Code Data Annotation Quality Specialist

Mistral; Greater London; On-site; GBP 35,000 - 52,000; Full time

Benefits offered by this job

Healthcare coverage

Parental leave

Relocation support

Wellness programs

Meal and transportation allowances

Job summary

Mistral is seeking a Code Data Annotation Quality Specialist to join the Human Data Annotation team. You will review and improve the quality of code annotations and help maintain the internal tooling used by annotators.

You will collaborate with engineers and program managers to refine guidelines, build dashboards and automation, and ensure data used to train AI models meets the highest standards. Ideal candidates bring a CS/engineering background or 2–5 years in related roles, and comfort with

Qualifications

• Degree or 2–5 years in software engineering, technical support, or tool development.
• Hands‑on experience using code agents in development workflows.
• Proficiency in Python or JavaScript and ability to read multiple languages' code.
• Strong rubric‑driven judgment with eye for edge cases and gaps.
• Professional English writing and reading skills.

Responsibilities

• Generate and validate high‑quality data annotations based on guidelines and feedback.
• Identify edge cases and improve guidelines for annotation operations.
• Produce annotations to model the quality bar.
• Build and maintain internal tools to streamline annotator workflows.
• Troubleshoot environment and tooling issues with IT and engineering.
• Collaborate with stakeholders to refine data production processes.

Skills

Python

JavaScript

Code reasoning

English writing

Attention to detail

Education

Bachelor's degree in computer science, engineering, or related field

Tools

Git

Unix shell

Automation tooling

Job description

About Mistral

Mistral provides full‑stack AI solutions: from frontier models to developer tools, applications, and compute. We partner with enterprises tackling the hardest problems—across high‑stakes industries like finance, manufacturing, defense, healthcare, and the public sector—co‑creating customized AI systems that they can run on their terms.

We are a dynamic, collaborative team passionate about AI and its potential to transform society. Our diverse workforce thrives in competitive environments and is committed to driving innovation. Our teams are distributed between Europe, North America, Asia and the Middle East. We are creative, low‑ego and team‑spirited.

The Role

As a Code Data Annotation Quality Specialist on the Human Data Annotation team, you will play a dual role in ensuring the quality of code annotations and maintaining the tools that support annotators. This role exists to uphold the highest standards for data used in training and evaluating AI models, while also improving the workflows and tools that enable efficient annotation. You will spend most of your time reviewing and auditing annotations against rubrics, with the remainder focused on building, maintaining, and troubleshooting internal tooling. Your collaboration with annotators, technical program managers, and engineers will help refine the guidelines and processes that shape how our data is produced.

What You Will Do

• Generate and validate high‑quality data annotations based on guidelines and continuous feedback.
• Surface systemic issues, edge cases, and gaps in guidelines to annotation operations and technical stakeholders.
• Produce annotations yourself to model the quality bar expected of the team.
• Build and maintain internal tools and automation to streamline annotator workflows, such as dashboards, scripts, and utilities.
• Troubleshoot environment, tooling, and version control issues for annotators, liaising with IT and engineering as needed.
• Collaborate with stakeholders to refine guidelines and processes for data production.

What We’re Looking For

• A degree in computer science, engineering, or a related field, or 2 to 5 years of professional experience in software engineering, technical support, or tool development.
• Hands‑on experience using code agents in your development workflow and a genuine interest in their evolution.
• Proficiency in at least one programming language (e.g., Python, JavaScript), with the ability to read and reason about code across multiple languages.
• Ability to apply consistent judgment against a rubric and identify edge cases, ambiguities, or gaps in guidelines.
• Sustained focus and accuracy for detail‑oriented, high‑volume review work.
• Comfort working in a Unix‑like terminal, including shell basics, package managers, environment setup, and version control workflows.
• Ability to troubleshoot local development environment issues across common operating systems.
• Professional proficiency in English, with strong writing and comprehension skills.

What We Offer

We offer a comprehensive benefits package designed to support your well‑being, growth, and work‑life balance. Benefits vary by country and may include healthcare coverage, parental leave, retirement plans, relocation support, wellness programs, meal and transportation allowances, and other location‑specific perks.