Senior Application Security Engineer
Content + Source + Freshness • 14 Dec 2025 • 95% confidence
Offer value
Strong opportunity with a notable company in a high-demand area of cybersecurity, reflecting robust job security and career development prospects.
- Strong growth prospects in cybersecurity
- Contribution to major security projects
- Supportive of diverse talents
- Requires significant knowledge in application security
Pros
- Opportunity to work with innovative security technologies
- Diverse and inclusive company culture commitment
- Potential to contribute to impactful projects for customers and society
Cons
- May require on-call responsibilities
- Highly competitive field and specifications
- Expectations for collaboration across remote teams may add logistical complexity
Who it's for
Mid to Senior • Remote
Good fit
- Experienced cybersecurity practitioners
- Security engineers keen to work on meaningful projects
- Professionals with a growth mindset and technical acumen
Not recommended for
- Candidates without relevant cybersecurity experience
- Those looking for a strictly in-office role
- Individuals uncomfortable with flexible and dynamic work environments
Motivation fit
Key skills
About the job
At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. Cloudflare was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company.
We realize people do not fit into neat boxes. We are looking for curious and empathetic individuals who are committed to developing themselves and learning new skills, and we are ready to help you do that. We cannot complete our mission without building a diverse and inclusive team. We hire the best people based on an evaluation of their potential and support them throughout their time at Cloudflare. Come join us!
Available Locations: Lisbon, Portugal
About the Department
The Security team at Cloudflare is focused and committed to helping secure both Cloudflare and our customers. The Application and Product Security team at Cloudflare is focused on and committed to securing both Cloudflare and our customers. The Application & Product Security team is responsible for keeping our products, and platforms secure.
What you’ll do
We are looking for a Security Engineer to help us in our mission to build a better internet. Part engineer, part hacker, you will work with our engineering and security teams to build solutions for .
- Work with engineering teams to help secure Cloudflare products and platforms
- Assess products and new feature releases through threat modeling, code review and security testing. Also provide guidance on effective countermeasures
- Contribute to security architecture/design and assist in building and rolling out processes for secure code development and deployment
- Build secure frameworks & libraries that engineering teams can use at scale
- Build internal security tools and automate processes that help fix security problems at a massive scale.
- Managing and prioritizing multiple tasks in accordance with high level objectives
Key skill sets and Knowledge
Security engineers take part in a wide variety of tasks and projects on the team. One individual is not expected to know everything, but a working knowledge in several of the following areas is required:
- Experience in securing large scale distributed systems
- Experience in designing, building and implementing systems
- Experience in assessing the security posture of systems/services
- Experience in penetration testing and providing mitigating controls
- Strong engineering background and programming experience (Python, Golang, Rust, Bash, etc.)
- Strong communication skills and ability to work with remote teams
- Results and goal-oriented
What Makes Cloudflare Special?
We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.
Project Galileo: Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers--at no cost.
Athenian Project: In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we've provided services to more than 425 local government election websites in 33 states.
1.1.1.1: We released 1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy-centric public DNS resolver. This is available publicly for everyone to use - it is the first consumer-focused service Cloudflare has ever released. Here’s the deal - we don’t store client IP addresses never, ever. We will continue to abide by our privacy commitment and ensure that no user data is sold to advertisers or used to target consumers.
Sound like something you’d like to be a part of? We’d love to hear from you!
This position may require access to information protected under U.S. export control laws, including the U.S. Export Administration Regulations. Please note that any offer of employment may be conditioned on your authorization to receive software or technology controlled under these U.S. export laws without sponsorship for an export license.
Cloudflare is proud to be an equal opportunity employer. We are committed to providing equal employment opportunity for all people and place great value in both diversity and inclusiveness. All qualified applicants will be considered for employment without regard to their, or any other person's, perceived or actual race, color, religion, sex, gender, gender identity, gender expression, sexual orientation, national origin, ancestry, citizenship, age, physical or mental disability, medical condition, family care status, or any other basis protected by law. We are an AA/Veterans/Disabled Employer.
Cloudflare provides reasonable accommodations to qualified individuals with disabilities. Please tell us if you require a reasonable accommodation to apply for a job. Examples of reasonable accommodations include, but are not limited to, changing the application process, providing documents in an alternate format, using a sign language interpreter, or using specialized equipment. If you require a reasonable accommodation to apply for a job, please contact us via e-mail at hr@cloudflare.com or via mail at 101 Townsend St. San Francisco, CA 94107.
