Ninetailed

Niche leader in composable/headless personalization, acquired by Contentful to power its native personalization offering

Ninetailed was a Berlin-based personalization and A/B testing platform purpose-built for composable and headless architectures. Founded in 2021, the company addressed a critical gap in the modern web stack: as brands increasingly adopted headless CMS and composable commerce architectures, traditional personalization tools struggled to integrate cleanly. Ninetailed offered a developer-friendly SDK and API-first approach that allowed teams to deliver personalized experiences directly within their content layer, without requiring heavy engineering lift or separate data pipelines. The platform was deeply integrated with leading headless CMS platforms, most notably Contentful, enabling marketers and developers to define audience segments, run experiments, and deliver tailored content variations from within familiar editorial interfaces. Its tight coupling with the composable stack made it a natural fit for enterprise digital teams seeking to unify content and personalization workflows. Ninetailed positioned itself as the personalization layer for the composable web, competing with both legacy personalization vendors and newer entrants in the experimentation space. In 2023, Contentful acquired Ninetailed, recognizing the strategic value of embedding personalization natively into its content platform. Following the acquisition, Ninetailed's technology was integrated into Contentful's product suite, effectively ending Ninetailed's existence as a standalone brand. The acquisition underscored the growing importance of personalization as a first-class feature within content management platforms, and Ninetailed's team and technology became the foundation for Contentful's personalization capabilities.