Software Engineer (Python) at Lynxtech | Madrid

Note: Only candidates located in Spain will be considered. Visa sponsorship is not available. Lynx Financial Crime Tech S.A develops AI-driven systems to detect and predict behavioral patterns in financial transactions. The team draws on backgrounds in both finance and academia, focusing on self-learning tools that support low-latency processing for clients …

Veeam, the world leader in data resilience, empowers businesses to access and control their data anytime and anywhere. Our comprehensive suite includes data backup, recovery, portability, security, and intelligence. Headquartered in Seattle, Veeam safeguards over 550,000 customers globally, ensuring their operations remain uninterrupted. Join our journey as we innovate, grow, and make significant contributions for some of the largest brands globally. The future of data resilience is bright—take bold steps with us.About the Role: With the recent acquisition of Securiti AI, a frontrunner in AI-driven data security posture management (DSPM), Veeam is on the lookout for a Senior Sales Engineer. In this pivotal role, you will provide technical leadership within our sales team, focusing on the Securiti AI portfolio. Collaborating with a Securiti Sales Specialist, you will support 3-5 Account Executives and Veeam Solution Engineers, acting as the technical authority.Your key responsibilities will involve guiding customers from initial needs assessment to tailored solution design, showcasing the value through hands-on demonstrations and proofs of concept. Success in this position hinges on your strong technical acumen and your ability to foster trust with clients.What You’ll Do: Serve as the primary technical resource for Securiti AI solutions throughout the sales process.Lead in-depth technical discussions and tailor security solutions to meet customer needs.Address client requirements in data discovery, posture management, and compliance.Design and deliver engaging product demonstrations and proofs of concept.Work alongside product, engineering, and customer success teams to ensure seamless transitions.What You’ll Bring: Extensive experience in pre-sales or sales engineering roles.Deep knowledge of data and cloud security.Exceptional communication skills for engaging both technical and business stakeholders.Over 10 years of technical sales experience in the security domain.More than 15 years in Software/SaaS/Enterprise technical sales.Practical experience with AWS, Azure, or GCP.Familiarity with data privacy/security standards such as GDPR, NIST 800-53, and ISO 27001.

We invite you to submit your CV in English, along with your English proficiency level.Mindrift connects talented specialists with project-based opportunities in AI for leading tech companies, focusing on the testing, evaluation, and enhancement of AI systems. This is a project-based engagement, not a permanent position.About the RoleWe are looking for a seasoned Python developer with extensive experience in functional testing. You should possess strong skills in Linux and Docker, as well as the ability to read and understand code in multiple languages with the help of LLMs (e.g., C, Rust, Go). You will translate requirements for migration tasks and confidently utilize tools like Roo Code or Claude Code to expedite iterative development.Key ResponsibilitiesDevelop functional black box tests for large codebases across various source languagesEstablish and manage Docker environments to ensure 100% reproducible builds and testing across different platformsMonitor code coverage and set up automated scoring criteria to adhere to industry benchmark standardsUtilize LLMs (Roo Code, Claude) to streamline development cycles, automate repetitive tasks, and enhance overall code qualityRequirementsMinimum of 5 years of experience as a Software Engineer, primarily focused on PythonExtensive experience with pytest (including fixtures, session-scoped, timeouts) and crafting black-box functional tests for CLI toolsExpert-level proficiency in Docker (creating reproducible Dockerfiles, managing user contexts, ensuring secure workspaces)Strong Linux & Bash scripting skills and ability to debug within containersFamiliarity with modern Python tooling (uv, pyproject.toml, packaging)Capability to read and comprehend multiple coding languages with LLM assistance (e.g., C, C++, Rust, Go)Experience with LLMs (Claude Code, Roo Code, Cursor) to enhance iterative development and generate test casesEnglish language proficiency at B2 level or higherPreferred QualificationsPrevious experience with agent evaluation platforms and MCP CLITechnologies and Tools: Python (pytest, uv, Pillow), Docker, Bash, Git Submodules, C/C++/Rust/Go (reading), Dagger, GitHub Codespaces, LLMs (Claude Code, Roo Code, Cursor), coverage.py, gcov, kcov.BenefitsWhat We Offer:Project-based freelance collaboration through the Mindrift platform (powered by Toloka AI)Completely remote and flexible contribution—choose when and how much you want to work (20-30 hours per week)Compensation varies by project scope and required expertise, with AI trainers earning up to $30 per hour.

