Functional Testing Services

Functional Testing Services – Improve Application Performance With Comprehensive Testing

Transform the performance of your code, apps, and platforms with Toptal’s Functional Testing Services. Our dedicated teams assess critical requirements, apply end‑to‑end testing strategies, and deliver actionable insights that reduce errors, improve quality, and support seamless user experiences.

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Clients Served

35,000+

Total Vetted Professionals

30,000+

Toptal Total Projects Delivered

85,000+

Years in Business

15+

TRUSTED BY LEADING BRANDS

Our Services

Toptal Functional Testing Services

Toptal’s Functional Testing Services support product quality throughout the development cycle. We apply proven testing methodologies—including unit, integration, and user acceptance testing—to verify software functionality, reduce testing costs, and meet customer expectations through a structured, efficient approach.

Unit Testing

Test individual components early in the development cycle to identify and resolve functional issues at the source.

Integration Testing

Evaluate interactions between modules to confirm seamless integration and consistent behavior across components.

System Testing

Test end-to-end workflows to confirm your software meets all functional and business requirements.

Smoke Testing

Perform preliminary checks on core functionality to verify basic operations before advancing to more detailed testing phases.

User Acceptance Testing

Validate your product against functional requirements to confirm it meets stakeholder and user expectations.

Regression Testing

Revalidate functionality after updates to ensure consistent performance and avoid introducing new issues.

Manual Functional Testing

Leverage manual testing to uncover edge cases and functionality gaps that automated tests may miss.

Automated Functional Testing

Run automated scripts to accelerate testing cycles, improve accuracy, and support continuous delivery.

Exploratory Testing

Discover potential issues through unscripted testing that simulates real-world user behavior.

Interface Testing

Assess how different software components communicate through APIs to confirm data flows and functionality.

Usability Testing

Evaluate touchpoints and design elements to improve user satisfaction and create a seamless user experience.

Sanity Testing

Verify that specific functions work as expected after minor code changes or fixes, prior to full-scale testing.

Looking for guidance about the perfect functional testing service for your needs?

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PARTNERSHIP THAT WORKS

How We Deliver Functional Testing Services

Our functional testing experts, with experience at leading companies, develop and deploy tailored solutions to meet your business needs and unique industry demands for sustainable results and long-term success.

Discover

A leader from our team works with you to understand your business challenges, pain points, and strategic goals to uncover new opportunities and identify the options to reach your objectives.

Define

Toptal leaders collaborate with your team to define your specific goals and service needs, evaluating multiple approaches and aligning requirements with your strategic objectives to define the best solution.

Develop

Once your service is defined and you have your talent or team on board, they will create your unique project timeline, process, and initial proposals, whether you’re expanding your current testing capabilities or overhauling your testing infrastructure.

Deploy

Toptal will get to work, tracking quality assurance, handling project management, and maintaining the delivery schedule.

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Robert Orshaw

CEO, Technology Services

As Toptal’s CEO of Technology Services, Robert leads strategy and operations across our technical services portfolio, spanning AI, automation, and operations. He previously served as Deloitte’s Managing Director & Chief Commercial Officer, transforming its Cloud Operate and Engineering business into a multibillion-dollar operation. He held senior roles at IBM, Velocity, co-founded Corio, and was CIO for two Fortune 500 companies.As Toptal’s CEO of Technology Services, Robert leads strategy and operations across our technical services portfolio, spanning AI, automation, and operations. He previously served as Deloitte’s Managing Director & Chief Commercial Officer, transforming its Cloud Operate and Engineering business into a multibillion-dollar operation. He held senior roles at IBM, Velocity, co-founded Corio, and was CIO for two Fortune 500 companies.

Previously At

Functional Testing Services That Deliver Value

Toptal delivers leading functional testing services through its diverse talent network and flexible delivery models. We implement the right skills at each project phase, blending expertise from various roles for seamless execution.

End-to-End Delivery by Toptal
On-demand Talent and Teams

End-to-End Delivery by Toptal

Comprehensive project delivery, tailored to your specific requirements.

CEO, Technology Services

Delivery Manager

Functional Testing Lead

Test Automation Engineer

Functional Testing Expert

Manual and Functional Testing

Test Automation Engineer

Functional QA Consultant

Robert Orshaw

CEO, Technology Services

Previously at

Technology Experience

35+ Years

Rachael Karaffa

Delivery Manager

Rachael serves as a Delivery Manager at Toptal with a focus on leading diverse global teams in developing innovative solutions for our clients. She works across multiple disciplines, including technology, marketing, and management consulting. Rachael specializes in managing people and client relationships, process optimization, and driving teams toward optimal business outcomes.

