---
title: 'Senior Infrastructure Security & Operations Engineer at Unlimit'
canonical: 'https://feeny.ai/job/senior-infrastructure-security-operations-engineer-unlimit-belgrade-rd9kyr52yjz0'
type: 'job'
last_seen: '2026-10-25'
---

# Senior Infrastructure Security & Operations Engineer at Unlimit

- **Company:** Unlimit
- **Location:** Belgrade, Serbia
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-10-19
- **Last confirmed live:** 2026-10-25
- **Apply:** https://jobs.lever.co/unlimit/5586de7e-3746-4d73-94f8-a385c74467c1

## Job description

## About Unlimit

Unlimit is a global fintech ecosystem built to eliminate financial borders holding businesses back. The company provides the extensive infrastructure needed to scale globally, integrating payment processing, multi-currency business accounts, BaaS and crypto gateways into a single, intelligent platform.

Across 17 offices globally, Unlimit bridges hyper-local expertise with a high-capacity financial network, giving companies the agility to expand across regions with operational confidence and speed. Driving the evolution of payments, Unlimit is transforming its infrastructure from human-operated fintech into AI-native financial infrastructure — where APIs are consumed by machines, integrations are negotiated by agents, and systems evolve continuously through intelligent automation. Our next users are not only humans. They are AI agents acting on behalf of humans and businesses.

Unlimit serves more than the needs of businesses today; we are building the nervous system for a borderless global economy.

## What You'll Be Doing

As a Senior Infrastructure Security & Operations Engineer, you’ll be a hands-on technical expert responsible for strengthening Unlimit’s infrastructure security and operational cyber defence capabilities. You’ll combine security engineering, detection and response, vulnerability management, and cloud security expertise to protect our technology ecosystem against evolving threats. A major part of this role will involve transforming traditional security operations through AI-powered and agentic automation. You’ll design and build intelligent security workflows, automate investigations and response activities, and continuously improve the effectiveness and efficiency of our cyber defence capabilities. This role is ideal for an experienced infrastructure or security engineer who combines strong systems engineering fundamentals with practical security operations experience, advanced automation skills, and a passion for building modern, AI-driven security solutions.

## What You’ll Do

Own and continuously improve infrastructure security controls across Unlimit’s global technology environment. Operate and enhance internal Security Operations, including security monitoring, alert triage, incident investigation, and response. Develop and maintain detection engineering capabilities, including SIEM correlation rules, detection use cases, log analysis, and security monitoring integrations. Conduct proactive threat hunting and leverage cyber threat intelligence to identify emerging threats and improve defensive capabilities. Lead technical incident response activities, including investigation, containment, remediation, and post-incident improvements. Manage infrastructure vulnerability assessment and remediation processes, including vulnerability scanning, prioritisation, tracking, and validation. Implement and continuously improve infrastructure hardening and security configurations across servers, endpoints, networks, and cloud environments. Develop and maintain security controls across AWS, Kubernetes, and containerised environments. Own and optimise endpoint protection and detection capabilities, including EDR/XDR technologies. Contribute to network security, directory security, and infrastructure security architecture reviews. Administer, integrate, and continuously improve security technologies, including SIEM, EDR/XDR, vulnerability management, and infrastructure security platforms. Coordinate external penetration testing activities within the infrastructure security scope, validate findings, and support remediation. Provide technical support for IT and Information Security audits, including evidence collection, technical control validation, and remediation of identified gaps. Collaborate closely with Infrastructure, DevOps, Engineering, and Application Security teams to implement practical and scalable security improvements. AI & Agentic Security Automation Design, develop, and maintain AI-powered and agentic security automation as a core part of Cyber Security operations. Build autonomous and semi-autonomous workflows for security alert triage, investigation, enrichment, and response. Develop AI-assisted detection engineering, threat hunting, and threat intelligence processing capabilities. Automate vulnerability analysis, risk-based prioritisation, and remediation workflows. Build custom security integrations, automation scripts, and internal security tools using Python, APIs, and modern AI development frameworks. Leverage LLMs and agentic development tools, including Claude, to improve security operations efficiency and engineering productivity. Ensure AI-powered security workflows incorporate appropriate validation, access controls, and human oversight for sensitive or high-impact actions.