Location: Madrid Office About Aircall Aircall builds an AI-driven customer communications platform used by over 22,000 businesses worldwide. Our product brings together voice, SMS, WhatsApp, and AI features in a single workspace, helping teams boost revenue, resolve issues faster, and scale their operations efficiently. Headquartered in Paris, Aircall has a strong global footprint with offices in Seattle, Madrid, London, Berlin, San Francisco, New York City, Sydney, and Mexico City. Our company is growing quickly, supported by leading investors and advances in AI across our product lines. Our Culture We focus on customer satisfaction, data-driven decisions, and meaningful results. Team members are encouraged to take ownership, keep learning, and act quickly but thoughtfully. Collaboration, trust, and impact shape our daily work. About the New Product Unit Aircall is launching a New Product Unit dedicated to advancing autonomous sales. The team is building an AI Orchestration Layer that records and understands customer interactions across calls, video, email, and WhatsApp. This system will automate sales workflows such as CRM updates, follow-ups, task creation, and coaching insights. Our long-term vision is a self-optimizing Sales OS powered by specialized AI agents working together to improve revenue processes. Role Overview: Senior Backend Software Engineer (Python) This position calls for an experienced backend engineer with strong Python skills, ready to work beyond traditional backend boundaries. The role suits someone who values both clean architecture and practical progress, and who can balance high-quality work with the need for speed in a startup setting. What You Will Do Tackle complex technical challenges, including distributed systems, AI orchestration, architecture, performance, and scalability Contribute to the design and implementation of backend systems for the AI Orchestration Layer Work closely with product and engineering teams to deliver new features Iterate quickly, shipping solutions and learning from feedback Who Will Thrive Engineers who enjoy solving difficult problems and making architectural decisions Those who can dive deep into technical details while keeping an eye on rapid delivery People who take pride in their work and appreciate the pace of a growing company

Veeva Systems is a purpose-driven organization and a leader in the industry cloud sector, empowering life sciences companies to expedite the delivery of therapies to patients. As one of the fastest-growing SaaS companies in history, we achieved over $2 billion in revenue in our last fiscal year and continue to see vast growth potential.Our core values at Veeva are: Do the Right Thing, Customer Success, Employee Success, and Speed. We are not just any public company; in 2021, we made history by becoming a public benefit corporation (PBC), which legally commits us to balancing the interests of customers, employees, society, and investors.As a Work Anywhere company, we offer flexibility for you to work from home or in the office, allowing you to thrive in your preferred environment.Join us in transforming the life sciences industry, as we commit to making a positive impact on our customers, employees, and communities.The RoleOpenData Clinical serves as the cornerstone for intelligent clinical operations.Patient recruitment remains the most significant challenge within the Clinical Trials industry. Delays in this process can postpone studies and, ultimately, delay the delivery of life-changing treatments to those in need. Our mission is to hasten this process.By identifying the most effective clinical sites, we facilitate quicker drug market entry. We project that OpenData Clinical will save at least one life annually through the optimization of Clinical Operations.You will be responsible for developing the backbone of our data quality engine and pipelines. Your contributions will enable thousands of curators to efficiently manage extensive datasets with accuracy, providing the life sciences industry with the high-quality data essential for accelerating clinical trials and drug development.This position is ideal for an engineer who prioritizes architectural integrity over quick fixes. You will be part of an engineering-driven culture that values technical excellence and grants true autonomy to innovate.

