Sr. Backend Engineer, API
Xai is hiring for the position of Sr. Backend Engineer, API in London, United Kingdom. It is listed as a full-time, senior position.
DGJ summary of this job
Our own short read of this listing, built only from the facts it gives. The employer’s original text follows further down.
Xai is hiring for the position of Sr. Backend Engineer, API in London, United Kingdom. It is listed as a full-time, senior position.
Reading the advert, the employer asks for 5+ years of experience.
Skills and tools named in the text include Rust, C++, PostgreSQL, MongoDB, Kubernetes, Docker, REST and LLM.
The listing gives the pay as £107,000 - £262,000 GBP.
The advert does not mention visa sponsorship. If you would move to United Kingdom for this job, check the official work permit route first (DGJ Insight lists it where we have it).
Dev Global Jobs found this job on Arbeitnow on Nov 14, 2026.
- Employer
- Xai
- Location
- London, United Kingdom
- Job type
- Full-time
- Level (from the title)
- senior
- Pay
- £107,000 - £262,000 GBP
- Experience asked
- 5+ years
- Found
- Nov 14, 2026 on Arbeitnow
- Employer text
- 443 words, about 2 min to read
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- Compare your own experience with the 5+ years the advert asks for, and show it clearly near the top of your CV.
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DGJ Insight
Our own data about this role and place, from official statistics and our live job index.
This job's listed pay is 297% above the benchmark.
Source: OECD Average annual wages, 2025
UN living-cost index for United Kingdom (ICSC post adjustment 76.6), as of 1 Nov 2026.
Source: ICSC post adjustment classifications (icsc.un.org)
- Skilled Worker visa: Job offer from a licensed sponsor at the required skill and salary level; English requirement
- Health and Care Worker visa: Eligible health and social care roles with a licensed sponsor
- Global Talent visa: Endorsement as a leader or potential leader in a listed field
Official routes: UK Visas and Immigration (GOV.UK)
About the role
Full text from the employer, as published on Arbeitnow, arranged into sections. Nothing added or removed.
SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars.
SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next.
SR. BACKEND ENGINEER, API
We are looking for Backend Engineers to help build and operate highly scalable, reliable production infrastructure. Most of our backend infrastructure is written in Rust. Experience with a compiled language such as Rust, C++, or Go is highly beneficial.
01RESPONSIBILITIES
- Build and maintain the unified inference stack as the single surface area for all inference needs across the company
- Own and evolve the platform services that power Chat API, Imagine API, Voice API, Grok Build, and Grok Bot
- Design, build, and maintain Chat API features including batch API, collections API, files API, and related capabilities
- Implement and operate chat moderation and abuse protection systems across the API and grok.com
- Build and maintain the company-wide logging system for all request types, including enforcement of Zero Data Retention (ZDR) policies
- Manage multi-region inference cluster (IC) deployments, data aggregation, data replication, and the distributed authentication system
- Participate in follow-the-sun on-call coverage (UK → Japan → US) to ensure continuous reliability of the inference platform
02BASIC QUALIFICATIONS
- 5+ years of experience in designing, implementing, and maintaining reliable and horizontally scalable distributed systems
- Experience with Rust or C++
03PREFERRED SKILLS AND EXPERIENCE
- Experience in operating databases such as PostgreSQL, Clickhouse, and MongoDB
- Knowledge of service observability and reliability best practices
- 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)
04COMPENSATION AND BENEFITS
£107,000 - £262,000 GBP
Base salary is just one part of our total rewards package at SpaceXSI, which also includes equity, comprehensive healthcare and dental coverage, cash plan, income protection, life insurance, and various other discounts and perks.
SpaceXSI is an equal opportunity employer. For details on data processing, view our Recruitment Privacy Notice.
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