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Most people don't notice excellent quality assurance (QA) testing. The funny thing is, that's how it should be.
When it's missing, your users can't help but notice. They run into bugs, crashes, broken buttons, and confusing workflows. If you're launching or updating your product, word-of-mouth will spread — but not the kind you hoped for.
To keep your users focused on your product, testing needs to be part of your process from the outset. Whether you're building a mobile app, a web platform, or something more complex, starting early helps your product perform at its best.
Working with a dedicated testing partner brings major advantages. Some companies handle QA in-house. But working with specialists is often more effective. QA shapes how products are built, tested, and improved from day one.
A few standout QA companies are leading the way. Before we get into who they are, let's talk about what QA actually means — and why it matters more than ever.
What is Quality Assurance Testing?
Quality assurance testing ensures your product works properly. It checks across platforms, devices, browsers, and real-world use cases. But it's more than just bug hunting. QA is about ensuring your app or site behaves as users expect it to.
QA testing uses both manual and automated methods to evaluate your product across different focus areas, like functionality, accessibility, localization, performance, and regression. The goal is to catch issues early and deliver a smoother, more reliable user experience.
Why QA Testing Matters
Small bugs can cause big problems, especially after launch.
The Consortium for Information & Software Quality estimates that poor software quality costs U.S. companies more than $2.4 trillion annually. That includes failed features, security issues, and tech debt that slows everything down.
QA improves product quality, reduces production issues, builds user trust, and keeps your release schedule on track.
The Advantage of Hiring a QA Testing Company
Some teams can manage QA in-house — if they have the time, tools, and talent. But building a complete QA process from scratch adds pressure. A dedicated partner brings real-device libraries, trained testers, and flexible workflows that help your team scale faster, without slowing down.
Here are 10 of the top QA testing companies developers often turn to when they need outsourced QA that goes beyond the basics.
1. PLUS QA
PLUS QA has focused exclusively on quality assurance since 2008. The company is 100% U.S.-based, with more than 70 analysts who work directly with clients to test mobile apps, websites, e-commerce platforms, and enterprise tools. PLUS QA operates a dedicated device lab with over 600 devices to support real-world testing at scale.
PLUS QA specializes in Accessibility testing since 2015 and has helped companies such as Airbnb, Nike and other large companies with their web and mobile accessibility..
What We Offer:
- Front end manual testing services
- Specialized in testing websites, desktop apps, IOT and mobile applications
- Real-device functionality and compatibility testing over 60 physical devices
- Dedicated resources
Headquarters: Portland, Oregon
Engagement & Pricing Model: Project-based and flexible, configured to suit each engagement
Website: plusqa.com
2. Applause
Applause is a global crowdtesting platform that matches clients with testers using real devices in real-world environments. Their network spans multiple countries and device types, providing extensive testing coverage across various use cases. Applause is a leader in the crowd testing space and connects organizations with a global community of professional testers who test real products in real-world conditions—across different devices, locations, and environments.
What They Offer:
- Usability, functional, localization, and payments testing
- Access to a global freelance testing network
Engagement & Pricing Model: Pricing varies by scope and complexity
Website: applause.com
3. QASource
QASource delivers QA solutions for tech, finance, legal, and healthcare. QASource combines offshore, nearshore, and onshore resources to deliver qa solutions to their costumers.
What They Offer:
- Manual and automated testing, API testing, DevOps support
- Team extensions that integrate into your development environment
Engagement & Pricing Model: Customized per-project or hourly pricing
Website: qasource.com
4. Qualitest
Qualitest is a global quality engineering and software testing company that provides end-to-end testing and quality assurance services. They specialize in functional, automation, performance, security, and AI-driven testing solutions across various industries, including finance, healthcare, retail, and technology.
What They Offer:
- Functional testing, cybersecurity, AI/ML testing
- Enterprise-focused strategy and QA frameworks
Engagement & Pricing Model: Outcome-based billing structured around large-scale testing needs
Website: qualitestgroup.com
5. Testlio
Testlio is a software testing company that provides managed testing services through a network of professional testers around the world. Testlio offers crowd testing services similar to what Applause and their network of testers. Testlio integrates closely with development teams and tools, enabling continuous testing within Agile and CI/CD workflows, and emphasizes real-world testing across multiple devices, platforms, and geographies.