Join Sopra Steria as a Data Engineer and play a key role in transforming data into actionable insights. You will work with cutting-edge technologies to develop data pipelines, manage data architecture, and ensure data quality. Your expertise will help drive strategic decision-making and improve operational efficiency.

We invite you to submit your CV in English and indicate your English proficiency level.Mindrift offers a unique platform that connects talented specialists with project-based AI opportunities at leading technology firms, focusing on the testing, evaluation, and enhancement of AI systems. Please note that participation is project-based and does not constitute permanent employment.Role OverviewWhile each project presents distinct challenges, contributors can expect to:Design innovative computational engineering problems that replicate genuine engineering processes;Create scenarios that necessitate Python programming to resolve engineering calculations and simulations;Ensure tasks are computationally demanding and require numerical methods or iterative solutions;Develop challenges related to system design, optimization, and analysis;Base scenarios on authentic research challenges or practical engineering applications;Validate solutions using Python with established engineering libraries;Clearly document problem statements and provide verified correct answers.Ideal Candidate ProfileThis position suits engineers proficient in Python who are interested in part-time, non-permanent projects. Ideal candidates will possess:A degree in Mechanical Engineering or a related field;Proficiency in Python for numerical validation. Familiarity with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or any domain-specific programming languages is also acceptable;At least 2 years of professional experience in applied engineering, research, or teaching;A solid understanding of practical engineering limitations and approximations;Strong written English skills (C1+ level);Professional certifications (e.g., CMME, SAS, CAP) and experience in international or applied projects are advantageous.Project WorkflowApplication → Qualification Process → Project Engagement → Task Completion → PaymentProject Time CommitmentFor this project, participants can expect to dedicate approximately 10–20 hours per week during active phases based on project needs. This is an estimate and not a guaranteed workload while the project is active.CompensationContributors on this project can earn up to $31 per hour, depending on their expertise and contribution pace. Compensation will vary by project based on scope, complexity, and required expertise. Please note that other projects on the platform may offer different earnings based on their specific requirements.

At Datavant, we are revolutionizing healthcare through data collaboration. Our mission is to ensure that health data is secure, accessible, and actionable, enabling organizations—from healthcare providers to researchers—to improve patient outcomes. Join our innovative team and contribute to groundbreaking solutions that power the AI revolution in healthcare.Your Opportunity: Be Part of Our Life Sciences Tech Hub in BarcelonaAs we expand our global presence, we're establishing a Life Sciences Tech Hub in Barcelona and are in search of skilled full stack engineers who are passionate about creating impactful healthcare technology. Your role will involve designing and implementing systems that ensure secure, privacy-compliant access to high-quality healthcare data for pharmaceutical companies, biotech innovators, and research institutions worldwide. Your contributions will accelerate clinical trials and improve patient care by making critical data interoperable and trustworthy.At Datavant, you'll have the chance to apply your technical skills and problem-solving expertise in a supportive environment dedicated to our mission: empowering every healthcare decision with the right data, at the right time, in the right format. We seek innovators, dreamers, and doers who are ready to make a difference.Why Join Our Tech Team?Collaborate with engineering leaders on strategies and technology vision.Mentor colleagues through code reviews and software design.Work with a diverse technical stack, including cloud and on-premise solutions, big-data analytics, and complex algorithms.

