Staff Engineer — Performance, Reliability & AI Automation

Factorial HR; Madrid; Presencial; EUR 90.000 - 130.000; Jornada completa

Descripción de la vacante

Factorial HR is seeking a Staff Software Engineer to join the DX and Performance team in Madrid, focusing on performance, reliability, observability, and AI-assisted workflows. You will shape how Factorial defines, measures, and improves system health and scalability across product and infrastructure.

You’ll contribute hands-on, provide technical leadership, and help teams adopt stronger performance practices at scale in a multicultural, English-speaking environment.

Formación

• Experience improving performance, scalability, and reliability in complex software systems.
• Ability to define or operate SLIs, SLOs, and service health frameworks.
• Strong observability practices and tools knowledge (e.g., Datadog).
• Experience diagnosing bottlenecks across application, database, and distributed layers.
• Experience building load testing and performance validation workflows.
• Experience with cloud-based production systems and cross-team collaboration.

Responsabilidades

• Define and evolve SLIs/SLOs for critical product journeys.
• Improve observability, dashboards, and service health visibility.
• Investigate bottlenecks across application, database, and system layers.
• Drive latency, throughput, scalability, and reliability improvements.
• Build structured load testing workflows for critical paths.
• Partner with product and infrastructure teams on performance priorities.
• Design AI-assisted workflows for metric interpretation and incident analysis.
• Help teams adopt stronger practices around performance at scale.

Conocimientos

Performance engineering

Reliability

Observability

Load testing

AI-assisted workflows

Cross-team communication

Herramientas

Datadog

GraphQL

Ruby on Rails

MySQL

ClickHouse

Kafka

Descripción del empleo

Hello!

Would you love to improve the way companies take care of their people, their most valuable asset?

We are looking for a Staff Software Engineer to join our DX and Performance team at Factorial, with a strong focus on performance, reliability, observability, load testing, and AI-assisted engineering workflows.

DX and Performance Team

The team’s primary goal is to increase Factorial’s quality, performance, and scalability by continuously improving the way we build our product. We focus on strengthening our tools, maintaining foundational elements, and promoting best practices in close collaboration with the rest of the engineering organization.

Our mission is to equip product builders with robust, AI-enabled tools and practices to deliver with quality, confidence, and efficiency. We work across teams to improve software patterns, remove obstacles, complete unfinished migrations, reduce tech debt, and raise the overall engineering bar across the company.

Within this context, performance and reliability are an increasingly important area of focus. As Factorial continues to scale, we want to strengthen how we define service health, measure system behavior, standardize observability, validate systems under load, and apply modern AI workflows to help engineers interpret signals and act faster.

The role

As a Staff Engineer at Factorial, you’ll be part of a team of 200+ Engineers. We look for people who are curious, proactive, technically strong, and effective communicators. People who enjoy solving complex technical problems, raising standards across teams, and building systems that help the whole organization perform at a higher level.

In this role, you will help shape how Factorial defines, measures, and improves performance and service health across the engineering organization. You will work closely with product teams and infrastructure teams to improve observability, load validation, performance visibility, and the engineering practices around these topics.

You will partner with senior engineering leaders across product, infrastructure, and DX to raise the company-wide standard for performance and reliability.

This is a cross-cutting staff role with broad impact. You will contribute through hands-on technical work, technical leadership, and by helping teams adopt stronger practices around SLOs, observability, performance optimization, and AI-assisted analysis workflows.

You’ll work in a multicultural, English-speaking environment where your technical depth, systems thinking, and problem-solving skills will directly contribute to our mission of improving business management processes for companies worldwide.

Factorial serves 15,000+ active customers and 1M+ active users across business-critical workflows. Our current environment includes:

• a large Ruby on Rails backend with GraphQL APIs
• TypeScript frontend applications
• complex CI/CD workflows
• MySQL with replicas for OLTP workloads
• ClickHouse for analytical workloads
• Kafka for event-driven and asynchronous processing
• a multi-region cloud architecture
• meaningful TPS, IOPS, concurrency, and sustained operational load

Don’t let unfamiliarity with every part of this stack hold you back. If you have worked in complex systems, know how to reason about performance and reliability at scale, and are excited to help teams build better software with better signals, we want to talk to you.

