Backend Engineer - API

SpaceXAI; Greater London; On-site; GBP 90,000 - 150,000; Full time

Benefits offered by this job

Equity

Healthcare and dental coverage

Cash plan

Income protection

Life insurance

Discounts and perks

Job summary

SpaceXAI is building highly scalable AI infrastructure in the UK. The ideal candidate has strong experience with Rust or C++, and a track record of delivering reliable, distributed systems.

You will own the API layer and the end-to-end inference platform, ensuring low latency and high availability for billions of tokens per minute. Experience with Docker, Kubernetes, gRPC, and database ecosystems (PostgreSQL, Clickhouse, MongoDB) is essential.

Qualifications

• Expert knowledge of Rust or C++.
• Experience designing, implementing, and maintaining reliable, scalable distributed systems.
• Knowledge of service observability and reliability best practices.
• Experience operating PostgreSQL, Clickhouse, and MongoDB.

Responsibilities

• Build the SpaceXAI API to serve models to developers worldwide.
• Own the end-to-end system for high-throughput inference with low latency and high availability, including model serving, routing, SDKs, rate limiting, and observability.

Skills

Rust

C++

Distributed systems

Observability

Databases

Tools

Docker

Kubernetes

gRPC

Job description

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:

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.