Senior Full-Stack Developer

About cside:

cside is the web security company focused on browser intelligence. We leverage deep browser internals knowledge and AI to detect what otherwise goes unnoticed — or is simply too cumbersome to catch. From identifying malicious JavaScript executions to preventing account takeovers and fraudulent account creations, we are building the next generation of defense against sophisticated web threats.

Our team is a highly specialized group of seasoned browser internals experts and real-time distributed systems engineers. We are building the infrastructure required to process complex signals at scale, turning raw browser data into actionable security intelligence.

Backed by $7.7M in pre-seed and seed funding, cside is already trusted by a diverse range of the world's largest brands. Our technology protects massive universities, global fast-food chains, e-commerce giants, online entertainment platforms, payment providers, SaaS companies, crypto exchanges, and travel networks.

This role is fully remote within the United States. While much of our team works remotely across the globe, we bring everyone together twice a year for offsites in tropical locations.

About the role:

We're looking for a full-stack developer to help build the product surface of cside — the dashboard, APIs, and customer-facing tooling that turn billions of raw browser signals into something a security engineer can act on in seconds. You'll work close to the data and close to the customer, shipping quickly against a genuinely hard technical problem.

What you will do:

• Build and ship features across the stack, from API endpoints to the dashboard our customers live in every day

• Design and implement APIs that serve high-volume, low-latency security telemetry

• Work with our real-time data pipeline to surface detections clearly, without drowning users in noise

• Turn complex security signals into interfaces that make the right action obvious

• Own features end to end: design, implement, test, ship, measure, iterate

• Improve performance and reliability of systems processing signals at scale

• Contribute to code review, technical design, and the engineering standards we hold each other to

• Partner with product and security research to take detections from prototype to production

About you:

• 5+ years building production web applications, with real ownership of what you shipped

• Strong TypeScript, and comfort on both sides of the stack (React on the front, Node or similar on the back)

• Experience with real-time or high-volume data systems, and an instinct for where they break

• You care about performance and can explain why something is slow, not just that it is

• Comfortable with ambiguity; you scope your own work and ship without waiting to be told

• You write clearly — code, review comments, and design docs alike

• Genuine interest in web security; you don't need to be an expert, but you should want to become one

• Based in the United States and authorized to work here, with at least 4 hours of daily overlap with US Pacific hours

• Excited to travel for 2-3 company offsites per year

At cside:

Constantly learning and developing better, we grow together

We do not ship half projects, we do not sell snake oil, we don't cut corners - out of respect for our team, our customers and our community, we put a dent in the universe by building good products

Transparency and integrity above all

cside offers:

Quarterly offsite

Generous work from home allowance

Latest Macbook

Stock options

Market rate salary (seed stage)

Take what you need PTO

Our team is invested in your long term career development. If you want to talk at events, we'll make that happen, if you want to learn how to build your own startup one day, we'll offer you a front line seat. cside is built by folks like you.

We're building a world class security company, and we simply want the best people for the job. We do not select or discriminate based on formal educational background, age, skin tone, religion, national origin, sexual orientation, gender identity, disability status, marital status, veteran status… we're welcoming all and celebrate equal opportunities.

Find more English Speaking Jobs in United Kingdom on Arbeitnow