Senior Machine Learning Engineer

Cloudflare; Greater London; Hybrid; GBP 110,000 - 140,000; Full time

Job summary

Cloudflare in London is seeking an ML engineer to define how machine learning models run across Cloudflare’s global network. You’ll collaborate with systems engineers, product teams, hardware partners, and AI/ML engineers to deploy models with low latency, strong reliability, and efficient resource use in production.

You’ll focus on benchmarking, evaluation, and tooling to help Cloudflare and its customers ship AI applications at internet scale.

Qualifications

• Experience building, optimizing, and operating ML models in production.
• Proficiency with Python and ML frameworks (PyTorch, TensorFlow, JAX).
• Hands-on inference optimization for large-scale models (quantization, batching, caching).
• Experience with model serving runtimes (TensorRT-LLM, ONNX Runtime, Triton).
• Familiarity with LLMs, speech/vision models, embeddings, multimodal modeling.

Responsibilities

• Develop, optimize, and productionize ML models for Cloudflare’s serverless inference platform.
• Build benchmarking/evaluation frameworks for latency, throughput, and cost efficiency across model families.
• Improve inference performance via quantization, batching, caching, and runtime tuning.

Skills

Python

PyTorch

TensorFlow

JAX

LLMs

Inference optimization

Model deployment

Performance tuning

Mentoring

Distributed systems

Tools

SGLang

vLLM

TensorRT-LLM

ONNX Runtime

Triton

llama.cpp

Job description

About Us

At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. Cloudflare was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company.

At Cloudflare, we’re not looking for people who wait for a polished roadmap; we’re looking for the builders who see the cracks in the Internet that everyone else has simply learned to live with. We value candidates who have the instinct to spot a \"normalized\" problem and the AI-native curiosity to create a solution using the latest tools. Our culture is built on iteration, leveraging AI to ship faster today to make it better tomorrow, while ensuring that every improvement, no matter how small, is shared across the team to lift everyone up. If you’re the type of person who values curiosity over bureaucracy, and that AI is a partner in solving tough problems to keep the Internet moving forward, you’ll fit right in.

Available Locations

Austin, TX or London, UK (Hybrid)

About The Role

You’ll help define how machine learning models run across Cloudflare’s global network, from frontier open LLMs and real-time voice models to customer‑deployed models served on heterogeneous GPUs and next‑generation accelerators. You’ll work with systems engineers, product teams, hardware partners, and AI/ML engineers to bring models into production with low latency, strong reliability, and efficient resource use. This role combines applied ML, inference optimization, evaluation, and production engineering, with a focus on benchmarking models, improving serving performance, validating quality, and building tooling that helps Cloudflare and its customers ship AI applications at Internet scale.

Responsibilities

• Develop, optimize, and productionize machine learning models for Cloudflare’s serverless inference platform, with a focus on performance, reliability, and model quality.
• Build benchmarking and evaluation frameworks to measure latency, throughput, cost efficiency, and model behavior across LLMs, speech, vision, and other model families.
• Improve inference performance through quantization, batching, caching, model compilation, runtime tuning, and accelerator‑aware optimization.
• Partner with systems engineers to integrate models into Cloudflare’s distributed inference infrastructure across a heterogeneous fleet of GPUs and next‑generation accelerators.
• Drive improvements to model deployment workflows, including validation, rollout safety, observability, regression testing, and operational readiness.
• Collaborate with product and engineering teams to translate customer requirements into scalable ML capabilities for Workers AI.
• Mentor engineers, contribute to technical direction, and raise the quality bar for production ML engineering practices across the team.

Desirable Skills, Knowledge, And Experience

• Experience building, optimizing, and operating machine learning models in production environments.
• Strong proficiency with Python and modern ML frameworks such as PyTorch, TensorFlow, JAX, or equivalent.
• Hands‑on experience with inference optimization techniques for large‑scale models, including quantization, batching, caching, compilation, and serving runtime tuning.
• Experience with large‑scale inference serving frameworks or runtimes such as SGLang, vLLM, TensorRT‑LLM, ONNX Runtime, Triton, llama.cpp, or similar.
• Familiarity with LLMs, speech models, vision models, embeddings, multimodal models, retrieval‑augmented generation, or other modern deep learning architectures.
• Experience optimizing models for GPUs or specialized accelerators.
• Strong understanding of production ML concerns, including evaluation, monitoring, model regressions, rollout safety, and reliability.
• Ability to work across ML and systems boundaries, including familiarity with distributed systems, networking, or serverless platforms.
• Track record of leading complex technical projects and mentoring other engineers.

Bonus Points

• Experience contributing to open source ML tooling, model serving frameworks, or inference runtimes.

What Makes Cloudflare Special?

We’re not just a highly ambitious, large‑scale technology company. We’re a highly ambitious, large‑scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.

Project Galileo

Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers—at no cost.

Athenian Project

In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we've provided services to more than 425 local government election websites in 33 states.

1.1.1.1

We released 1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy‑centric public DNS resolver. This is available publicly for everyone to use—it is the first consumer‑focused service Cloudflare has ever released. Here’s the deal— we don’t store client IP addresses never, ever. We will continue to abide by our privacy commitment and ensure that no user data is sold to advertisers or used to target consumers.

Please note that applicants who progress to the offer stage of the interview process may be asked to attend an in‑person interview within one of the Cloudflare Offices or Cloudflare Hubs. More details about this will be available at that stage of the interview process.

This position may require access to information protected under U.S. export control laws, including the U.S. Export Administration Regulations. Please note that any offer of employment may be conditioned on your authorization to receive software or technology controlled under these U.S. export laws without sponsorship for an export license.

Cloudflare is proud to be an equal opportunity employer. We are committed to providing equal employment opportunity for all people and place great value in both diversity and inclusiveness. All qualified applicants will be considered for employment without regard to their, or any other person's, perceived or actual race, color, religion, sex, gender, gender identity, gender expression, sexual orientation, national origin, ancestry, citizenship, age, physical or mental disability, medical condition, family care status, or any other basis protected by law. We are an AA/Veterans/Disabled Employer.

Cloudflare provides reasonable accommodations to qualified individuals with disabilities. Please tell us if you require a reasonable accommodation to apply for a job. Examples of reasonable accommodations include, but are not limited to, changing the application process, providing documents in an alternate format, using a sign language interpreter, or using specialized equipment. If you require a reasonable accommodation to apply for a job, please contact us via e‑mail at [e-mail] or via mail at 101 Townsend St. San Francisco, CA 94107.