QA Engineer (m/f/d)

RTB House

Location: Poland We are:  RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Our proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to achieve outstanding results and meet their goals at every stage of the funnel. Join RTB House and lead our AI Engineering Lab, a team dedicated to pioneering innovation and boosting engineering productivity by leveraging the latest advancements in Agentic AI. We are looking for a hands-on technical leader with a strong, traditional software engineering background. In this role, you won't just be writing custom code from scratch. Our approach is highly pragmatic: we build internal tools, intelligent agents, and MCPs to supercharge our engineering workflows. A critical part of our philosophy is knowing when to leverage off-the-shelf products and existing frameworks versus when to architect and build custom solutions. We need a leader who can navigate this landscape and pick the absolute best solution for the task at hand. You will: * Lead & Mentor: Guide a small team of software engineers, fostering a culture of technical excellence, collaboration, and continuous improvement. Set and maintain high standards for code quality and system performance. * Drive Pragmatic Architecture: Design and develop distributed systems, internal productivity tools, and multi-agent architectures. You will own the "build vs. buy/integrate" decisions - choosing the right mix of off-the-shelf AI products, APIs, and custom-built components. * Innovate with Agentic AI: Spearhead the evaluation, prototyping, and integration of novel Agentic AI systems, LLMs, and Model Context Protocols (MCPs) to solve complex business and engineering problems. * Own the Execution: Manage the full development lifecycle from concept to production deployment. Ensure that the solutions we deploy are reliable, scalable, maintainable, and deliver real value. * Collaborate Cross-Functionally: Work closely with Product Manager, Engineering Managers, and broader engineering teams to align the Lab’s innovations with company strategy and platform requirements. Desired experience: * Strong Software Engineering Background: Minimum of 6 years of professional experience building, deploying, and operating complex, large-scale distributed systems (e.g., microservices, event-driven architectures). * Technical Leadership: Demonstrated experience defining technical roadmaps, mentoring engineers, leading code reviews, and driving high-level architectural decisions. * Programming Languages: High proficiency in Python is mandatory. Experience with at least one other language (such as Java, Go, TypeScript, or Scala) is highly preferred. * Solution Evaluation: Strong intuition and experience in evaluating third-party tools, frameworks, and vendor solutions to solve engineering problems efficiently rather than always building from scratch. * AI/ML Integration: Experience integrating large language models (LLMs) into production applications, alongside a basic understanding of the Machine Learning lifecycle and MLOps practices. Nice to have: * Direct experience building internal developer tools, custom Model Context Protocols (MCPs), or using Agentic AI frameworks (e.g., Vercel AI SDK, LangChain, AutoGen, Agent Development Kit). * Experience with cloud platforms (AWS, GCP, Azure) and containerization technologies (Docker, Kubernetes). * Familiarity with the ad-tech industry and real-time bidding (RTB) systems. We Offer: * Projects focused on extreme performance and high code quality – clean code and solid code reviews are our standard. * Collaboration within an interdisciplinary, self-sufficient team (including DevOps, database experts, backend developers, product designers, and QA engineers). * Access to modern technologies and the opportunity to apply them in large-scale, high-impact projects. * Cooperation based on B2B contract. * You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow. Apply now! You don't need to tick every box to apply. If you are passionate about software engineering, send us your CV, and we'll review it.