At Lighthouse, we are on a transformative journey to revolutionize commercial strategies in the hospitality industry. Our advanced commercial platform simplifies data complexity, equipping businesses with actionable insights, sophisticated pricing tools, and state-of-the-art business intelligence—all designed to maximize revenue potential.With $370 million in Series C funding and a relentless drive for growth, we have integrated five companies into our ecosystem and achieved over $100 million in ARR by 2024. Our team of over 850 professionals spans 35 countries and embodies 34 diverse nationalities.At Lighthouse, we prioritize community. We foster a collaborative and enjoyable work culture, passionately working together to redefine the hospitality sector. Are you ready to join us on this exciting journey and shine in one of the industry's most dynamic environments? Your RoleAs a Data Engineer within our newly established Data Products team, you will be instrumental in enhancing the quality and business value of our core data assets. You will take a hands-on approach to design, build, and maintain data pipelines that support various teams at Lighthouse. Acting as the liaison between our data and business needs, you will collaborate with stakeholders to ensure our data serves its users effectively.Your ImpactEstablish expertise in key data products, ensuring thorough understanding of the full data lifecycle, quality, and business applications.Design, implement, and oversee the streaming and batch data pipelines that drive our products and internal analytics.Work directly with data consumers to comprehend their requirements and deliver tailored data solutions.Enhance data quality, latency, and reliability.Adopt a product engineering mindset, centered on delivering value and resolving business challenges through data.Lead our AI evolution by integrating intelligence into our platform. You will not only develop AI features for our clients but also promote an AI-first development culture within the engineering team.Mentor fellow engineers, sharing your knowledge and contributing to their professional growth.Our TeamThe Data Products Team serves as the cornerstone of Lighthouse's data ecosystem, providing the definitive source of truth for our data. Their primary mission is to model and deliver high-quality foundational data products, essential for downstream product features, machine learning models, and data science initiatives across the organization.

About UsConstructor is a pioneering platform revolutionizing search and discovery in the ecommerce sector. We are dedicated to optimizing critical metrics such as revenue, conversion rates, and profit margins. Our search engine is entirely developed in-house, utilizing advanced transformer models and generative large language models (LLMs). This foundational technology empowers various applications, from search functionalities to personalized recommendations and interactive shopping agents. Engineering is our largest department, and we are proud to affirm that our proprietary engine has consistently outperformed competitors in A/B testing, a testament to our commitment to excellence. We are at the forefront of AI innovation, constantly pushing boundaries to maintain our edge in the market.Our engine is designed for extreme scalability, processing over 1 billion queries daily across 150 languages and approximately 100 countries. Our technology supports some of the world's leading ecommerce brands, including Sephora, Under Armour, and Petco.At Constructor, we are a passionate team eager to solve complex challenges and enhance the experiences of our customers and colleagues alike. We prioritize values such as empathy, openness, curiosity, and a commitment to continuous improvement. We believe that empowering everyone within the organization to excel in their roles leads to remarkable outcomes.Founded in 2019 by Eli Finkelshteyn and Dan McCormick, Constructor is a U.S.-based company that continues to thrive under their leadership.About the TeamThe Recommendations team is pivotal in enhancing user experiences for our customers and their end-users. We comprise a dedicated group of cross-functional engineers who thrive on challenges and are committed to improving lives through technology. We uphold values of transparency, curiosity, and continuous refinement in our work, believing that empowering team members to take initiative fosters exceptional results.Our team is focused on advancing traditional product discovery methods while exploring innovative solutions powered by large language models, pioneering a new era of user engagement and innovation.The Recommendations team manages multiple service endpoints and develops our own cloud-deployed solutions using Python, which necessitates leveraging NoSQL databases and interfacing with both internal and external services. Our future roadmap includes transitioning all major developments into high-load distributed services.About the JobThis role primarily involves designing, delivering, and maintaining high-load real-time web services in close collaboration with talented engineers from both the recommendations team and other departments.Develop, deploy, and support robust recommendation services, including I/O-bound web services, CPU-bound services, and data services.Create AWS CloudFormation scripts, Jenkins jobs, and GitHub actions adhering to industry best practices.Establish service observability, monitoring metrics, and alerting mechanisms (using tools like Prometheus and Grafana).

We are seeking a talented and innovative AI/ML Engineer specializing in Python to join our dynamic team at Deel. In this role, you will leverage your expertise in artificial intelligence and machine learning to contribute to cutting-edge projects that enhance our services and solutions. This is an exciting opportunity to be at the forefront of technological advancements in a rapidly evolving industry.

