing services for an online auction platform. They built a WordPress website for the client, paying particular attention to the UX design. To promote the new site, they managed an email marketing campaign, provided SEO, and curated content on Facebook. The client’s new website has since received a positive response from users.

    “Our customers love the new website and its navigation. All of our feedback is positive.” – VP, Online Auction Platform
     

  • 26
    $1,000+
    2 - 9 Employees
    Edmonds WA

    Libnamic is a digital firm based in Puerto Real, Spain with over two employees. Founded in 2017, they offer web design, IT strategy consulting, and IT managed services for small and mid-market businesses in the fields of IT and government agencies, among others.

    Clients
    University of Seville
    Complutense University of Madrid
    Carlos III University of Madrid
    Spanish National Heritage
    Industries
    Notable Project

    Libnamic provided hosting services for a web dev company. The company wanted to improve the overall loading times of the sites that they manage. Libnamic improved many of the loading times by as much as 80%.

    “It is very easy to work with Libnamic as they have a standardized process for migrating and creating websites.” - Founder & SEO, Web Dev Company

  • 27
    $10,000+
    50 - 249 Employees
    Bellevue WA

    Virtuosity Consulting, a custom software development firm, was launched in 2008. They are located in Bellevue, Washington and Navi Mumbai, India and have a midsize team. Their services include custom software development, IT managed services, enterprise app modernization, web development, and more.

    Industries
    Notable Project

    A software company hired Virtuosity Consulting for staff augmentation. The team supplied qualified process-driven and self-motivated managers for early planning, daily execution, monthly releases, and more. 

    "The agency and the candidates they supplied really took ownership of the project."

  • 28
    $25,000+
    50 - 249 Employees
    Kirkland WA

    Heaven Solutions is an IT staff augmentation company founded in 2005. The company offers IT staff augmentation, application testing, custom software development, web development, and more and has a midsize team. The company is based in Kirkland, Washington; Iași, Romania; Bensheim, Germany and Il-Gżira, Malta.

    Industries
    Notable Project

    Heaven Solutions has aided the custom software development efforts for a streaming service provider's delivery system. They continue to support the platform by implementing enhancements and system integrations.

    "Heaven Solutions is a results-oriented team that strives to deliver optimal results."

  • 29
    $1,000+
    10 - 49 Employees
    Seattle WA

    DevelopersTroop- Website | App | Seo & Software development company is a custom software development company. Their small team is headquartered in Dhaka, Bangladesh and Flagstaff, Arizona. The agency specializes in custom software development, web development, mobile app development, search engine optimization, and more.

    Industries
    Notable Project

    An automotive company worked with DevelopersTroop to create a website. The team completed the site development with the help of UX/UI designers, developers, and the CEO. 

    "They are good enough on every point and I love all their processes and skills."

  • 30
    $5,000+
    50 - 249 Employees
    Redmond WA

    Citizen, Inc. Is a midsize UX company. Founded in 2005, the agency is based in Portland, Oregon and Redmond, Washington. Their team specializes in ux/ui design, mobile app development, web development, digital strategy, and more.

    Industries
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