Position Overview

We are seeking an Embedded Software Engineer to develop and maintain the company’s embedded software solutions, working with microcontrollers, RTOS environments, and data-driven tools to support testing, validation, and production systems.

Key Responsibilities:

• Develop and maintain software for the company’s devices.
• Program ARM microcontrollers in C/C++ within RTOS environments.
• Develop testing tools and test benches using Python.
• Process and analyze test data and results for evaluation and validation.
• Develop reporting systems, real-time visualizations, and dashboards.
• Integrate software with production management tools and systems.
• Implement and manage communication protocols including RF, Ethernet, USB, SPI, I2C, and UART.
• Participate in code reviews and ensure software quality.
• Manage technical documentation and version control using Git/GitLab, including submodules and collaborative workflows.
• Contribute to continuous improvement of team processes and methodologies.

Qualifications

Education:

Bachelor’s degree in Electronic Engineering, Computer Engineering, Telecommunications, or a related field.

Experience:

• Experience in embedded software development for microcontrollers and RTOS environments.
• Experience programming in C/C++.
• Experience developing tools and scripts in Python.
• Experience in data processing and analysis.
• Experience developing visualization, reporting, or dashboard tools.
• Experience with Git/GitLab and collaborative development workflows.

Preferred Qualifications:

• Knowledge of FPGA development and related technologies.
• Experience or interest in Artificial Intelligence and Machine Learning, particularly for data analysis, anomaly detection, and models based on PyTorch or TensorFlow.

Soft Skills:

• Proactive, autonomous, and results-oriented mindset.
• Strong analytical and problem-solving skills.
• Good communication skills and ability to work effectively in a team.
• Fluent level of English.

Technology Stack:

• C/C++
• Python
• ARM microcontrollers
• RTOS environments
• Git / GitLab
• Communication protocols: RF, Ethernet, USB, SPI, I2C, UART

Physical Requirements

Ability to work in a standard office environment and use a computer for extended periods.

This job description may not be inclusive to the duties and responsibilities listed. Additional tasks may be assigned to the employee from time to time or the scope of the job may change as needed by business demands. 

Wallapop is a Barcelona based scale-up driven by the purpose to empower people to embrace a more conscious and human way of consumption. We believe in a world where collaborative economy is mainstream. This is what drives us. 💫

Wallapop operates in Spain, Italy and Portugal, offering a catalogue of several hundreds of millions of products and services. Powered by technical innovation and continuous improvement, we bring together the scale & trust of classifieds with the marketplace’s convenience & reach. 🌱 Our mission is to enable a connected trade ecosystem, making 2nd-hand the norm through smart use of technology.

The Challenge 🧩 

Wallapop generates billions of data points daily. With a mature data infrastructure already in place, our Data Science and Machine Learning area is gaining significant momentum. As we scale, we face the exciting challenge of taking our ML Platform to the next level to support complex solutions in Personalization, Search, Trust & Safety, and Logistics. As a Senior ML Engineer, you will lead the evolution of our ML Platform and MLOps practice. You will partner with Data Scientists, Data Engineers, and DevOps to shape a vision that balances innovation with reliability, ensuring our models scale efficiently to serve millions of users.

What You Will Do 👇

• Iterate and maintain Wallapop’s ML Platform, identifying opportunities to improve speed, reliability, and maintainability. You will define the long-term vision and roadmap for MLOps.
• Work hand-in-hand with Data Scientists to support their efforts, ensuring they have the tooling to develop, deploy, and monitor scalable models efficiently.
• Define and promote engineering best practices (coding standards, testing, CI/CD) within the ML domain.
• Partner with Data Engineering and DevOps to align ML development with company-wide infrastructure and data governance standards.
• Investigate and integrate new frameworks and tools (e.g., for LLMs or real-time inference) to keep our stack modern and effective.

What We’re Looking For 🔎

• Proven experience building and owning production-ready ML platforms and pipelines. You understand the full lifecycle from experimentation to monitoring.
• Deep understanding of AWS components (SageMaker, Lambda, S3) and container orchestration with Kubernetes.
• Strong software engineering background with proficiency in Python, Git, and CI/CD workflows. You write robust, testable code.
• Experience with real-time ML architectures, leveraging tools like Kafka for low-latency ingestion and inference.
• Hands-on experience with vector databases or semantic search infrastructure (e.g., OpenSearch, Vertex AI), including indexing and retrieval tuning.
• Familiarity with the broader ML toolkit, such as orchestration/tracking tools (Flyte, MLFlow, Feast) and standard libraries (Pandas, Scikit-learn, TensorFlow/PyTorch).
• Professional proficiency in English, with the ability to explain complex technical concepts to diverse stakeholders.