Please submit your CV in English and specify your English proficiency level. Mindrift, in partnership with toloka-ai, connects experienced professionals with project-based work focused on testing and improving AI systems for leading technology companies. This position is a freelance, project-based role, not a permanent staff job. Role overview The Senior Python Developer for Functional Testing Projects will design and implement functional black box tests for large codebases across multiple programming languages. This work involves setting up and maintaining Docker environments, monitoring code coverage, and using LLMs such as Roo Code and Claude Code to streamline development. The role requires familiarity with Linux, Docker, and modern testing tools, as well as experience interpreting code in languages like C, C++, Rust, and Go with LLM support. What you will do Develop functional black box tests for substantial codebases written in different programming languages. Configure and manage Docker environments to ensure reproducible builds and testing across platforms. Track code coverage and set up automated scoring criteria to meet industry standards. Leverage LLMs (such as Roo Code and Claude) to automate tasks, accelerate development, and enhance code quality. Requirements Minimum 5 years as a Software Engineer, focusing primarily on Python. Extensive experience with pytest, including fixtures, session-scoped configurations, and timeouts. Proven skill in creating black-box functional tests for CLI tools. Strong expertise in Docker: writing reproducible Dockerfiles, managing user contexts, and maintaining secure workspaces. Advanced Linux and Bash scripting skills; comfortable debugging in containerized setups. Familiarity with modern Python tools (uv, pyproject.toml, packaging). Ability to read and understand code in C, C++, Rust, and Go, with assistance from LLMs. Experience using LLMs (Claude Code, Roo Code, Cursor) to automate development and generate test cases. English proficiency at B2 level or higher. Preferred qualifications Experience with agent evaluation platforms and MCP CLI. Tools and technologies Python (pytest, uv, Pillow), Docker, Bash, Git Submodules, C/C++/Rust/Go (reading), Dagger, GitHub Codespaces, LLMs (Claude Code, Roo Code, Cursor), coverage.py, gcov, kcov. Benefits and compensation Freelance, project-based assignments through the Mindrift platform powered by Toloka AI. Fully remote with flexible scheduling: set your own hours and work 20-30 hours per week. Compensation depends on project scope and expertise. For this project, AI trainers can earn up to $30 per hour. Location Remote , València, Valencian Community, Spain

Scalian is hiring a Junior Data Engineer to join its team in Madrid or Málaga. This role offers the chance to develop foundational data engineering skills by working directly with experienced colleagues and participating in real-world projects. Role overview This entry-level position centers on learning through hands-on involvement with modern data technologies. The Junior Data Engineer will take part in projects that enhance the company's data infrastructure and processes. What you will do Collaborate with senior engineers and data scientists to design, build, and maintain data pipelines and systems Assist in ongoing projects aimed at strengthening the company’s data capabilities Help develop solutions for better data collection, processing, and utilization Location This position is based in either Madrid or Málaga.

Join Diamond Foundry Inc., a pioneering company at the forefront of technology, dedicated to overcoming the thermal challenges in critical sectors like AI, cloud computing, electric vehicles, and advanced wireless communication (5G/6G). As the creators of the world's first single-crystal diamond wafers, we are on an ambitious journey to integrate diamond technology into every chip. With $515 million in funding and a robust multi-billion dollar expansion strategy, we are innovating one of the most sustainable manufacturing processes, transforming greenhouse gases into diamond wafers using zero-emission energy.We are looking for an experienced and proactive Senior Data Systems Engineer (Networking) to enhance our global IT team at Diamond Foundry. Located in Zaragoza, this role will position you as the leading network expert within our organization. You will support Tier-1 manufacturing and office environments worldwide, collaborating closely with our primarily U.S.-based IT team to maximize production uptime, facilitate rapid site expansion, and bolster network resilience across all operational regions.