What They Offer:
- Functional, usability, localization testing
- Flexible team scaling and test orchestration
Engagement & Pricing Model: Flexible pricing based on your product complexity and service levels
Website: testlio.com
6. QA Mentor
QA Mentor supports clients worldwide looking to expand QA capabilities or build new ones. They provide both technical testing and process improvement consulting services. QA Mentor provides a wide range of testing services from manual testing to test automation, performance and load testing and security testing. QAMentor also provides QA training, seminars and e-leanig.
What They Offer:
- Manual, automated, performance, and security testing
- QA strategy consulting, maturity assessments, and augmentation
Engagement & Pricing Model: Fluid options including fixed-price packages and pay-as-you-go models
Website: qamentor.com
7. Rainforest QA
Rainforest QA offers a cloud‑based, no‑code/visual test automation platform that allows teams—including non‑technical users—to create and run end‑to‑end web tests quickly, and integrates well into CI/CD workflows.
What They Offer:
- Automated functional testing with AI
- Scalable manual testing via virtual environments
Engagement & Pricing Model: Flexible usage- or contract-based pricing that scales with your usage and outcomes
Website: rainforestqa.com
8. QA Wolf
QA Wolf is a software testing platform that provides end-to-end test automation for web applications. It offers a fully managed service where tests are written, maintained, and executed by QA engineers on demand, helping development teams focus on building features rather than managing test scripts. QA Wolf supports JavaScript-based automated testing using frameworks like Playwright, integrates with CI/CD pipelines, and provides reporting and debugging tools. They integrate closely with development teams, focusing on test speed and simplicity.
What They Offer:
- Custom-built test suites and full test coverage
- Integration with CI/CD tools and detailed reporting
Engagement & Pricing Model: Per-test subscription pricing with ongoing maintenance and support
Website: qawolf.com
9. Sogeti
Sogeti, a Capgemini subsidiary, provides QA and engineering services with a strong emphasis on enterprise automation and DevOps integration. They serve clients in the finance, public sector, and manufacturing industries.
What They Offer:
- Test automation, performance testing, DevOps QA
- Pre-built frameworks for industry-specific QA
Engagement & Pricing Model: Managed service contracts crafted to enterprise needs across global deliveries
Website: sogeti.com
10. QualityLogic
QualityLogic specializes in QA for accessibility, smart energy, and print tech. They serve both public and private sector clients, providing a mix of manual and automated testing.
What They Offer:
- Manual and automated QA
- Testing for smart energy systems and accessibility compliance
Engagement & Pricing Model: Custom models offered based on the scope and nature of testing required—project or ongoing
Website: qualitylogic.com
Questions to Ask Before Choosing a QA Partner
Before hiring a QA company, it's helpful to clarify a few key points, especially if you're a new QA vendor. There's no one-size-fits-all. But asking the right questions can make a huge difference.
Ask yourself:
- What kind of product am I building? (Mobile app, web platform, desktop software, VR, etc.)
- What type of testing do I need? (Functional, performance, accessibility, compatibility, security)
- How frequently will testing occur? (Once, weekly, during every sprint?)
Ask the QA company:
- How does the partnership work? Will we have a dedicated project manager?
- Where are your testing teams located? How do you handle time zone or language differences?
- What are your security protocols for sensitive data?
- What bug tracking systems do you use, and can we integrate with ours?
- How often can we expect to hear from your team during a test cycle, and what types of updates or insights can we expect to receive?
- What is the technical experience level of your testers?
PLUS QA: Experienced & Onshore QA Testing Partner
Look for a QA team that understands your goals and fits into your workflow from day one.
At PLUS QA, we’ve spent more than 17 years partnering with developers, designers, and product teams to test digital products the right way. We offer manual and automated testing. Our services include accessibility, usability, and device compatibility. All testing is done on real devices by U.S.-based testers—no emulators, no guesswork.
We support clients of all sizes, from fast-moving startups to Fortune 100 enterprises. Whether you’re prepping for launch or scaling a product that’s already live, we’re ready to get up to speed quickly and deliver the answers you need.
We're here to test things — so your users don't have to.