Senior Full-Stack Engineer - Team Optimize

About the roleTaktile is a high-growth, post product-market-fit start-up on a fast trajectory to becoming a market leader in automated decisioning. As our customers run an increasing share of their critical decisions on Taktile, improving those decisions using production data becomes a core part of the product. Team Optimize builds the capabilities that allow customers to evaluate and improve decision flows using historical data — across fraud, AML, onboarding, KYC/KYB, underwriting and credit use cases.As a Senior Full-Stack Engineer, you will own backend systems and APIs that operate on large volumes of decision data and expose them through customer-facing product surfaces. Your work directly influences outcomes such as reducing false positives, improving approval rates, and increasing confidence when shipping changes to production.At scale, the systems you build will:Process millions of decisions per dayPersist and query terabytes of data per dayExecute large-scale experiments over billions of historical decisionsServe low-latency APIs on top of append-heavy datasetsWhat You'll DoBuild and own backend components written in Python / FastAPI, running on an AWS serverless architecture, powering customer-facing capabilities for evaluating and improving decision flows.Design, extend, and maintain complex backend subsystems that operate on large volumes of historical decision data and expose them through well-structured APIs.Review pull requests with depth, contribute to architectural decisions, and help maintain a high bar for code quality, reliability, and delivery velocity, including CI/CD improvements where needed.Collaborate closely with Product, Solutions, and other engineering teams to translate business problems into scalable technical solutions.Actively participate in team rituals such as planning sessions, demos, and technical deep dives, shaping both execution and long-term direction.Grow as an engineer by working on a foundational part of the product, learning from experienced peers, and taking increasing ownership over systems and outcomes.Requirements7+ years of backend engineering experience with ownership of APIs and production systems.Experience building customer-facing platforms.Comfort working with large datasets where scale, performance, and correctness matter.Prior industry experience with Python. Java is a plus.Experience with AWS services and serverless architectures.Fluency in English, both written and spoken, is crucial to lead communication in our globally distributed environment.Excited about the potential of AI-driven automation and actively using AI tools to improve productivity and engineering workflows.Location: Berlin (hybrid setup). Taktile will not cover relocation services for this role.Ideal, But Not RequiredExperience with large-scale data technologies such as Apache Iceberg, Athena, Spark, or similar.Experience with React and TypeScript.Experience building experimentation or evaluation systems.Exposure to fraud, AML, risk, or financial decisioning domains.What we offerWork with colleagues that lift you up, challenge you, celebrate you and help you grow. We come from many different backgrounds, but what we have in common is the desire to operate at the very top of our fields. If you are similarly capable, caring, and driven, you'll find yourself at home here.Experience a truly flat hierarchy and communicate directly with founding team members. Having an opinion and voicing your ideas is not only welcome but encouraged, especially when they challenge the status quo.Learn from experienced mentors and achieve tremendous personal and professional growth. Get to know and leverage our network of leading tech investors and advisors around the globe.Receive a top-of-market equity and cash compensation package.Get access to a self-development budget you can use to e.g. attend conferences, buy books or take classes.Receive a new Apple MacBook Pro, as well as meaningful home office set-up.Our StanceWe're ... (truncated, view full listing at source)