What Would Be A Plus 🚀

• Hands-on experience working with LLMs, RAG architectures, and libraries like LangChain or LlamaIndex.
• Familiarity with Big Data technologies like Spark or Beam.
• Experience with Data Engineering tools such as Airflow, dbt, or Datahub.
• Experience with other cloud platforms like GCP or Azure in addition to AWS.

Do note that all our jobs are 📍 Barcelona based. We follow a hybrid model where flexibility rules. We commit to a minimum of 6 days per month in the office. Each team self-organizes to decide on cadence and in-person/remote rituals.

Wallapop is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees as we want Wallapop to be a place for everyone.

Additionally to the opportunity to contribute to an agile product set up and work together towards achieving our meaningful mission, we offer the following 🍭 Perks & Benefits:

• Generous individual learning budget of 2k per year
• Free office meals, lunch selection from different providers
• Group and individual English, Catalan & Spanish lessons as part of our working day
• Private Health Insurance with Alan
• Flexible working hours + intensive Fridays
• Flexible remuneration to deduct from gross salary (kindergarten/food/transport check)
• Gym & Wellness plan, including physiotherapist in the office
• Generous referral Program & Charity Donation
• Bonus for weddings & newborns
• Wallapop Renta (Tax income support)
• Monthly plan for free shipping, bumps & home-pick-up on our services
• Work anniversary Gifts and Birthday Surprises
• Contribution towards your WIFI in your monthly payroll
• One-off payment based on compensation package to go towards setting up your home office
• Relocation package (monetary support and legal advice) and visa sponsorship, if applicable
• 26 holidays per year
• TOP hardware of your choice (latest Apple or Windows)

What does the hiring process for this position look like? 👀 **Please, note that all interviews take place remotely over hangouts.**

• Intro Call - run by Talent Acquisition, focus on providing more information about the role and the company as well as going over your experience, motivation, and expectations. This usually takes 45-60 minutes.
• Technical Task - you will be assigned a challenge to assess the technical skills required for the role.
• Expertise Interview - run by the core team, focusing on the hard skills and the ability to deliver in a given context. This usually takes 60-90 minutes.
• Stakeholder Interview - run by the hiring team and relevant stakeholders, focus on the ability to collaborate & deliver in a cross-functional set-up. This usually takes 60 minutes.
• Culture-Add Interview - run by culture interviewers, focus on adherence to Wallapop's purpose and business proposition. This usually takes 60 minutes.
• Offer - should you be the right candidate, your offer will be discussed over a call with talent acquisition and will then be confirmed in writing.

We are looking for a Senior MLOps Engineer to add to our Data team in Barcelona.

Join the User Acquisition MLOps team that builds the core ML backbone of Appodeal. We design and run the systems that power real-time predictions at massive scale, where every millisecond matters. Our work directly drives thousands of bidding operations each second, supporting a high‑throughput, low‑latency inference platform used across the company.

You will help shape and evolve a modern ML platform built around Databricks, MLflow, Unity Catalog, GitHub Actions, and deep integrations with our Predictor service. This means solving real engineering challenges: scaling training pipelines, optimizing GPU workloads, ensuring safe and automated model promotions, and keeping online inference reliable under extreme load.

You will collaborate daily with Data Science, Data Engineering, Runtime, DevOps, and Product, and you will fully own the systems and projects you touch. This is a role for engineers who like autonomy, impact, and building things that matter.

Responsibilities:

• Design, operate, and improve the ML platform, including Databricks workflows for training, MLflow and Unity Catalog for model management, CI/CD pipelines using GitHub Actions and Databricks Asset Bundles, and integration with the runtime inference layer.
• Support data scientists in developing and maintaining end-to-end training pipelines, covering data processing, feature transformations, ML model training on GPUs, and distributed training setups to ensure efficient and scalable workflows.
• Ensure reliable and safe model inference by validating models before promotion, checking metadata compatibility, monitoring latency, and supporting model evaluation flows.
• Maintain strong ML observability, including online and offline monitoring, data and feature parity checks, and automated validation of model performance in production.
• Develop internal tools and APIs that enable DS teams and account managers to experiment, validate, and promote models efficiently while reducing operational friction.