## What We’re Looking For

6+ years of hands-on engineering experience, including at least 4 years in Cyber Security, Infrastructure Security, or Security Operations. Strong technical background in IT infrastructure, systems engineering, cloud engineering, or platform engineering. Proven experience implementing and maintaining infrastructure security controls in complex production environments. Hands-on experience with Security Operations, SIEM, detection engineering, incident response, and threat hunting. Strong understanding of modern cyber attack tactics, techniques, and procedures (TTPs), including MITRE ATT&CK. Practical experience with EDR/XDR, vulnerability management, and security monitoring technologies. Solid understanding of Linux, networking, operating system security, and infrastructure hardening. Experience securing AWS environments, Kubernetes clusters, and containerised workloads. Strong Python development skills and experience building security automation, integrations, and internal tools. Practical experience developing AI-powered and agentic solutions, including LLM integrations, tool orchestration, autonomous workflows, and AI-assisted automation. Experience integrating security controls and automation into infrastructure and DevOps workflows. Ability to independently investigate complex security issues, identify root causes, and implement effective technical solutions. Strong analytical and problem-solving skills, with an engineering-first approach to security. Ability to work independently while collaborating effectively with Infrastructure, DevOps, Engineering, and Security teams. Technical Experience Hands-on experience with several of the following technologies is highly desirable: Security Operations: CrowdStrike, Elastic Security / Elasticsearch, Tenable. Cloud & Infrastructure: AWS, Kubernetes, container technologies, Cloudflare. Engineering & Automation: Python, Terraform, GitLab, REST APIs. AI & Agentic Development: Claude, LLM APIs, agentic frameworks, tool integrations, and AI-powered workflow orchestration.

## Nice to Have

Previous experience in fintech, financial services, payments, or large-scale regulated e-commerce environments. Experience building AI-powered SOC capabilities or autonomous security operations workflows. Experience developing custom detection rules, security integrations, or open-source security tools. Knowledge of infrastructure security architecture and secure cloud design. Experience with offensive security techniques, infrastructure penetration testing, or adversary simulation. Relevant security, cloud, or engineering certifications.

Join Unlimit Team now!

Unlimit is an equal opportunity employer. We believe passionately that employing a diverse workforce is central to our success. We make recruiting decisions based on your experience and skills. We welcome applications from all members of society irrespective of age, sex, disability, sexual orientation, race, religion or belief.

## About Unlimit

## Company Overview
- **One-liner**: Unlimit provides a global payment infrastructure platform enabling businesses to accept and make payments in any currency across multiple regions.
- **Entity Type**: Private
- **Headquarters**: London, United Kingdom
- **Founded**: 2009
- **Founders**: Not publicly available

## Core Business
- Primary industry/industries: Fintech, Payment Processing, Financial Infrastructure
- Target customers: B2B; eCommerce brands, travel & hospitality companies, gaming platforms, subscription businesses, transportation & mobility companies, and entertainment businesses
- Mission or purpose statement: To eliminate financial borders for businesses all over the world

## Products & Services
- **Payment Processing**: Accept payments anywhere with access to over 1,000+ payment methods and 150+ currencies across 200+ locations; includes local licenses and APMs (Alternative Payment Methods), major card brand acceptance, and semi-automated KYC/AML.
- **Multicurrency Account**: A multipayment account for international transfers, card transfers, and local payment methods in 30+ currencies; includes corporate card issuance with customizable levels and limits, seamless FX conversion, and SEPA/SWIFT transfer channels.
- **Unlimit Crypto**: A fiat on-ramp and off-ramp for DeFi, GameFi, and NFTs; accepts global currencies via e-wallets, QR codes, cash, and instant bank transfers with customizable interfaces.
- **Unlimit Banking as a Service (BaaS)**: A configurable API platform offering white-label card issuing (physical and virtual), a single stackable API for financial operations, local and global payment rails (instant SEPA, SWIFT, BACS), and connections to major card brands and 1,000+ APMs.

