Nowadays, the reliability of software systems is critical. Whether you’re streaming a film, shopping online, or managing your finances via an app, you expect services to work without a hitch. Behind the scenes, ensuring this seamless experience are professionals known as Site Reliability Engineers (SREs). But what is a Site Reliability Engineer exactly? And what skills do they need to keep systems running smoothly?
This blog explores the role, responsibilities, and essential skills of a Site Reliability Engineer, why they are becoming indispensable in modern tech teams and how mthree can help you begin your SRE career.
> What actually is a site reliability engineer?
A Site Reliability Engineer (SRE) is a hybrid role that blends software engineering with IT operations. Originally coined and developed by Google in the early 2000s, the SRE role was created to solve a key problem: how to manage large-scale systems reliably and efficiently.
At its core, a Site Reliability Engineer is responsible for ensuring that applications and systems are scalable, stable, and performant. This means they are deeply involved in automating operational tasks, building robust infrastructure, and implementing systems to detect, monitor and respond to incidents swiftly.
Unlike traditional operations teams, SREs bring a software engineering mindset to solving operational problems. Instead of relying solely on manual processes, they create tools, write code, and develop automation to reduce toil and improve system reliability.
> What do they do day to day?
So, Site Reliability Engineers: what do they do on a day-to-day basis? While the specifics may vary depending on the organisation, the core responsibilities tend to fall into a few key areas:
1. System monitoring and incident response
SREs monitor systems to detect issues before they affect users. They set up alerting systems, dashboards, and logging tools to gain visibility into application health. When incidents do occur, SREs are often the first responders. They investigate root causes, coordinate responses, and implement fixes to prevent recurrence.
2. Automation and tooling
One of the primary goals of an SRE is to reduce manual work. They build automation to handle repetitive tasks such as deployments, scaling, backups, and configuration changes. This allows teams to move faster and more reliably.
3. Infrastructure as code
Site Reliability Engineers often manage infrastructure using code rather than manual configuration. Tools like Terraform, Ansible, and Kubernetes are commonly used to provision and manage resources in a consistent and repeatable way.
4. Capacity planning and performance optimisation
SREs analyse system performance and predict future growth. They help plan for capacity and ensure applications can handle increased load without degradation. Performance tuning and load testing also fall under their remit.
5. Availability and reliability
A key goal of SREs is to improve availability without compromising development speed. They define Service Level Objectives (SLOs) and Service Level Indicators (SLIs) to measure and manage reliability. If a service drops below its SLO, it prompts a review and changes in processes or priorities.
> Site Reliability Engineer skills
To be effective in their role, SREs need a broad and deep technical skill set. They sit at the intersection of software engineering and systems administration, requiring both coding ability and operational awareness.
Here are some of the core site reliability engineer skills:
1. Programming and scripting
SREs need to be proficient in at least one programming language, typically Python, Go, or Java. Scripting skills in Bash or PowerShell are also useful for automating routine tasks.
2. Linux and system administration
A strong understanding of Linux systems is essential, as most cloud-native infrastructure runs on Linux. This includes knowledge of file systems, networking, process management, and security.
3. Cloud platforms
Experience with cloud services such as AWS, Azure, or Google Cloud Platform is crucial. SREs must understand how to deploy and manage services in a cloud-native environment.
4. Monitoring and observability tools
SREs use tools like Prometheus, Grafana, ELK Stack, and Datadog to monitor systems and diagnose issues. Understanding how to collect, visualise, and interpret metrics is key to maintaining reliability.
5. CI/CD and DevOps practices
Site Reliability Engineers are heavily involved in the deployment process. Familiarity with CI/CD pipelines, version control (Git), and tools like Jenkins, GitLab CI, or GitHub Actions is important for supporting rapid and safe software delivery.
6. Incident management and troubleshooting
SREs must be calm under pressure and be able to troubleshoot complex systems quickly. They need to document incidents, run postmortems, and continuously improve processes.
7. Communication and collaboration
Because SREs work across teams, good communication skills are vital. They collaborate with developers, product managers, QA engineers, and support staff to ensure systems meet user needs and business goals.
> Why are Site Reliability Engineers in high demand?
The rise of cloud computing, microservices, and continuous delivery has made system reliability more complex and critical than ever. As a result, the demand for skilled Site Reliability Engineers has surged.
Companies are realising that downtime costs money and erodes user trust. A well-implemented SRE practice can dramatically improve uptime, reduce incident frequency, and enable faster feature delivery. In essence, SREs help balance innovation with stability.
Moreover, as organisations embrace DevOps principles, the SRE model complements this by emphasising shared responsibility for reliability. Instead of throwing code over the wall to operations, developers and SREs work together to design systems that are resilient by default.
> Becoming a Site Reliability Engineer
If you're interested in becoming a Site Reliability Engineer, there are several routes you can take to get started. Many people begin their careers as software developers or systems administrators before moving into the SRE space.
To set yourself up for success, focus on building your technical foundation. Learn a programming language, get comfortable working with Linux systems, and explore cloud platforms like AWS or Google Cloud. Understanding infrastructure as code, automation tools, and monitoring systems will give you a strong advantage. There are also online courses and certifications specifically designed around site reliability practices that can help you level up.
This is where mthree can support you. If you're a graduate or early in your tech career, we offer training that equips you with the real-world skills employers are looking for. You'll be trained by industry experts in areas like cloud computing, automation, and observability - exactly the kind of tools and knowledge you'll use as an SRE. Once you’ve completed the training, we help place you in a role with a top-tier company, giving you the opportunity to apply what you’ve learned while gaining valuable experience from day one.
More than anything, what you need is curiosity, resilience, and a mindset focused on solving problems. If that sounds like you, a career in site reliability engineering could be a perfect fit.
Discover more about our graduate programme.
> Final thoughts
So, what is a Site Reliability Engineer? In short, an SRE is someone who ensures that complex software systems are robust, scalable, and available. They do this by combining the best of development and operations, using code and automation to solve real-world problems.
With the right mix of site reliability engineer skills and a mindset focused on continuous improvement, SREs play a critical role in modern tech organisations. As systems grow more complex and user expectations rise, the importance of this role will only continue to grow.
Whether you’re considering a career in this field or looking to build out an SRE team, understanding what Site Reliability Engineers do is a valuable first step.
Discover our current roles today and take the first step to becoming a Site Reliability Engineer.
