About the job
Please submit your CV in English and indicate your English proficiency level.
This Senior Python Systems Developer role is a project-based, freelance opportunity with Toloka AI (via Mindrift), supporting top technology companies in testing and improving AI systems. The position is remote and based in Stuttgart, Baden-Württemberg, Germany, but open to candidates working from anywhere.
Role overview
This position centers on building and maintaining functional black box tests for large and diverse codebases. Responsibilities include managing Docker environments, using language models to interpret code in C, Rust, and Go, and translating migration requirements into actionable development tasks. Tools such as Roo Code and Claude Code are used to streamline workflows and automate repetitive tasks.
What you will do
- Design and implement functional black box tests for projects written in multiple programming languages.
- Set up and manage Docker environments to ensure reproducible builds and consistent testing across platforms.
- Monitor code coverage and automate scoring to meet industry standards.
- Apply large language models (LLMs) like Roo Code and Claude to accelerate development, automate routine work, and enhance code quality.
Requirements
- Minimum 5 years of experience as a Software Engineer, with a strong focus on Python.
- Deep knowledge of pytest, including fixtures, session-scoped testing, timeouts, and black box functional test design for CLI tools.
- Advanced experience with Docker: writing reproducible Dockerfiles, managing user contexts, and securing workspaces.
- Expertise in Linux and Bash scripting, including debugging within containers.
- Familiarity with modern Python tooling (uv, pyproject.toml, packaging).
- Ability to read and understand code in C, C++, Rust, or Go with the help of LLMs.
- Hands-on experience using LLMs (Claude Code, Roo Code, Cursor) to speed up development and generate tests.
- English proficiency at B2 level or higher.
Preferred qualifications
- Background with agent evaluation platforms and MCP CLI.
Key tools & technologies
Python (pytest, uv, Pillow), Docker, Bash, Git Submodules, C/C++/Rust/Go (for code reading), Dagger, GitHub Codespaces, LLMs (Claude Code, Roo Code, Cursor), coverage.py, gcov, kcov.
Benefits & work arrangement
- Freelance, project-based contract through Mindrift (powered by Toloka AI).
- Fully remote position with flexible scheduling. Work 20-30 hours per week and set your own hours.
- Compensation varies by project and experience, with potential earnings up to $50 per hour for this engagement.

