Software Engineer, Backend

BlackCube Labs; Greater London; Hybrid; GBP 80,000 - GBP 100,000; Full time

Job summary

A leading AI company in Greater London is seeking a Backend Engineer to develop resilient backend systems and APIs for its products. The ideal candidate will have strong Python skills and experience in backend fundamentals. Responsibilities include designing scalable features, collaborating with cross-functional teams, and tackling complex engineering challenges. The position offers a competitive salary, health insurance, and other benefits, with a focus on team collaboration and innovation.

Benefits

Competitive salary and equity

Health insurance

Transportation allowance

Sport allowance

Meal vouchers

Private pension plan

Generous parental leave policy

Visa sponsorship

Qualifications

• Proficient in Python or other backend languages like JavaScript/TypeScript.
• Strong understanding of APIs, databases, and caching.
• Ability to ship end-to-end features with minimal oversight.

Responsibilities

• Design and develop scalable backend features and APIs.
• Collaborate with cross-functional teams for end-to-end feature delivery.
• Tackle complex engineering challenges.

Skills

Proficiency in Python

Backend fundamentals

Problem-solving abilities

Excellent communication skills

Education

Degree in Computer Science or Software Engineering

Tools

Docker

CI/CD

Kubernetes

Job description

About Mistral

At Mistral AI, we believe in the power of AI to simplify tasks, save time and enhance learning and creativity. Our technology is designed to integrate seamlessly into daily working life.

We democratize AI through high-performance, optimized, open-source and cutting-edge models, products and solutions. Our comprehensive AI platform is designed to meet enterprise needs, whether on-premises or in cloud environments. Our offerings include le Chat, the AI assistant for life and work.

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 France, USA, UK, Germany and Singapore. We are creative, low-ego and team-spirited.

Join us to be part of a pioneering company shaping the future of AI. Together, we can make a meaningful impact. See more about our culture on https://mistral.ai/careers.

Role summary

We are seeking passionate and skilled software engineers to join our team. As a Backend Engineer, you’ll contribute to the development of the core systems powering our three main products, AI Studio, Le Chat & Mistral Code, shaping how users and developers interact with our AI platform at scale. You’ll work on building reliable, high-performance backend systems and APIs that serve millions of users and developers. Your work will directly impact the developer and user experience, making it more engaging, efficient, and intuitive. We welcome engineers at all levels from fresh graduates to senior and staff engineers and who are eager to learn, collaborate and ship impactful products.

What you will do

Depending on your skills and field of expertise, you will be involved in key components of our technology, including:

Backend Development

• Design, develop and maintain scalable, robust backend features and APIs using modern frameworks.
• Ensure high performance and reliability across our distributed systems.
• Contribute to systems powering authentication, billing, AI tooling, observability, connectors, and developer experience.

System Architecture

• Design and implement efficient, secure and scalable architectures that support our fast-growing products.
• Collaborate with infrastructure teams on deployment, monitoring, and performance optimization.

Code Quality

• Write clean, maintainable and well-documented code.
• Participate in code reviews and contribute to technical standards and best practices.

Cross-functional Collaboration

• Work closely with product managers, front-end engineers, designers and data/AI engineers to deliver end-to-end features.
• Partner with teams across AI Studio, Le Chat & Mistral Code to ensure consistent platform-wide experience.

Problem-Solving & Innovation

• Tackle complex engineering challenges, from distributed systems to AI product integration.
• Stay up-to-date with new technologies (e.g., AI/LLM integration, observability, or backend frameworks) and bring them into production when relevant.

About you

• Degree in Computer Science, Software Engineering, or equivalent practical experience.
• Proficiency in Python or another backend language (JavaScript/TypeScript, C#, Golang). Engineers are assessed in their preferred language during a live coding session.
• Strong understanding of backend fundamentals: APIs, databases, caching, messaging systems and distributed architectures.
• Strong problem-solving abilities and attention to detail.
• Ownership mindset capable of shipping end-to-end features with minimal oversight.
• Excellent communication skills and collaborative attitude.
• Team-oriented, low-ego mindset and curiosity for learning.

Ideal experience

• Front-end development (Typescript, React, NextJS...) or full-stack exposure
• Infrastructure management (Docker, CI/CD, Kubernetes, Helm, Terraform...)
• AI/ML engineering
• Observability and monitoring tools (Prometheus, Grafana, Datadog….)
• UX and product-centric mindset.

Hiring Process

• Introduction call - 45 min
• Live-coding interview - 45 min
• System Design interview - 45 min
• Hiring Manager interview - 30 min
• Deep Dive Interview (only for leads & staff engineers) - 60 min
• Culture-fit discussion - 30 min
• Reference checks

Our Culture

• Reason with rigor
• Are you audacious enough?
• Make our customers succeed
• Ship early and accelerate
• Leave your ego aside

Engineering blog

Our first Engineering blog post is live, you can check it out here !

Location & Remote

The position is based in our London office and we encourage going to the office as much as we can (at least 3 days per week) to create bonds and smooth communication. Our remote policy aims to provide flexibility, improve work-life balance and increase productivity. Each manager can decide the amount of days worked remotely based on autonomy and a specific context (e.g. more flexibility can occur during summer). In any case, employees are expected to maintain regular communication with their teams and be available during core working hours.

What we offer

• 💰 Competitive salary and equity (stock-options)
• 🧑⚕️ Health insurance
• 🚴 Transportation allowance
• 🥎 Sport allowance
• 🥕 Meal vouchers
• 💰 Private pension plan
• 🍼 Generous parental leave policy
• 🌎 Visa sponsorship