Requirements:

• 3+ years of experience in MLOps, ML Platform Engineering, or Backend roles supporting production ML systems.
• Strong Python and software engineering skills, with experience building and maintaining APIs (FastAPI, Flask, or similar).
• Hands-on experience with DNNs using PyTorch or other modern deep learning frameworks, including GPU training and optimizing hardware utilization.
• Solid understanding of distributed computing and data processing using Apache Spark or similar frameworks.
• Experience with Databricks (Jobs, MLflow, Delta, UC) or an equivalent cloud-based ML platform.
• Strong understanding of the ML lifecycle: data ingestion, experimentation, model packaging, deployment, and monitoring.
• Familiarity with real-time model inference systems and ensuring compatibility with downstream services.
• Experience with data validation libraries (Pydantic or similar) used within ML and API workflows.
• Good understanding of Docker containers, Kubernetes, and basic networking concepts.
• Experience creating and maintaining CI/CD pipelines (GitHub Actions or similar).
• Experience with orchestration tools (Databricks Jobs, Dagster, Airflow or similar).
• Demonstrated ability to use modern AI tools (Claude, ChatGPT, Gemini) to improve development speed and quality.
• Proactive mindset with a strong sense of ownership, consistently pushing work forward and anticipating next steps without needing close direction.
• Strong English communication skills.

Nice to have:

• Exposure to very high-load, low-latency ML inference environments.
• Knowledge of distributed or large-scale ML training frameworks and multi-GPU setups.
• Familiarity with Databricks Asset Bundles.
• Understanding of ONNX or other portable model serialization formats.
• Ability to work with Rust programming language.
• Familiarity with transformer architectures, encoder-decoder models, or sequence modeling approaches.
• Exposure to data engineering concepts, such as building scalable data pipelines, understanding CDC patterns, or working with structured and unstructured datasets.
• Experience with MinIO or other S3-compatible storage systems.
• Understanding of networking protocols such as TCP, HTTP, and gRPC, including their limitations in low-latency scenarios.
• Confidence navigating the Atlassian ecosystem (Jira, Confluence, Compass).

This position supposes relocation to Barcelona and work from our office in the city center.

Why Join Us:

• Opportunity to work on cutting-edge projects with a global impact in the mobile app industry.
• A collaborative and inclusive work culture that values innovation and continuous learning.
• Competitive salary, flexible work arrangements, and a comprehensive benefits package.
• Professional development opportunities and career growth prospects within a fast-growing company.

We are now expanding our data capabilities and seeking an experienced Head / Director of Data Science to lead and scale our Data Science UA team function in Barcelona.

This role is ideal for a leader with a strong technical background, excellent people-management skills, and the ability to turn data into actionable, high-impact product and business outcomes.

Role Overview:

The Head / Director of Data Science will be responsible for building and growing our Data Science organization, driving advanced analytics and ML initiatives, and ensuring our products and business units are empowered by high-quality insights and predictive capabilities.

You will work closely with Product, Engineering, Revenue, and Leadership teams to translate business needs into DS/ML solutions, strengthen our data infrastructure, and support decision-making across the ecosystem.

This is a strategic and hands-on leadership role with significant influence on product evolution, optimization algorithms, and operational excellence.

Key Responsibilities:

Leadership & Strategy

• Lead and scale the Data Science function across the organization.
• Translate business and product goals into clear DS/ML initiatives and execution plans.
• Build and promote a strong data-driven culture across all teams.
• Applied Data Science & ML.
• Oversee development, deployment, and monitoring of ML models across Appodeal’s product and monetization ecosystem.
• Guide experimentation, modeling, uplift measurement, and algorithmic optimization.
• Ensure model quality, reliability, fairness, and performance at scale.
• Collaboration & Stakeholder Management.
• Partner with Product and Engineering teams to integrate Data Science into product roadmaps.
• Work with business units to identify opportunities, define DS/ML requirements, and deliver impactful insights.
• Communicate DS outcomes, metrics, and recommendations to leadership.

Team Leadership

• Lead, mentor, and develop a multidisciplinary team of Data Scientists, Analysts, and ML/AI specialists.
• Foster knowledge sharing, best practices, experimentation, and continuous improvement.
• Drive hiring, talent development, and team structure optimization.

Data Infrastructure & Governance

• Collaborate with Data Engineering and MLOps teams to ensure robust pipelines, feature stores, and model deployment workflows.
• Improve data quality, observability, and governance standards.

Qualifications:

Education

Bachelor’s or Master’s degree in Data Science, Computer Science, Engineering, Math, or a related field (PhD is a plus).

Experience

• 5+ years of experience in Data Science, Machine Learning, or Applied Analytics.
• 3+ years in a DS leadership role (Lead DS, Head of DS, Director of DS, or similar).
• Demonstrated experience building and leading Data Science teams.
• Proven track record of delivering DS/ML solutions with real business impact.

