Backend Engineer

Pantera Capital; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

A technology-driven company in Greater London seeks a skilled Backend Engineer proficient in Rust or C++. You will work on highly scalable production infrastructure and contribute to robust distributed systems. A successful candidate should also have experience with service observability and various databases. Benefits include a competitive salary, equity, and comprehensive medical coverage.

Benefits

Equity

Medical coverage

Pension plan

Disability insurance

Qualifications

• Expert knowledge of Rust or C++.
• Experience in designing and maintaining reliable distributed systems.
• Knowledge of service observability best practices.

Responsibilities

• Work on scalable production systems for grok.com and API.
• Design and implement reliable infrastructure solutions.

Skills

Rust

C++

Service observability

Database management

Docker

Kubernetes

Python

TypeScript

gRPC

Tools

PostgreSQL

Clickhouse

MongoDB

Job description

About xAI

xAI’s mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. Our team is small, highly motivated, and focused on engineering excellence. This organization is for individuals who appreciate challenging themselves and thrive on curiosity. We operate with a flat organizational structure. All employees are expected to be hands‑on and to contribute directly to the company’s mission. Leadership is given to those who show initiative and consistently deliver excellence. Work ethic and strong prioritization skills are important. All engineers are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates.

About the team

In this role you will work on xAI's production systems that power grok.com and the API. The actual team matching will happen at the offer stage.

About the role

As an ideal candidate you have a good understanding of how highly scalable and reliable production infrastructure is built. You strive for perfection and listen carefully to your users in order to solve any pain points they might experience. Most of our backend infrastructure is written in Rust. So familiarity with a compiled language such as C++, Rust, or Go is highly beneficial.

• Expert knowledge of either Rust or C++
• Experience in designing, implementing, and maintaining reliable and horizontally scalable distributed systems
• Knowledge of service observability and reliability best practices
• Experience in operating commonly used databases such as PostgreSQL, Clickhouse, and MongoDB

Additionally, any of the below points will help a candidate stand out:

• Expert knowledge of Python
• Experience with Docker, Kubernetes, and containerized applications
• Expert knowledge of TypeScript
• Expert knowledge of gRPC (unary, response streaming, bi-directional streaming, REST mapping)
• Hands‑on experience with LLM APIs, embeddings, or RAG patterns
• Track record of delivering user‑facing software at scale

Interview process

After submitting your application, the team reviews your statement of exceptional work and CV. If your application passes this stage, you will be invited to a 15 minute interview ("phone interview") during which a member of our team will ask some basic technical questions. If you clear the initial phone interview, you will enter the main process, which consists of at least two technical interviews:

1. Coding interview in Rust or C++.
2. Distributed systems design interview.

Benefits

Base salary is just one part of our total rewards package at xAI, which also includes equity, comprehensive medical, vision, and dental coverage, access to a pension plan, short & long-term disability insurance, life insurance, and various other discounts and perks.

xAI is an equal opportunity employer.

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