20 Best A/B Testing Companies in Europe (2026)

Gilzor develops web and mobile products while incorporating experimentation into product design and improvement cycles. Its work covers idea validation, business analysis, UI/UX design, quality assurance, web development, mobile development, and ongoing product support. A/B testing can be applied to interfaces and features as teams collect feedback and evaluate different approaches before committing to broader changes.

Product work can continue from early validation through development and post-launch iterations. Gilzor also works with existing products that need new functionality, interface changes, process automation, or technical modernization, giving teams a development partner capable of implementing the variants and improvements identified through experimentation.

OSKI Solutions develops conversion-focused web experiences with analytics and experimentation built into the technical foundation. Its landing-page development service includes independently swappable sections, event tracking, analytics, and experiment hooks that make it possible to test headlines, layouts, calls to action, and other page components without rebuilding the entire page.

The company also handles frontend and backend development, cloud infrastructure, UI/UX design, QA, integrations, and ongoing software improvements. Its development stack supports projects where experimentation needs to connect with CRM systems, marketing automation, APIs, headless CMS environments, or existing business software rather than operate as a standalone marketing activity.

Fresh Egg provides dedicated A/B testing and CRO services supported by strategists, analysts, developers, and user-experience specialists. Its experimentation teams can take a backlog of ideas, structure them into a testing roadmap, build the experiments, and validate the technical setup before results are used for decision-making.

Its wider conversion services include research, customer journey analysis, analytics, experimentation maturity reviews, and optimization strategy. A/B testing development is handled in-house, which is useful for teams that have hypotheses but lack the development resources required to put variations into production reliably.

Conversion is an experimentation-focused agency whose services combine A/B testing, UX research, personalization, analytics, and conversion-centered design. Its teams develop experimentation roadmaps, create hypotheses, design and build tests, monitor experiments, and analyze results rather than treating testing as an isolated technical task.

The agency also works on product and pricing experimentation, allowing organizations to validate changes beyond standard website layouts. Its methodology incorporates qualitative research alongside controlled experiments, with testing applied to messaging, functionality, user journeys, offers, and commercial models.

Lengreo combines digital marketing, web development, UX work, and conversion optimization. Its CRO approach focuses on understanding what visitors do after reaching a website, identifying friction in conversion journeys, and improving the pages and experiences responsible for leads or sales.

Its broader capabilities cover website development, paid advertising, SEO, marketing strategy, analytics, and lead generation. This combination allows testing insights to be carried into landing pages and other digital touchpoints instead of remaining limited to reporting. Lengreo also publishes conversion-focused work and case studies involving improvements to website performance and lead-generation funnels.

Creative CX is a specialist experimentation and UX consultancy working across research, optimization, personalization, and product experimentation. Its full-service experimentation work combines strategy, UX, development, QA, and analysis, giving clients access to both the research and technical resources needed to run tests.

Its developers build client-side and server-side A/B experiments, while UX specialists work on prototypes, customer journeys, behavioral analysis, and usability testing. Creative CX also helps companies assess existing experimentation programs, implement testing technology, and create operating structures for scaling experimentation across multiple teams.

Speero works on growth experimentation using customer research, data science, engineering, CRO, and A/B testing. Its model is designed for organizations that need experimentation to become a repeatable operating process rather than a collection of unrelated tests managed by separate teams.

The company also advises on experimentation technology and implementation. This includes evaluating testing platforms, setting up and validating tools, checking metrics against backend data, documenting configurations, and establishing measurement processes. Its work can extend across websites, applications, marketing, products, sales flows, and email.

Itexus provides UI/UX design and software development services that include A/B testing, usability analysis, prototyping, and product analytics. Its design process can compare alternative visual concepts, layouts, and user flows before changes are incorporated into a broader application or website.

The company also develops web and mobile applications alongside its product design and consulting work. Its UI/UX services combine prototyping, usability audits, usage analytics, and A/B testing, allowing design alternatives and user flows to be evaluated as part of broader product development and redesign work.

Webtrends Optimize provides a full-stack experimentation and personalization platform. Its A/B testing capabilities cover websites and landing pages as well as server-side and application experiments, allowing teams to choose between visual editing and more technical implementations depending on the scope of the change.

The platform also includes multivariate testing, personalization, social proof, product recommendations, and audience targeting. Businesses can use the software directly or combine it with optimization services and agency support, making the offering suitable for both internal experimentation teams and organizations that need external guidance.

AB Tasty develops an experimentation platform covering web experimentation, feature experimentation, personalization, and digital experience optimization. Marketing and product teams can use it to create A/B tests, multivariate experiments, and split tests while tracking goals and evaluating how different experiences affect user behavior.

The platform also supports server-side experimentation and feature management through SDK- and API-based implementations. Feature flags, progressive rollouts, targeting rules, and controlled experiments allow development teams to test product functionality alongside the website experiments typically managed by marketing and CRO teams.