What you will work on

• Defining and evolving SLIs and SLOs for critical product journeys
• Improving and standardizing observability, dashboards, and service health visibility across teams
• Investigating bottlenecks and regressions across application, database, asynchronous, and system layers
• Driving improvements in latency, throughput, scalability, and reliability
• Building more structured load testing workflows for critical paths
• Helping teams validate system behavior under realistic traffic, concurrency, and tenant-scale conditions
• Analyzing capacity, saturation, and behavior under peak load and growth scenarios
• Defining practices and tooling to help prevent performance regressions before production
• Working closely with product and infrastructure teams to align on performance priorities and system behavior under load
• Designing AI-assisted workflows to support metric and alert interpretation, anomaly analysis, incident investigation, performance insights generation and more

We are looking for profiles that have

• Strong hands-on experience improving performance, scalability, and reliability in complex software systems
• Experience defining or operating SLIs, SLOs, and service health frameworks
• Strong knowledge of observability practices and tools such as Datadog
• Experience investigating production bottlenecks across application, database, and distributed system layers
• Experience building or improving load testing, benchmarking, or performance validation workflows
• Experience diagnosing tail latency, throughput issues, and performance variability in production
• Broad experience working with cloud-based production systems
• Strong communication skills, including technical writing and cross-team alignment
• A proactive mindset and strong ownership mentality

Ideally, you also bring

• Significant experience building and operating production systems at scale
• Experience working in large-scale environments with meaningful traffic and operational complexity
• Experience with Ruby on Rails, MySQL, Kafka, GraphQL, ClickHouse, or equivalent technologies
• Previous experience in Performance Engineering or Reliability Engineering
• Interest in modern AI tools and practical use of agentic workflows in engineering

How We Work (Barcelona)

At Factorial, we believe the best products are built when people come together, in person, to collaborate, challenge ideas, and move fast. That’s why our Engineering teams follow an office-first, flexible approach.

We work on‑site several days a week, using that time to connect, align, and innovate as a team. At the same time, we support remote work when it makes sense for focus, flexibility, or personal needs.

This balance helps us stay agile, creative, and closely connected, while giving everyone the space to do their best work.

About us

At Factorial, we’re building the leading business management software for companies of all sizes. Our platform centralizes key workflows across HR, finance, and operations, freeing teams from manual processes so they can focus on what really matters: leading, growing, and taking care of their people. With over 1,200 employees across 7 markets, we serve 700,000+ users and are one of Europe’s fastest-growing SaaS companies, backed by top-tier investors and proudly headquartered in Barcelona. We believe in bold goals, radical ownership, and inclusive collaboration. If you're excited to shape the future of business management technology, we’d love to meet you.

Our Values

• We own it : We take responsibility for every project. We make decisions, not excuses.
• We learn and teach : We're dedicated to learning something new every day and, above all, share it.
• We partner : Every decision is a team decision. We trust each other.
• We grow fast : We act fast. We think that the worst mistake is not learning from them.
• We believe in diverse talent : We welcome applicants from all backgrounds and strongly encourage people of diverse experiences and identities to apply.
• We believe in inclusion : We are committed to equal opportunities and actively promote workplace inclusion of people with disabilities. If you would like to learn more about our inclusive recruitment processes, you are welcome to indicate so optionally and we will share additional information with you.

Wanna learn more about us? Check our website!

Perks of being part of our team

• High growth, multicultural and friendly environment
• Alan as private health insurance
• Healthy life with Wellhub (Gyms, pools, outdoor classes)
• Save expenses with Cobee
• Language classes
• Breakfast in the office and organic fruit
• Nora discounts
• Free caffeine and theine
• Pet Friendly