RTB House

We are:  RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Our proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to achieve outstanding results and meet their goals at every stage of the funnel. Join RTB House and lead our AI Engineering Lab, a team dedicated to pioneering innovation and boosting engineering productivity by leveraging the latest advancements in Agentic AI. We are looking for a hands-on technical leader with a strong, traditional software engineering background. In this role, you won't just be writing custom code from scratch. You will be an architect of efficiency. Our approach is highly pragmatic: we build internal tools and autonomous agents to supercharge our engineering workflows. You will be expected to navigate the "build vs. buy/integrate" landscape, determining when to leverage off-the-shelf LLM products and when to architect a custom, high-performance solution. You will: * Drive Technical Excellence: Act as a technical pillar within the Lab, implementing high-standard code and sophisticated system designs. You will mentor mid-level peers and lead deep-dive code reviews. * Architect Multi-Agent Systems: Design and deploy distributed systems and multi-agent architectures that automate complex engineering tasks. You will own the architectural decisions for "build vs. integrate" strategies. * Innovate with Agentic AI: Spearhead the evaluation and prototyping of LLMs, Agentic frameworks, and Model Context Protocols (MCPs). You will transform theoretical AI advancements into production-ready tools. * Own the Full Lifecycle: Take responsibility for the entire development cycle. From initial concept and API integration to production deployment and long-term scalability. * Influence Product Strategy: Partner with Product and Engineering Managers to ensure the Lab’s innovations align with the broader company roadmap and provide measurable ROI to our developers. Desired experience: * Pragmatic Architect: Proven ability to evaluate third-party tools and vendor solutions against custom-built software to find the most efficient path forward. * Technical Stack: High proficiency in Python is mandatory. Significant experience with at least one other language (Java, Go, TypeScript, or Scala) is highly preferred. * AI/ML Implementation: Hands-on experience integrating LLMs into production environments. * Systems Thinker: Ability to define technical roadmaps for specific features and drive high-level design choices that prioritize maintainability and performance. * C1 level in English and Polish. Nice to have: * Direct experience building internal developer tools, custom Model Context Protocols (MCPs), or using Agentic AI frameworks (e.g., Vercel AI SDK, LangChain, AutoGen, Agent Development Kit). * Experience with cloud platforms (AWS, GCP, Azure) and containerization technologies (Docker, Kubernetes). * Familiarity with the ad-tech industry and real-time bidding (RTB) systems. We offer: * Projects focused on extreme performance and high code quality – clean code and solid code reviews are our standard. * Collaboration within an interdisciplinary, self-sufficient team (including DevOps, database experts, backend developers, product designers, and QA engineers). * Access to modern technologies and the opportunity to apply them in large-scale, high-impact projects. * Cooperation based on B2B contract. * You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow.

RTB House

Location: Poland (Remote/Flexible) We are:  RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Its proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to generate outstanding results and reach their goals at every stage of the funnel.  We are looking for engineers to join our Bidding Platform organization which is the core of the RTB business, processing over 20 million requests per second to participate in real-time auctions and display advertisements to customers from 90+ countries. If you want to work on technically complex and demanding solutions, this is the opportunity for you! Our Staff Engineers are experts who combine deep technical expertise with a strong sense of ownership, and they take on Tech Lead roles in complex, cross-team projects. You will: * Gain deep understanding of our ad technology and become familiar with ad industry standards: OpenRTB, MRAID, VAST etc. * Analyse issues with our end-to-end ad workflows, reproduce problematic cases, and come up with proposals for improvements. * Design technical and operational solutions that improve ad experience and our performance metrics. * Lead implementation of the aforementioned architectural solutions, ensuring its high quality, and evaluating its impact on business performance. * Provide hands-on technical leadership: solving complex system challenges, participating in planning and scoping of projects, and ensuring the implementation of the highest coding standards through participation in code reviews. * Cooperate with stakeholders across the entire organization. Desired experience: * 10+ years of hands-on experience in designing, developing and deploying complex software systems. * 3+ years of tech leadership experience (e.g. tech lead, staff, architect roles) in medium or large organizations. * Excellent understanding of complex, distributed IT systems - from the hardware and networking level, through software, to algorithms. * C1 level in English and Polish. Nice to have: * Experience in the AdTech/Real Time Bidding space. Selected technologies used:  * Java, Python * Aerospike, Memcached * Google Cloud Platform, BigQuery, MinIO * Kafka, Clickhouse * PostgreSQL * Elasticsearch * Kubernetes, Prometheus * Jenkins, Graphite We Offer: * Projects focused on extreme performance and high code quality – clean code and solid code reviews are our standard. * Collaboration within an interdisciplinary, self-sufficient team (including DevOps, database experts, backend developers, product designers, and QA engineers). * Access to modern technologies and the opportunity to apply them in large-scale, high-impact projects. * Cooperation based on B2B contract. * You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow. You don't need to tick every box to apply. If you are passionate about software engineering, send us your CV, and we'll review it.