xAI Logo

xAI

Backend Engineer - API

Reposted 2 Months Ago
Be an Early Applicant
In-Office
London, Greater London, England, GBR
Mid level
In-Office
London, Greater London, England, GBR
Mid level
Develop and maintain the xAI API for high-throughput inference, managing model serving infrastructure, request routing, and scaling.
The summary above was generated by AI

SpaceXAI’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 employees are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates.

ABOUT THE ROLE:

As an ideal candidate you have a good understanding of how highly scalable and reliable production infrastructure is built. Most of our backend infrastructure is written in Rust. So familiarity with a compiled language such as C++, Rust, or Go is highly beneficial.

RESPONSIBILITIES:
  • Build the SpaceXAI API that serves our models to developers worldwide
  • Own the end-to-end system responsible for high-throughput inference, handling billions of tokens per minute with low latency and high availability, including model serving infrastructure, request routing, SDK development, rate limiting, observability, and efficient scaling
BASIC QUALIFICATIONS:
  • 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
PREFERRED SKILLS AND EXPERIENCE:
  • Experience with LLM inference engines and serving frameworks (e.g., SGLang, TensorRT, vLLM)
  • Experience designing or building with agent SDKs and agent orchestration frameworks
  • Experience with Docker, Kubernetes, and containerized applications
  • Expert knowledge of gRPC (unary, response streaming, bi-directional streaming, REST mapping)
COMPENSATION AND BENEFITS:

£107,000 - £262,000 GBP

Base salary is just one part of our total rewards package at SpaceXAI, which also includes equity, comprehensive healthcare and dental coverage, cash plan, income protection, life insurance, and various other discounts and perks.

SpaceXAI is an equal opportunity employer. For details on data processing, view our Recruitment Privacy Notice.

xAI London, England Office

20 Air Street, London, London, United Kingdom

Similar Jobs

14 Minutes Ago
Hybrid
London, Greater London, England, GBR
Entry level
Entry level
Fintech • Mobile • Payments • Software • Financial Services
Build and maintain backend services for Wise’s Contacts team, powering recipient discovery, management, and customer interactions at large scale. Responsibilities include designing distributed systems, RESTful APIs, database schemas, and query optimization; deploying reliable services; writing testable code; and collaborating with product, design, and analytics teams using an agile, customer-focused approach.
Top Skills: Backend-For-Frontends (Bffs)JavaNon-Relational DatabasesRelational DatabasesRestful ApisSpring Boot
53 Minutes Ago
Hybrid
London, England, GBR
Entry level
Entry level
Fintech • Professional Services • Consulting • Energy • Financial Services • Cybersecurity • Generative AI
Lead and support strategic and technology-enabled transformation programmes for commercial and specialty insurers. Responsibilities include current-state assessments, target operating model design, business and functional requirements, workstream management, stakeholder engagement, governance, testing, UAT, platform optimisation, and benefits realisation across underwriting, claims, and policy administration.
Top Skills: Bcs Business AnalysisGuidewirePmpPrince2SafeScrumSequel
59 Minutes Ago
Hybrid
London, Greater London, England, GBR
Senior level
Senior level
eCommerce • Information Technology • Marketing Tech • Software
Design, build, and operate Akeneo’s Supplier Data Manager at enterprise scale. Develop reliable data-processing pipelines for messy supplier catalogues, including deterministic and LLM-powered extraction and classification. Create collaboration and governance workflows, ensure production observability and operational excellence, participate in customer discovery, and collaborate across teams. The role requires strong software engineering fundamentals, architectural thinking, debugging ability, end-to-end ownership, and clear communication.
Top Skills: Claude CodeGCPInfrastructure As CodeLlmsPHPPythonReactTypescript

What you need to know about the London Tech Scene

London isn't just a hub for established businesses; it's also a nursery for innovation. Boasting one of the most recognized fintech ecosystems in Europe, attracting billions in investments each year, London's success has made it a go-to destination for startups looking to make their mark. Top U.K. companies like Hoptin, Moneybox and Marshmallow have already made the city their base — yet fintech is just the beginning. From healthtech to renewable energy to cybersecurity and beyond, the city's startups are breaking new ground across a range of industries.

Sign up now Access later

Create Free Account

Please log in or sign up to report this job.

Create Free Account