## Market Standing
- **Valuation/Market Cap**: Not disclosed (private company)
- **Key Metric**: Total Funding — Not publicly available
- **Notable Investors/Partners**: Not publicly available
- **Growth Signals**: Presence on 4 continents with 17 modern offices worldwide; 1,000+ employees; over 200 locations covered; 15+ years of operational experience; actively hiring for roles across multiple regions including Hong Kong, San Francisco, Brazil, and Serbia

## Competitive Advantages
- Extensive global reach with local licenses and direct connections to alternative payment methods
- 15+ years of experience in the payment infrastructure space
- Comprehensive product suite covering payments, multicurrency accounts, crypto on/off-ramps, and BaaS
- Single, stackable API simplifies complex financial operations for clients
- Presence in high-growth markets across LATAM, APAC, Africa, EU, and the UK

## Strategic Focus
- Expanding global coverage and payment method availability (1,000+ methods)
- Deepening capabilities in crypto and digital asset on/off-ramp infrastructure
- Growing the Banking as a Service offering to enable white-label financial products
- Leveraging AI tools to optimize operations and hiring processes
- Continued investment in local licenses to reduce intermediaries for clients

## Why Work Here
- **Culture**: Values-driven culture based on “Take Initiative,” “Explore to Improve,” collaboration, and ownership; described as a melting pot of game-changing ideas with people from diverse paths speaking different languages [unlimit.com](https://www.unlimit.com/careers/)
- **Growth**: Opportunity to work on a constantly evolving business interface in the booming fintech industry; fast career progression within an international environment of top-notch professionals [unlimit.com](https://www.unlimit.com/careers/)
- **Team**: Multicultural team spanning 14 countries; described as a place where “Unlimiters are made, not born” and where people flourish within a unique culture
- **Work Model**: Mix of on-site, hybrid, and remote roles depending on location; open positions include on-site roles in San Francisco, hybrid roles in Hong Kong, and on-site roles in Belgrade and São Paulo [unlimit.com](https://www.unlimit.com/open-roles/)
- **Innovation**: Encourages taking part in creating innovative fintech products for disruptive industries; use of AI tools to support parts of the hiring process [jobs.lever.co](https://jobs.lever.co/unlimit)

## Sources
1. [unlimit.com](https://www.unlimit.com/)
2. [unlimit.com](https://www.unlimit.com/about-company/)
3. [unlimit.com](https://www.unlimit.com/careers/)
4. [jobs.lever.co](https://jobs.lever.co/unlimit)
5. [unlimit.com](https://www.unlimit.com/open-roles/)

## Other roles at Unlimit

- [Fraud & Dispute Analyst](https://feeny.ai/job/fraud-dispute-analyst-unlimit-belgrade-ew5dw3yr7zs5) — Belgrade, Serbia
- [Transaction Monitoring Lead](https://feeny.ai/job/transaction-monitoring-lead-unlimit-limassol-czyzydk6jmw0) — Limassol, Cyprus
- [Client Relationship Manager](https://feeny.ai/job/client-relationship-manager-unlimit-limassol-wg6s46894xk3) — Limassol, Cyprus
- [Senior Processing Development Engineer (SmartVista)](https://feeny.ai/job/senior-processing-development-engineer-smartvista-unlimit-limassol-enr34whmvghr) — Limassol, Cyprus
- [Senior Account Manager (Acquiring)](https://feeny.ai/job/senior-account-manager-acquiring-unlimit-singapore-jzhpskdk27qm) — Singapore
- [Business Development Manager (Hong Kong)](https://feeny.ai/job/business-development-manager-hong-kong-unlimit-hong-kong-r58dzsrh8ddg) — Hong Kong, China
- [Senior Account Manager (Acquiring), Hong Kong](https://feeny.ai/job/senior-account-manager-acquiring-hong-kong-unlimit-hong-kong-8pb6rng37bma) — Hong Kong, China
- [Business Development Manager (Shanghai/Shenzhen)](https://feeny.ai/job/business-development-manager-shanghai-shenzhen-unlimit-shanghai-73n837k5drnc) — Shanghai, China
- [Senior Account Manager (Acquiring)](https://feeny.ai/job/senior-account-manager-acquiring-unlimit-shanghai-hvsn43jcaang) — Shanghai, China
- [Business Development Manager APAC- Singapore (Core Fintech Background)](https://feeny.ai/job/business-development-manager-apac-singapore-core-fintech-background-unlimit-hwe691psr5ak) — Singapore