Senior Fullstack Engineer (Python + React.js) in London

Senior Fullstack Engineer

Who is Parser?

Technology alone does not create impact—the right teams do.

Founded in 2018, Parser is a boutique technology services and consulting firm helping global organisations solve complex business challenges through digital transformation, product development and AI enablement.

We are a fast-growing team of 340+ engineers and consultants across Europe (UK, Spain, Portugal), the Americas (US, Argentina, Uruguay, Colombia), and the Middle East.

We combine global reach with a mindset focused on agility, senior expertise, and close collaboration.

We work as an extension of our clients’ teams, helping them define the right problems, shape solutions, and deliver technology-driven outcomes that create measurable business value.

Our expertise spans software engineering, AI & data, product development, and customer experience, delivered by teams that combine strong technical depth with a consulting mindset.

Why Join Us?

If you are looking for a place where you can think beyond execution, take true ownership of outcomes, influence decisions, and continuously learn alongside top‑tier specialists in a truly global environment, we’d love to meet you.

How will you impact?

We are looking for a highly skilled Fullstack Engineer to design, develop, and maintain scalable, secure, and efficient server‑side applications.

The ideal candidate should have experience in microservices architecture, API development, database management, and frontend ensuring high availability and performance of backend and frontend services.

A strong focus on Separation of Concerns (So C), security best practices, and
performance optimization is crucial for success in this position.

Your key responsibilities

• Integrate models into backend systems and create API endpoints for model interaction (e. g., retrieving predictions).
• Develop and maintain scalable services, e. g. Microservices utilising REST, g RPC, or Graph QL, ensuring optimal performance and seamless integration.
• Optimize database queries and schemas to improve performance, scalability, and reliability.
• Implement security features, including authentication and authorization using industry‑standard practices.
• Develop and maintain web interfaces using React JS
• Implement and maintain state management using tools such as Redux or React Query
• Collaborate with frontend developers to ensure efficient API integration and a seamless user experience.
• Troubleshoot and resolve production issues, ensuring high availability and minimal downtime.
• Write unit and integration tests to maintain code reliability and ensure high‑quality releases.
• Continuously monitor and optimize backend performance using observability tools such as Datadog, Cloud Watch or similar.
• Participate in design discussions and decision‑making to enhance system
  robustness and scalability.
• Maintain technical documentation to ensure clear communication of system
  capabilities and updates.

What you’ll bring to the role

• Bachelor degree in Computer Science, Software Engineering, or any related field is required, or equivalent practical experience.
• Minimum 8 years of experience in backend development, with a strong focus on building scalable, high‑performance systems.

Technical Skills

• Python expertise, with hands‑on experience building backend services and APIs using Fast API, Flask or similar.
• Experience in designing and developing end‑to‑end (E2E) tests to ensure smooth integration between backend and frontend components.
• A solid understanding of microservices architecture, event‑driven systems, and service‑oriented design patterns.
• In‑depth knowledge of SQL databases (e. g., Postgre SQL, My SQL) and No SQL databases (e. g., Mongo DB) for data management and optimization.
• Experience with ETLs and data transformation
• Solid expertise in HTML, CSS, Java Script, and React JS.
• Extensive experience with cloud platforms such as AWS including services for database hosting, API management, and serverless computing.
• Proficiency with Docker for containerization and orchestration tooling such as ECS (Amazon Container Services), enabling scalable application deployment.
• Hands‑on experience with API security protocols, including JWT, OAuth2, and Open ID Connect, Active Directory (now Microsoft Entra ID) to secure sensitive data and control access.
• Proficiency with Git for version control, Git Hub Actions and CI/CD pipelines to automate and streamline development workflows.
• Proficiency with performance tuning and scalability techniques, such as load balancing, caching, and database indexing.

Soft Skills

• Strong analytical and problem‑solving skills, with the ability to quickly assess and address technical challenges.
• Excellent communication skills, both written and verbal, for collaborating with cross‑functional teams and documenting technical solutions.
• A proactive, self‑motivated approach to addressing issues and driving improvements in backend systems.
• A strong commitment to continuous learning and staying up‑to‑date with emerging technologies and industry best practices.

Nice‑to‑Have Qualifications

• Familiarity with message brokers such as Kafka, or AWS SQS for handling asynchronous communication.
• Experience with Infrastructure as Code (Ia C) tools like Terraform or Cloud Formation for managing cloud infrastructure.
• Knowledge of observability and monitoring tools, such as Cloud Watch or Datadog, to track and troubleshoot system performance.
• Familiarity with serverless architectures (e. g., AWS Lambda) and event‑driven programming paradigms.
• Exposure to Agile/Scrum methodologies and tools like Jira for managing tasks and sprint planning.
• Certifications in cloud technologies, such as AWS Certified Developer.
• Manage, host, and serve AI/ML models (MLOps), by ensuring their scalability, reliability, and performance in production environments.

Location

• Candidates based in Spain: flexible remote work, with availability to travel to the UK office in Hayes, West London, once per month.
• Candidates based in UK/London: Hybrid model, 2-3 days per week in the office at Hayes, West London

You will receive

• The chance to join an organization with triple‑digit growth that is changing the paradigm on how software products are built.
• The opportunity to form part of an amazing, multicultural community of tech experts.
• A highly competitive compensation package.
• Medical insurance.

Parser is committed to fostering an inclusive workplace and providing equal employment opportunities to all applicants regardless of race, religion, gender, sexual orientation, age, disability, or any other protected characteristic under applicable law.

If you require reasonable accommodations during the recruitment process, please let us know and we will work with you to support your participation.

By applying to this role, you acknowledge that your personal data will be processed in accordance with Parser’s Privacy Notice for recruitment purposes.

Parser may use AI‑assisted tools during certain stages of the recruitment process to support operational efficiency.

Our recruiting teams use AI to streamline note‑taking and scheduling.

All hiring decisions are made by people, with human review and oversight.

Come and join our #Parser Community.

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