Net Devs develops enterprise software and modern frontend applications across React, Angular, Vue, TypeScript, .NET, JVM, Node.js, Python, and Go. Its delivery model includes discovery, requirements analysis, prototyping, architecture planning, development, and frontend testing, with automated and manual QA incorporated before production deployment.

The company also works on existing systems that require modernization or continuous product development. Teams can handle interface changes, new functionality, cloud infrastructure, integrations, and ongoing releases, while prototypes and technical decisions are tested with stakeholders before implementation.

Kameleoon provides experimentation and personalization technology for digital product and marketing teams. Its platform supports A/B testing and the continuous optimization of customer journeys, with experimentation used to evaluate changes to content, interfaces, conversion funnels, and digital product experiences.

Personalization tools operate alongside experimentation, allowing teams to target user groups and validate whether customized experiences actually improve outcomes. Kameleoon has also been expanding prompt-based and AI-assisted experimentation capabilities while maintaining testing and personalization as core parts of its product.

Omniconvert develops ecommerce optimization technology built around experimentation and customer intelligence. Its Explore product provides A/B and multivariate testing, a no-code experiment builder, personalization, and segmentation for teams working on storefronts and conversion journeys.

The wider platform connects experimentation with surveys, customer feedback, and behavioral data. This gives ecommerce teams the option to combine quantitative test results with information about customer sentiment and audience segments when prioritizing future optimization work.

Mobian is a software development studio working on mobile applications, digital products, backend systems, APIs, cloud infrastructure, and QA. Its product development process can cover the complete path from wireframes and architecture through implementation, production deployment, monitoring, and post-launch improvements.

Product analytics is another part of its development offering, with technologies such as Google Analytics, Crashlytics, and New Relic referenced in its mobile development work. Mobian also develops MVPs with user-behavior monitoring and supports established applications through performance monitoring, scaling, feature development, and continued technical maintenance.

Convertize provides conversion rate optimization services built around analytics, behavioral insights, consumer psychology, and testing. For websites with sufficient traffic, its team develops hypotheses and runs A/B tests on selected pages while analyzing how changes affect conversion performance.

Its CRO services can also include UX audits, value-proposition work, pricing optimization, landing-page optimization, user-behavior analysis, funnel analysis, and on-site surveys. Design and optimization work can therefore be based on both observed behavior and controlled experiments rather than relying only on general UX conventions.

konversionsKRAFT specializes in conversion optimization, customer experience, experimentation, and customer-centric digital growth. Continuous A/B testing is integrated with user research and optimization strategy to determine which changes improve digital journeys and commercial outcomes.

Its experimentation work also addresses the organizational side of testing. The company helps teams develop repeatable experimentation processes, choose meaningful KPIs, connect testing with broader business data, and create internal structures where product decisions can be validated systematically rather than through isolated optimization campaigns.

DEPT® delivers CRO and experimentation as part of a wider combination of technology, data, design, and digital marketing services. Its optimization teams work with analytics and user-behavior data to identify friction, create test backlogs, design experiments, implement variants, and evaluate the results.

The agency also supports experimentation through platforms such as Optimizely, including A/B tests, multivariate testing, personalization, and ongoing optimization programs. Designers, developers, data specialists, and CRO consultants can work together on the same program, which is useful when experiments require more substantial product or interface changes.

Credo is a specialist CRO agency providing conversion audits, ongoing optimization, user research, design, development, and A/B testing. Its process combines behavioral data, analytics, user psychology, and structured hypotheses to determine which changes should be implemented or tested.

Full-service engagements can move from site analysis into a collaborative optimization roadmap and then into design, development, and testing. The agency works with testing software already installed by the client or can recommend an appropriate platform when experimentation needs to be introduced from scratch.

SoftPro develops custom software and web applications using technologies that include React, Node.js, ASP.NET, .NET Core, Azure, and AWS. Its services cover frontend and backend engineering, custom web applications, cloud development, integrations, and software designed around specific operational or customer-facing requirements.

The company works across the development lifecycle from design and implementation through deployment and post-launch planning. Its portfolio includes CRM platforms, SaaS data-integration products, business portals, support systems, and social-commerce solutions, giving its team experience with applications where interfaces, workflows, and customer interactions can continue to evolve after release.

fifty-five combines data consultancy, marketing technology, customer experience, and experimentation. Its work can involve controlled tests for digital campaigns and conversion journeys, using data analysis to determine whether changes produce incremental improvements rather than relying solely on platform attribution.

The company also supports broader customer-experience and CRO initiatives involving analytics, tracking, technology, media, and data science. This makes experimentation part of a wider measurement framework, particularly for organizations that need to connect test results with marketing performance or customer data across several markets.