Previously Managed Client

Experience

9+ Years

Sargis Sargsyan

Verified Expert in Engineering

14+ Years

of Experience

Functional Testing Lead

Sargis is a QA engineer and currently a director of quality engineering with 14+ years of experience and deep expertise in test automation. He has worked with companies specializing in mobile, web, SaaS, and enterprise applications. Sargis has been an excellent asset to distributed international teams, he is an advocate for the Agile methodology, and a skilled practitioner of Agile, Scrum, and Kanban.

Previously at

Sebastian Ostrowski

Verified Expert in Engineering

18+ Years

of Experience

Test Automation Engineer

Since 2006, Sebastian's been working in the field of software quality assurance, specializing in tests (automation and strategy definition). He's developed appropriate processes, prepared documentation, selected automation approaches, and implemented test automation frameworks, tests, and CI/CD integrations. In addition, he's built various automation solutions—from complicated event-driven distributed systems with microservices to web apps.

Previously at

Chieko Higashi

Verified Expert in Engineering

20+ Years

of Experience

Functional Testing Expert

Chieko is a senior QA engineer with more than 20 years of experience testing software in various industries such as apparel, fintech, and security. She’s led teams in the implementation of software QA, test automation, and manual QA, as well as managing QA test plans to ensure that the end product is robust and high-quality. Chieko is passionate about achieving quality by following good development and QA processes, and is wholeheartedly dedicated to ensuring that software meets customers’ needs.

Previously at

Milorad Popovic

Verified Expert in Engineering

15+ Years

of Experience

Manual and Functional Testing

Milorad has more than 15 years of experience in IT projects involving Microsoft, Cisco, virtual systems, networking, VoIP, and other technologies. He is a highly self-motivated and professional QA leader who consistently seeks to improve work processes. A strong team player, he provides support and guidance to colleagues and thrives in a variety of work environments.

Previously at

Dolly Arora

Verified Expert in Engineering

11+ Years

of Experience

Test Automation Engineer

Dolly is a QA engineer with more than 11 years of experience in a range of industries, including real estate, travel, finance, and aviation. She has created multiple testing frameworks from the ground up using Selenium, TestNG, Cucumber, and Cypress and has automated QA processes. Dolly manages test execution not only from the technical point of view but also from the customer’s, as she believes product usability is as vital as functionality.

Previously at

Dimitrios Karavias

Verified Expert in Engineering

12+ Years

of Experience

Functional QA Consultant

Dimitris is a QA automation architect focused on de-risking clients’ technical investments by upskilling teams and automating processes. He particularly enjoyed his four years at Novoda, the mobile agency, where he worked on challenging projects with no existing testing practices. Dimitris has set up clients’ QA teams from scratch and developed his leadership skills.

Previously at

On-demand Talent and Teams

30,000+ vetted professionals, ready to deploy individually or in teams.

Functional QA Expert

Quality Assurance Expert

Functional Testing Expert

Test Automation Engineer

Manual QA Engineer

Cross-Platform QA Expert

Security Expert

Quality Assurance Expert

Agile Project Manager

Verified Expert in Engineering

18+ Years

of Experience

Functional QA Expert

Christina is a senior QA engineer with expertise in test automation, test management, and manual testing for web and mobile applications. She has created test automation frameworks from the ground up using Selenium WebDriver in several projects as well as automating API testing using REST Assured and Postman. With experience in both private and public sectors, Christina has worked with large, medium-size, and small startup companies.

Previously at

Verified Expert in Engineering

9+ Years

of Experience

Quality Assurance Expert

Jakub has been a QA leader and engineer since 2015. He is focused, committed, and driven by results. As an analytical thinker with a data-driven approach to decision making, he's also a perfectionist who knows the meaning of "good enough." His business acumen and sense of responsibility enable him to decide whether to apply a flexible approach or stand his ground to deliver the best solution. Jakub keeps an open mind and never disregards suggestions without giving them some thought.

Previously at

Verified Expert in Engineering

11+ Years

of Experience

Functional Testing Expert

Satish is an adaptable and technically strong professional with a customer business value-added mindset and several years of experience in quality assurance for companies like Deloitte and Consensys. While Satish specializes in Selenium, Cypress, and API testing, he's also comfortable building automation test frameworks and recently led the technical portfolio for an automation project.

Previously at

Verified Expert in Engineering

13+ Years

of Experience

Test Automation Engineer

Ravi is a QA test automation engineer with 13+ years of web and mobile experience. He delivers solutions at different levels of the test pyramid and helps clients introduce CI/CD workflows, create deployment pipelines, and improve overall QA processes and outcomes. Ravi's enterprise QA experience includes LTI, ClinicalWorks, CitiusTech, Tata Consultancy Services, and Capgemini. In addition to three ISTQB certifications, Ravi is a Certified Scrum Master.

