Location: Remote (India or UK preferred)
Type: Full-Time | Permanent
Tech: Python, PyTorch, scikit-learn, MLflow/W&B, DataFrames, SQL, AWS (SageMaker/Bedrock)
Comp: Competitive salary + meaningful equity

Why This Role Exists

PubX builds publisher-first agentic advertising infrastructure — AI that makes real-time, revenue-critical pricing decisions for digital publishers. Our dynamic floor pricing engine uses machine learning to optimize every programmatic ad auction individually, generating measurable revenue uplift for publishers. We’re ranked #5 globally in Prebid Analytics Adapter Rankings, and growing.

The problem we’re solving

Digital publishers leave significant revenue on the table because ad pricing is still largely static or rule-based. Every ad impression is unique, but most pricing systems treat them the same. PubX’s AI analyzes bid-stream data and historical patterns to set optimal price floors per auction, in real-time. As we expand into agentic AI systems, we’re building the next generation of autonomous advertising infrastructure.

About us

We’re a ~25-person, fully remote team founded in 2020 by Andrew Mole (CEO) and Alex Rosen (CTO), who previously built Platform360 — a machine-learning powered DSP — giving them a decade of deep AdTech experience. We’re seed-funded, profitable in our core product, and growing our engineering team with a strong presence in India and UK leadership. Our investors include Concept Ventures, Haatch, and Force Over Mass Capital.

The Role

As a Senior Data Engineer, you’ll own the data foundations behind our agentic AI products. This means building and operating high-throughput batch and streaming pipelines, scalable storage and modeling layers, and reliable datasets that power real-time decisioning, analytics, and ML workflows. You’ll work across event ingestion, enrichment, aggregation, and serving — dealing with the kind of volume and latency constraints that make AdTech data engineering genuinely interesting.

You’ll collaborate closely with product, data science, and operations in a distributed team, contributing to both day-to-day delivery and longer-term architectural decisions. This role has a clear path to evolve into a Tech Lead position for one of our product teams.

What You’ll Work On

• Design, train, evaluate, and deploy ML models that power real-time pricing decisions across billions of ad auction events
• Build and maintain production ML pipelines end-to-end: feature engineering, training, validation, deployment, monitoring, and retraining
• Develop and operate MLOps infrastructure (experiment tracking, model registry, A/B testing frameworks, automated retraining) on AWS using infrastructure-as-code
• Integrate LLM and agentic AI components into product workflows, including prompt engineering, orchestration, evaluation, and feedback loops
• Build feature pipelines and serving layers that operate at low latency and high throughput, working closely with data and backend engineers
• Own model observability and reliability: drift detection, performance monitoring, alerting, SLAs, and post-incident reviews
• Contribute to backend services and data pipelines where needed to close the gap between model development and production delivery

What We’re Looking For

We’re looking for an experienced engineer who has worked on production systems and enjoys solving practical problems with AI.

You’ve likely have:

• Strong ML engineering fundamentals: model development, feature engineering, evaluation methodology, and a solid understanding of when (and when not) to apply ML
• Hands-on experience deploying and operating ML models in production, including managing model lifecycle, versioning, A/B testing, and monitoring for drift and degradation
• Experience building MLOps tooling and infrastructure (e.g., MLflow, W&B, SageMaker Pipelines, Kubeflow, or similar) to support reproducible, automated workflows
• Solid Python skills with comfort across the ML ecosystem (PyTorch/TensorFlow, scikit-learn, pandas, Spark) and the ability to write production-quality code — not just notebooks
• Experience integrating LLM/agentic AI components into production systems, including evaluation, grounding, and feedback capture
• Working knowledge of backend engineering: APIs, async processing, and containerised deployments — enough to ship models as reliable services

You tend to:

• Make pragmatic decisions balancing speed, quality, cost, and risk trade-offs.
• Communicate technical ideas well in writing and conversation to both technical and non-technical audiences.
• Write clean, well-tested code with thoughtful abstractions that’s easy to extend and operate.
• Learn quickly when things are unfamiliar by prototyping, then hardening and documenting what you ship.

Bonus (not required):

• Experience with AdTech or other high volume real-time systems

Who This Role Will Suit

This role suits engineers who like a mix of autonomy and collaboration, and who are comfortable working in an environment that’s still evolving.

We’re a distributed team with a growing engineering presence in India, so comfort with async collaboration and clear written communication is important.

We use agentic coding tools heavily (e.g., Cursor and Claude Code) to plan, scaffold, refactor, and debug production code, while maintaining strong engineering judgment and ownership of outcomes.

Interview Process

Our process is designed to be practical and respectful.

1. CV & Profile Review – Relevant experience and background
2. Initial Chat (30 mins) – Motivation and role fit
3. Technical Interview (60 mins) – Architecture, design choices, and real scenarios
4. Practical Exercise + Discussion (60 mins) – A small task related to the role

What We Offer

• Competitive salary with meaningful equity
• Fully remote, async-friendly working
• Supportive, low-ego engineering culture
• Budget for learning and professional development

If you’re interested in building and improving real systems in a growing product company, we’d love to hear from you.