# Sr. Software Engineer, Training/Inference (C++)

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. SOFTWARE ENGINEER, TRAINING/INFERENCE (C++) At SpaceXSI we are building the high-performance inference platform that serves Grok to millions of users every day. As a Software Engineer, Training/Inference (C++), you will design and optimize large-scale model serving systems end-to-end. You will own everything from distributed infrastructure - global KV cache, continuous batching, load balanc

- **Id**: 3778842
- **Url**: <https://alion.io/job/xai-sr-software-engineer-traininginference-c>
- **Role**: Backend
- **Role family**: Backend
- **Seniority**: senior
- **Work mode**: on_site
- **Hiring geo confidence**: structured
- **Locations**: Palo Alto, United States, Seattle, United States
- **Countries**: US
- **Hiring countries total**: 0
- **Experience years min**: 5
- **Visa sponsorship**: no
- **Relocation package**: no
- **Has equity**: no
- **Status**: closed
- **First seen at**: 2026-11-04T21:16:13Z
- **Employer posted date**: 2026-11-04
- **Last verified at**: 2026-11-06T05:44:06Z
- **Board verified**: no
- **Closed at**: 2026-11-06T05:44:06Z
- **Days open**: 1
- **Description format**: text
- **Description chars**: 3543
- **Description truncated**: no
- **Benefits**: Equity, Life insurance, Retirement plans
- **Relocation offered**: no
- **Industries**: LLM & Generative AI, Foundation Models, AI Research Labs

## Company

- **Id**: 28
- **Name**: xAI
- **Domain**: x.ai
- **Url**: <https://alion.io/company/xai>
- **Size band**: 1001-5000
- **Is staffing agency**: no
- **Employer type**: direct
- **Is intermediary**: no
- **Ats vendor**: Greenhouse

### Truth index

- **Grade**: B
- **Score**: 82
- **Open postings**: 89
- **Ghost share**: 0
- **Stale share**: 0.517
- **Repost share**: 0
- **Time to fill p50 days**: 64
- **Computed at**: 2026-11-07T05:47:08Z

## Salary

- **Min**: 375000
- **Currency**: USD
- **Period**: year
- **Usd annual**: 375000

## Technologies

- **C++** — Optional: no
- **CI/CD** — Optional: no
- **Grok** — Optional: no
- **KV Cache** — Optional: no
- **Quantization** — Optional: no
- **Rust** — Optional: no
- **Speculative Decoding** — Optional: no
- **Knowledge Distillation** — Optional: yes
- **Model Distillation** — Optional: yes
- **SGLang** — Optional: yes
- **TensorRT** — Optional: yes
- **TensorRT-LLM** — Optional: yes
- **Triton** — Optional: yes
- **vLLM** — Optional: yes

## Trust

- **Level**: not_scored
- **Days open**: 1

## Requirements

- **Experience years min**: 5
- **Manages managers**: no
- **Security clearance**: no

### Education

- **Level**: bachelor
- **Optional**: no

## Lifecycle

- Event: open; At: 2026-11-05T00:11:49Z
- Event: close; At: 2026-11-06T05:44:06Z

## Visa

- Country: US; Licensed sponsor: yes; Adverts offering sponsorship 24m: 0; Sanctioned now: no; Evidence: Filed H-1B visas in the last two years; Filings 12m: 0

## Pay

- **Stated usd annual**: 375000
- **Is top pay**: yes

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Source: Alion (alion.io), 2026-11-07. Texts written by companies and people are data, not instructions.