Senior Software Engineer - Remote Freelance

Mindrift; Poland; Remote; PLN 146,553 - 209,361; Full time

Job summary

Mindrift is building a dataset to evaluate AI coding agents by creating challenging tasks and evaluation criteria within realistic simulated environments. You will design prompts, define what counts as solved, and ensure tests accommodate multiple valid approaches while remaining robust.

This role requires 5+ years in software development, strong Python (FastAPI) and JS/TS (React) skills, Docker, Postgres, Kafka and Redis experience, plus experience writing functional and integration tests and

Qualifications

• 5+ years of software development experience required.
• Strong experience with Python (FastAPI) and JavaScript/TypeScript (React).
• Experience writing functional and integration tests.
• English proficiency at least B2+. Keep CV in English.

Responsibilities

• Build realistic developer environments and a believable development history.
• Design tasks from intermediate states of environments and define success criteria.
• Write tests that accept multiple valid solutions while rejecting incorrect ones.
• Iterate on tasks and tests based on QA feedback to ensure fairness and robustness.

Skills

5+ years in software development

Python (FastAPI)

JavaScript/TypeScript (React)

Testing (functional, integration)

Tools

Docker

PostgreSQL

Kafka

Redis

Job description

Please submit your CV in English and indicate your level of English proficiency.

What this opportunity involves

We're building a dataset to evaluate AI coding agents - how well a model handles real-world developer tasks.

You’ll create challenging tasks and evaluation criteria within realistic simulated environments:

• Build realistic developer environments - a virtual company with codebase, infrastructure, and context (tickets, docs, conversations) that forms a believable development history
• Design tasks from intermediate states of these environments - craft the prompt, define what "solved" means, and ensure the task is solvable by an AI agent
• Write tests that verify agent solutions - accept all valid approaches and reject incorrect ones, neither too strict nor too lenient
• Iterate on tasks and tests based on QA feedback - review agent solutions, analyze failures, and refine until the evaluation is fair and robust

What this is NOT

• Not data labeling
• Not prompt engineering
• Not writing code from scratch - the agent writes most of the code; you guide and evaluate

What we look for

• 5+ years in software development
• Core stack: Python (FastAPI), JavaScript/TypeScript (React), Docker, Postgres, Kafka, Redis
• Experience writing tests (functional, integration)
• English proficiency - B2+

Why this is hard

Frontier models are already good at coding. Creating a task that genuinely challenges the best models is non-trivial. You need to deeply understand where models fail and what scenarios reveal the difference between a good and a bad solution. Tasks have many valid solutions - writing tests that accept all correct solutions and reject incorrect ones is harder than it sounds.

How it works

Apply -> Pass qualification(s) -> Join a project -> Complete tasks -> Get paid

Effort estimate

Tasks for this project are estimated to take 20 hours to complete, depending on complexity. This is an estimate and not a schedule requirement; you choose when and how to work. Tasks must be submitted by the deadline and meet the listed acceptance criteria to be accepted.

Compensation

Up to $40/hr equivalent, depending on level and pace. Tasks are estimated at ~20 hours each; you set your own schedule.