Senior Software Engineer

Syntho; Amsterdam; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Cutting-edge tech

Ambitious team

State-of-the-art technologies

Startup culture

Team outings

Job summary

Syntho, based in Amsterdam, is seeking a Senior Software Engineer to help grow our cutting-edge synthetic data platform. You will work across frontend and backend, tackle distributed computing challenges, and improve performance, reliability, and maintainability of our stack.

You will apply SOLID, DRY, and modern patterns with FastAPI, Django (legacy) and Next.js, using Ray.io, PostgreSQL, Docker, and Kubernetes.

Qualifications

• Strong CS fundamentals and distributed computing knowledge.
• Proficient in Python for backend development.
• Experience with FastAPI and Django authentication/authorization.
• Front-end experience with ReactJS and Next.js.
• Strong PostgreSQL expertise and query optimization.
• Familiar with Ray.io or similar distributed frameworks.
• Experience with Docker, Kubernetes, CI/CD and DevOps.

Responsibilities

• Design, develop, and optimize frontend and backend components.
• Build production-ready features end-to-end.
• Address technical debt and refactor inefficient code.
• Apply engineering best practices (SOLID, DRY, Clean Code).
• Write unit and integration tests across layers.
• Improve observability, monitoring, and debugging tools.
• Collaborate to define architectural improvements.
• Work with Ray.io to scale distributed tasks.
• Optimize PostgreSQL queries and indexing.

Skills

Python

FastAPI

Django

JavaScript/TypeScript

ReactJS

PostgreSQL

Docker

Kubernetes

Ray.io

Async programming

Distributed computing

Scalable architecture

CS fundamentals

Tools

Celery/Redis

Alembic

Next.js

Job description

Company Information

Syntho is a data technology organization with a strong expertise in synthetic data, headquartered in Amsterdam, Netherlands. It was founded in 2020 with the goal of solving the global privacy dilemma and enable the open data economy, where data can be used and shared freely and privacy guaranteed. We offer privacy-preserving synthetic data to unlock your data and take away legitimate privacy concerns. As a startup, Syntho has ambitious plans in the upcoming years and is growing really fast. Want to grow your career and be at the forefront of data-driven innovation? Then we’re looking for you!

Role Description

We are looking for a Senior Software Engineer to join our team and help improve our rapidly growing application. You will work across all layers of our technology stack, solving complex challenges related to distributed computing, performance optimization, and software maintainability. Your contributions will directly impact the scalability, reliability, and efficiency of our platform.

What’s in it for you

• Opportunity to work on a cutting-edge distributed computing platform.

• Solve real-world challenges related to performance, scalability, and maintainability.

• Working with a young & ambitious team that values software engineering best practices.

• Work with state-of-the-art technologies and become front-runner with the latest (AI) developments.

• Doing good – contribute in solving one of the key global challenges: the data / privacy dilemma.

• Regular team outings and Friday company catch-ups and drinks.

• An awesome startup culture of responsibility and freedom to turn your ambition into reality.

Key Responsibilities

• Design, develop, and optimize both frontend and backend components, ensuring clean, maintainable, and efficient code.

• Capable of developing production-ready features from front to back

• Address technical debt, refactor inefficient code, and resolve memory overflow issues.

• Implement software engineering best practices (SOLID, DRY, Clean Code, Design Patterns, etc.).

• Write and maintain unit and integration tests for all application layers.

• Improve system observability, monitoring, and debugging tools.

• Collaborate with other engineers and stakeholders to define best practices and architectural improvements

• Our technology stack consists of: Ray.io, FastAPI, Celery/Redis, Alembic, Django (being discontinued), and NextJs, the person for this position should be capable of engineering solutions using this technology stack with least friction, or in similar ones.

• Usual tasks to be performed within the technology stack:

  • Enhance and maintain our FastAPI-based web API and help discontinue our Django authentication and authorization layer by adding this support to FastAPI itself.

  • Improve and extend our Next.js/ReactJS frontend, ensuring a smooth user experience.

  • Work with Ray.io to optimize and scale our distributed computing tasks.

  • Optimize PostgreSQL database queries and indexing for high performance.

Requirements

• Strong knowledge of computer science fundamentals, including algorithms, data structures, concurrency, and distributed computing.

• Proficiency in Python for backend development.

• Experience with FastAPI and Django (authentication & authorization).

• Proficiency in JavaScript/TypeScript, particularly with ReactJS and Next.js.

• Strong experience with databases and PostgreSQL, including query optimization.

• Familiarity with Ray.io or similar distributed computing frameworks.

• Solid understanding of asynchronous programming and parallel processing.

• Experience in designing scalable and maintainable software architectures.

• Strong problem-solving skills and ability to work on complex technical challenges.

• Excellent communication and collaboration skills.

• Experience refactoring large-scale applications and resolving performance bottlenecks.

• Knowledge of containerization (Docker, Kubernetes).

• Experience with CI/CD pipelines and DevOps practices.

Preferred Qualifications

• Familiarity with message queues (e.g., Redis, RabbitMQ, Kafka).

• Experience leading engineering teams or mentoring junior developers.