As a Data Engineering Manager at Airalo, you will lead a dynamic team of data engineers in designing and implementing robust data solutions that empower our business analytics and decision-making processes. You will collaborate closely with cross-functional teams to ensure the effective use of data across various platforms, optimizing performance and scalability.Your role will involve mentoring team members, managing projects, and driving innovation in data engineering practices. If you are passionate about data and have a vision for the future of data engineering, we want to hear from you!

Join Altersolutions as a Python Developer and be part of a dynamic team in Madrid! We are looking for passionate and talented individuals to contribute to exciting projects and drive innovation.

Experian is looking for a Senior Data Scientist to join the team in Madrid. This position centers on developing predictive models and shaping data strategies that support business goals. Role overview As a Senior Data Scientist, collaboration with colleagues from different departments will be a regular part of the job. The work involves analyzing data, building models, and providing insights that help guide key decisions across projects. What you will do Create and refine predictive models to support business operations Work closely with cross-functional teams to design and implement data-driven strategies Translate analytical findings into actionable recommendations for ongoing projects Impact The insights and solutions produced in this role will play a direct part in shaping project outcomes and improving decision-making processes at Experian.

Veeva Systems is a purpose-driven leader in industry cloud solutions, dedicated to empowering life sciences companies to expedite the delivery of therapies to patients. As one of the quickest-growing SaaS companies in history, we achieved remarkable growth, surpassing $2B in revenue last fiscal year, with an exciting trajectory ahead.Our core values prioritize integrity, customer satisfaction, employee well-being, and speed. Uniquely, we made history in 2021 by becoming a public benefit corporation (PBC), which legally binds us to balance the interests of our customers, employees, society, and investors.Being a Work Anywhere company, we offer the flexibility to work from home or in the office, enabling you to succeed in your ideal workspace.Join us in transforming the life sciences industry, and making a meaningful difference for our customers, employees, and communities.The RoleAt Veeva Link, we are developing the intelligence layer for life sciences, crafting interconnected data applications that speed up drug development and enhance patient outcomes. Our fundamental belief is that merging top-tier data with cutting-edge software provides immense value.Execution is paramount. We believe that progress is driven by speed, precision, and quality in our daily endeavors. Our engineering philosophy focuses on clear product definitions that lead to thorough technical designs. We utilize a modern tech stack to create inherently dependable applications that deliver an exceptional user experience.Our work encompasses two essential domains:Data-Driven InsightsWe build advanced applications that map and analyze global scientific and medical expertise, delivering impactful insights and AI-driven intelligence. Our engineers tackle challenging data modeling, entity resolution, and sophisticated machine learning tasks.Intelligent Business WorkflowsWe design automated workflows that streamline business processes, enhancing efficiency and collaboration across teams.

Plain Concepts seeks a QA Automation Engineer with strong Python skills. This remote role is open to candidates based in Barcelona, Catalonia, Spain. The main goal: improve product reliability by advancing automated quality assurance. Key responsibilities Collaborate with development teams to design and implement automated tests for company products Identify system weaknesses and suggest actionable improvements Help refine and enhance testing strategies and processes Location This is a fully remote position. The core team operates from Barcelona, Catalonia, Spain.

Role Overview Rover is hiring a Senior Data Analyst in Barcelona. This role focuses on turning complex data into insights that shape decisions across the company. The Senior Data Analyst works closely with teams to support product and service improvements through strong analytical skills. What You Will Do Analyze large and varied data sets using advanced techniques Translate raw data into clear, actionable recommendations Support strategic initiatives by providing data-driven guidance Collaborate with colleagues across different departments Help teams use data to solve challenging problems Who We’re Looking For Experience interpreting and analyzing complex data Comfort working in a collaborative, cross-functional setting Strong communication skills for sharing insights with both technical and non-technical teams Desire to work on challenging analytical projects This position is based in Barcelona.