Technical Skills

• Strong understanding of ML algorithms, experimentation, predictive modeling, and statistical analysis.
• Hands-on experience with Python, ML frameworks (TensorFlow, PyTorch, Scikit-learn), and analytics tooling.
• Solid understanding of data pipelines, big data technologies, and collaboration with Data Engineering teams.
• Experience with AdTech, attribution, auction mechanics, or optimization algorithms is a strong plus.

Leadership & Soft Skills

• Excellent stakeholder management and communication skills.
• Ability to translate technical concepts into business language.
• Strong decision-making and prioritization abilities.
• Passion for mentoring, coaching, and building high-performing teams.

What We Offer:

• Opportunity to build and lead the Data Science function of a global product company.
• Direct influence on product roadmap and business outcomes.
• Collaborative and international team environment.
• Competitive compensation package and growth opportunities.
• A chance to shape the future of mobile app monetization.

WHO WE ARE 🌍

We help creators get more out of every conversation with Instagram-focused automations and support for other channels like Messenger, WhatsApp, and TikTok. The result? Better engagement, more sales, and real, sustainable growth.

With a diverse team of 350+ people spread across three continents, we’re building the leading Chat Marketing platform that is used — and loved — by more than 1.5 million customers worldwide.

WHO WE'RE LOOKING FOR 🌟

Manychat’s AI Core team turns ML and LLM ideas into production features used in millions of conversations every day. You will work across applied research, prototyping, and production delivery, partnering closely with our Python Platform team and Product to validate ideas quickly and ship high-impact AI workflows.

This role suits someone who loves to build fast, experiment, and take ownership of models, agents, and workflows end to end.

WHAT YOU’LL DO 🤖

• Design and deliver ML/LLM solutions end-to-end: fast prototyping, offline evaluation, and production rollout of models and agent workflows.
• Build and iterate on AI agents (RAG, vector search, memory, tools) using clear benchmarks and product metrics to guide improvements.
• Choose and implement the right approach for each problem (classical ML, LLMs, RAG pipelines, or agent architectures), defining data and labeling needs where required.
• Work closely with the Python Platform team to productionize your solutions with clean service boundaries, monitoring, and scalability in mind.

TO SHINE IN THIS ROLE 💥      

          Machine Learning & LLM Expertise

• Solid understanding of ML algorithms, metrics, search, RAG, and agent design. 
• Experience with frameworks like LlamaIndex, LangChain, or similar.
• Hands-on tuning with PyTorch, TensorFlow.
• Experience with LLM evaluation and benchmarking.
  
  Engineering Skills
• Strong Python engineering background, ideally three or more years in production environments.
• Experience building backend services (FastAPI, Docker, Pydantic, PostgreSQL).
• Familiarity with cloud environments and monitoring is a strong plus.
  
  Collaboration & Ownership
• Clear communication in English.
• Ability to work independently, iterate fast, and collaborate with product, data, and engineering teams.
• Product mindset and comfort working in a fast-moving environment.

WHAT WE OFFER 🤗

We care deeply about your growth, well-being, and comfort:

• 🌍 Hybrid onboarding to start work remotely and relocation support for you and your family.
• 💙 Comprehensive health insurance for both you and your family.
• 📚 Professional development budget for conference tickets, online courses, and other relevant resources to help you grow.
• 🫶 Flexible benefits package to tailor perks that matters most for you.
• 🪴 Hybrid work and generous leave options to prioritize your work-life balance.
• 🍽️ In-office perks, including free meals and snacks.
• 🤝 Company-funded sport activities, annual offsites and team-building events.

Manychat is an Equal Opportunity Employer. We’re committed to building a diverse and inclusive team. We do not discriminate against qualified employees or applicants because of race, color, religion, gender identity, sex, sexual preference, sexual identity, pregnancy, national origin, ancestry, citizenship, age, marital status, physical disability, mental disability, medical condition, military status, or any other characteristic protected by local law or ordinance.

This commitment is also reflected through our candidate experience. If you have individual needs that may require an accommodation during the interview process, please indicate this in your application. We will do our best to provide assistance throughout your interview process to ensure you’re set up for success.

With my application, I accept the Manychat Privacy Policy.

WHO WE ARE 🌍

We help creators get more out of every conversation with Instagram-focused automations and support for other channels like Messenger, WhatsApp, and TikTok. The result? Better engagement, more sales, and real, sustainable growth.

With a diverse team of 350+ people spread across three continents, we’re building the leading Chat Marketing platform that is used — and loved — by more than 1.5 million customers worldwide.

