Senior ML Engineer - Email Security (remote work)
CloudLinux2 days ago
Remote, Spain +11 moreSenior
Responsibilities
- Train, evaluate, and release spam-detection models by building corpora, selecting thresholds, analyzing precision and recall, and deciding whether to ship or retrain.
- Build the production email-security engine in Go, including the inference service, mail-filter integration, tokenizer, and streaming message parser.
- Improve detection quality end to end by addressing customer-reported phishing, corpus issues, rules, and retraining decisions while balancing false positives and detection rates.
- Maintain corpus tooling and training infrastructure on shared servers and GPU resources.
- Review and approve classifier, rule, and model changes.
- Answer partner engineers’ questions about model scoring and write specifications, handbooks, and post-mortems.
Requirements
- At least 5 years of experience shipping detection or classification systems where false positives had meaningful costs, such as anti-spam, anti-phishing, anti-malware, fraud, or abuse systems.
- Experience taking at least one ML classifier to production, including corpus construction, threshold selection, and error analysis.
- Hands-on transformer training in PyTorch, including tokenizers, masked-language pre-training, fine-tuning, ONNX export, and CPU inference measurement.
- Experience using Linux, shell, and Python on shared servers and a shared GPU.
- Daily use of AI coding agents and tools.
- Upper-Intermediate (B2) English or higher with strong written communication for technical documentation, specifications, and code reviews.
- Experience with email internals, embedded models, Go or Rust systems programming, rspamd or SpamAssassin, large corpora, constrained-hardware models, LLM-based annotation tools, or hosting panels is a strong plus.
Benefits
- Fully remote work from anywhere worldwide with flexible working hours.
- Professional development opportunities and an education budget.
- 24 paid vacation days, 10 national holidays, and unlimited sick leave.
- Private medical insurance compensation.
- Co-working and gym or sports reimbursement.
- Opportunity to receive a reward for an innovative idea that the company can patent.
About CloudLinux
CloudLinux builds a commercially supported Linux operating system and server-hardening tools for hosting providers and data centers running multi-tenant environments. It sells subscriptions and support that improve server stability, resource isolation, and security for shared hosting workloads, along with related maintenance and patching services. Founded in 2009 and headquartered in Estero, Florida, the company is privately held.