Remote Senior ML Engineer - Email Security & Production AI

CloudLinux Inc.; Comunidad de Madrid; Remote; EUR 70,000 - 120,000; Full time

Benefits offered by this job

Fully remote work with flexible hours

Paid 24 days vacation per year

10 national holidays

Unlimited sick leaves

Private medical insurance

Co-working and gym reimbursement

Education budget

Patent-worthy idea rewards

Job summary

CloudLinux Inc. is seeking a Senior Machine Learning Engineer to join the remote-first team. You will drive development, evaluation, and production rollout of Imunify Email security solutions, focusing on spam-detection models, Go-based engine components, and corpus tooling.

The role emphasizes production ML, transformer training in PyTorch, and strong communication skills in English, with remote work globally and a focus on scalable security infrastructure.

Qualifications

• 5+ years shipping detection or classification systems with false-positive cost in mind.
• At least one ML classifier taken to production: corpus construction, threshold selection, error analysis.
• Hands-on transformer training in PyTorch: tokenizers, pre-training, fine-tuning, CPU inference.
• Linux, shell, and Python on shared servers and a shared GPU.
• English at upper-Intermediate (B2) with strong written communication for docs and code reviews.

Responsibilities

• Train, evaluate, and release spam-detection models: build the corpus, pick the threshold, read the precision/recall report, decide ship or retrain.
• Build the production side of the new engine in Go: the inference service, the mail-filter integration, the tokenizer, the streaming message parser.
• Fix detection quality end to end, from customer feedback to rule/corpus fix or retrain.
• Keep the corpus tooling and training infrastructure running.
• Review and approve classifier, rule, and model changes for releases.
• Answer partner engineers who ask why a message scored the way it did.
• Write specs, handbooks, and post-mortems.

Skills

Spam detection experience

Production ML model

Transformer training PyTorch

Linux and Python

English (B2) written

AI tooling

Tools

Go/Rust for systems

rspamd internals

Job description

CloudLinux Inc. is seeking a Senior Machine Learning Engineer to join the remote-first team. You will drive development, evaluation, and production rollout of Imunify Email security solutions, focusing on spam-detection models, Go-based engine components, and corpus tooling.

The role emphasizes production ML, transformer training in PyTorch, and strong communication skills in English, with remote work globally and a focus on scalable security infrastructure.