WHO WE'RE LOOKING FOR 🌟

Manychat’s AI Core team turns ML and LLM ideas into production features used in millions of conversations every day. You will work across applied research, prototyping, and production delivery, partnering closely with our Python Platform team and Product to validate ideas quickly and ship high-impact AI workflows.

This role suits someone who loves to build fast, experiment, and take ownership of models, agents, and workflows end to end.

WHAT YOU’LL DO 🤖

• Design and deliver ML/LLM solutions end-to-end: fast prototyping, offline evaluation, and production rollout of models and agent workflows.
• Build and iterate on AI agents (RAG, vector search, memory, tools) using clear benchmarks and product metrics to guide improvements.
• Choose and implement the right approach for each problem (classical ML, LLMs, RAG pipelines, or agent architectures), defining data and labeling needs where required.
• Work closely with the Python Platform team to productionize your solutions with clean service boundaries, monitoring, and scalability in mind.

TO SHINE IN THIS ROLE 💥     

          Machine Learning & LLM Expertise

• Solid understanding of ML algorithms, metrics, search, RAG, and agent design. 
• Experience with frameworks like LlamaIndex, LangChain, or similar.
• Hands-on tuning with PyTorch, TensorFlow.
• Experience with LLM evaluation and benchmarking.
  
  Engineering Skills
• Strong Python engineering background, ideally three or more years in production environments.
• Experience building backend services (FastAPI, Docker, Pydantic, PostgreSQL).
• Familiarity with cloud environments and monitoring is a strong plus.
  
  Collaboration & Ownership
• Clear communication in English.
• Ability to work independently, iterate fast, and collaborate with product, data, and engineering teams.
• Product mindset and comfort working in a fast-moving environment.

WHAT WE OFFER 🤗

We care deeply about your growth, well-being, and comfort:

• 🌍 Hybrid onboarding to start work remotely and relocation support for you and your family.
• 💙 Comprehensive health insurance for both you and your family.
• 📚 Professional development budget for conference tickets, online courses, and other relevant resources to help you grow.
• 🫶 Flexible benefits package to tailor perks that matters most for you.
• 🪴 Hybrid work and generous leave options to prioritize your work-life balance.
• 🍽️ In-office perks, including free meals and snacks.
• 🤝 Company-funded sport activities, annual offsites and team-building events.

Manychat is an Equal Opportunity Employer. We’re committed to building a diverse and inclusive team. We do not discriminate against qualified employees or applicants because of race, color, religion, gender identity, sex, sexual preference, sexual identity, pregnancy, national origin, ancestry, citizenship, age, marital status, physical disability, mental disability, medical condition, military status, or any other characteristic protected by local law or ordinance.

This commitment is also reflected through our candidate experience. If you have individual needs that may require an accommodation during the interview process, please indicate this in your application. We will do our best to provide assistance throughout your interview process to ensure you’re set up for success.

With my application, I accept the Manychat Privacy Policy.

We are looking for an experienced Lead Data Scientist to add to our Data Science team.

Responsibilities:

• Drive the team’s data science vision and ensure alignment with business goals, focusing on ad-tech and revenue optimization.
• Guide and support the growth of data scientists, fostering a collaborative and innovative environment.
• Oversee the development of scalable, high-impact models for ad targeting, bid strategy, and performance analysis.
• Ensure the efficiency and relevance of data pipelines and models, adapting to the dynamic tech landscape.

Technology Stack:

• Proficiency in Python and SQL.
• Experience with manipulation frameworks such as PySpark and Pandas.
• Skilled at using cloud services such as AWS, etc.
• Hands-on experience in DNN models training libraries and frameworks (PyTorch, Hydra, comet etc.)

Qualifications:

• Bachelor's or Master's degree in Computer Science, Statistics, Mathematics, or a related field.
• 5+ years of experience in data science, preferably in a product-focused environment.
• 2+ years experience in AdTech.
• 2+ years experience in a leading role.
• Strong analytical skills with the ability to derive insights from complex datasets.
• Proficiency in statistical modeling and machine learning techniques.
• Excellent communication and collaboration skills, with the ability to work effectively in a cross-functional team environment.
• Based in Barcelona, Spain or ready for relocation.

Why Join Us:

• Opportunity to work on cutting-edge projects with a global impact in the mobile app industry.
• A collaborative and inclusive work culture that values innovation and continuous learning.
• Competitive salary, flexible work arrangements, and comprehensive benefits package.
• Professional development opportunities and career growth prospects within a fast-growing company.