Previously at

Verified Expert in Engineering

6+ Years

of Experience

Manual QA Engineer

Alejandro is a QA engineer with over six years of experience in manual and automated testing for web and mobile applications within the banking and fintech sectors. He has experience designing, building, executing, and maintaining automated tests, including API testing and integration with the CI/CD methodology. Alejandro is self-sufficient and has taught himself various stacks, making him efficient in implementing technologies, tools, or techniques needed for the team or the client.

Previously at

Verified Expert in Engineering

11+ Years

of Experience

Cross-Platform QA Expert

Natalya is a QA engineer experienced in testing web, hybrid, native mobile, and desktop applications. She has worked in various business domains, including fintech, finance, medicine, and telecommunications, testing front-end and back-end parts and different console applications.

Previously at

Verified Expert in Engineering

22+ Years

of Experience

Security Expert

Subbu is a subject matter expert in information security and has more than 22 years of information technology experience. He has assisted large enterprise customers in the banking, telecommunication, and e-commerce sectors with security transformation, DevSecOps, security architecture, and implementations. Subbu’s security expertise includes AWS, GCP, IAM, enterprise security, data protection, and application security and compliance.

Previously at

Verified Expert in Engineering

20+ Years

of Experience

Quality Assurance Expert

Seema brings more than 20 years of software testing and quality assurance expertise to the table. She has substantial experience with manual testing and the test automation of web and mobile applications. Seema is a certified Scrum master, an IBM-certified Db2 professional, and an AWS-certified solutions architect comfortable with Agile and Waterfall approaches. Her in-depth knowledge of API and performance testing delivers excellent results.

Previously at

Verified Expert in Project Management

6+ Years

of Experience

Agile Project Manager

Kamil is an Agile project manager and Scrum master with a robust business analysis and change management background. He has extensive experience leading teams and implementing Agile scaling practices at international companies, including BAE Systems, an FTSE100 company and the largest defense contractor in Europe. Kamil is a certified Lean Six Sigma Black Belt, PMP, and PMI-ACP.

Previously at

Looking for guidance about the perfect functional testing service for your needs?

Get a Free Consultation Now

Looking for guidance about the perfect functional testing service for your needs?

UNRIVALED EXPERTISE

Our Talent Has Worked With Top Companies

Having previously worked with these leading global companies, our talent brings valuable insights and expertise to deliver world-class outcomes.

WHY ORGANIZATIONS CHOOSE US

Toptal in Action

Discover the cutting-edge benefits our clients enjoy from the global Toptal network.

Toptal enhances QA processes for leading social media platform.

Challenge: The platform’s QA framework lacked sufficient test coverage, making it difficult to manage concurrent regression tests across mobile platforms and verify ticket tasks effectively.

Solution: Toptal introduced a structured testing approach that enabled same-day regression testing for iOS and Android, along with efficient ticket verification. TestRail was implemented for test case management and Jira for task documentation, improving clarity and collaboration through regular meetings with management.

Outcome: The structured approach increased test coverage, helping identify and resolve critical bugs before major releases. Enhanced QA processes improved operational efficiency, boosted confidence in releases, raised user satisfaction, and reduced downtime.

Toptal Ranked #1 Most Reliable Professional Services Company in America

Newsweek and Statista’s rankings were based on an independent survey of more than 2,400 decision-makers at Fortune 500s.

IBM — Newsweek's Most Reliable Companies in America 2026 ranking. Toptal is ranked #11, the highest-ranked professional services firm.

See the Most Reliable Companies in America

Methodology for the Rankings

How likely the respondent is to recommend the selected company to others.

Measures the convenience of interaction with the company and efficiency of processes.

Measures the company’s cost-effectiveness and quality relative to price.

Measures whether the company consistently meets or exceeds expectations in quality and timeliness of deliverables.

Measures the company’s ability to consistently fulfill commitments and maintain customer trust.

See the Most Reliable Companies in America

OUR THOUGHT LEADERSHIP

Explore Insights From the Functional Testing Field

Read the latest articles and resources to keep you current on emerging trends in functional testing strategy and test automation.

8 Automated Testing Best Practices for a Positive Testing Experience

Testing doesn’t have to be tedious. With these automated testing best practices and tips, software engineers can leverage automated tests to boost their productivity and make their work more enjoyable.

Lev Yastrebov

Verified Expert in Engineering

16 Years of Experience

Lev is an accomplished C# and .NET developer who leverages test-driven development, static analysis, and in-depth knowledge of technologies to solve tasks with robust, clean code. At leading smart marine technology company Wärtsilä, he created an algorithm for 3D seafloor mapping that resolves conflicting data from thousands of nautical charts.

Expertise

Test Automation .NET

Previously at