Infrastructure in Belgrade

Perplexity is seeking an experienced Machine Learning Engineer to improve search quality across the middle and later stages of ranking. We are looking for a strong ranking generalist who can own ambiguous problems end to end and brings exceptional depth in either neural ranking or production ranking systems. Responsibilities Push search quality forward through models, data, evaluation, infrastructure, or any other leverage available. Own ranking-quality problems end to end: define the evaluation, identify the bottleneck, build the solution, and ship it safely. Train and evaluate retrieval, ranking, and classification models, including neural and LLM-based approaches where appropriate. Build and operate ranking infrastructure, including feature computation, low-latency inference, multi-stage cascades, deployment, and monitoring. Make sound trade-offs across quality, latency, reliability, cost, and engineering complexity. Collaborate across Data, AI, Infrastructure, and Product while retaining ownership of the final quality outcome. Qualifications Deep understanding of search or recommender systems and their evaluation. Proven ownership of a large-scale production ranking system or a substantial class of quality problems. Strong machine learning and software engineering skills across data, models, serving, and monitoring. Ability to drive ambiguous, cross-team problems without continuous task decomposition. Exceptional depth in either modern neural ranking methods or low-latency ranking systems and runtime.

DeepIntent is the leading healthcare marketing platform, purpose-built to help marketers plan, activate, and optimize data-driven campaigns with speed and precision. Trusted by the world’s top healthcare brands and their agencies, DeepIntent uniquely unites media, identity, and real-world clinical data to power privacy-safe, omnichannel marketing across every screen. Backed by patented technology and proven outcomes, DeepIntent’s platform delivers measurable audience quality and script lift at scale. Learn more at www.deepintent.com . Location: Banja Luka, Bosnia and Herzegovina (primary) or Belgrade, Serbia What You’ll Do: As a Senior Security Engineer, you will own the security architecture and enforcement across our infrastructure. Our infrastructure relies heavily on a Linux ecosystem, and as we scale our cloud footprint and AI initiatives, this layer is becoming increasingly security-sensitive. You will be embedded directly with the teams operating these systems, bridging the gap between high engineering velocity and secure-by-design architecture. Your core mandate is to protect production, harden our Linux environments, establish AI guardrails, and build secure access patterns without creating process overhead. This role will report to the Sr Director, Infrastructure and Networking and will be a hybrid role based out of Banja Luka, Bosnia. Linux Hardening & Threat Detection: Secure our underlying Linux infrastructure and container runtimes. Deploy, tune, and manage our SIEM for continuous threat detection, file integrity monitoring, and host-based intrusion detection (HIDS) across our fleet. Identity & Access Control: Design and enforce secure access patterns. Ruthlessly eliminate shared accounts, long-lived credentials, and overly broad permissions across the organization. Cloud & Infrastructure Governance: Own the security posture across our cloud environments. Implement secure infrastructure-as-code practices using Terraform an

We are seeking an experienced Backend Software Engineer to join our Crawler team. In this role, you will design, develop, and operate systems that ingest, process, and manage web-scale data in support of our next generation of advanced search technologies. This is a critical, high-impact engineering position, requiring expertise across both backend and frontend components of our data acquisition stack. Responsibilities Take ownership of and lead projects focused on developing large-scale web crawlers, ingestion pipelines, and data processing systems. Build, maintain, and optimize core backend and frontend components for crawler services, including storage, retrieval, and UI dashboards for data management. Collaborate closely with Search and Infrastructure teams to ensure the reliable, high-quality ingestion and processing of billions of web pages. Architect and implement fullstack features and scalable distributed systems that handle high-load and real-time data operations. Rapidly iterate, experiment with novel approaches, and continuously enhance system performance, usability, and reliability. Qualifications Minimum of 5 years of software development experience, with strong knowledge of data structures and algorithms in at least one of the following languages: Python, C++, Rust, or Go. Experience with large-scale web crawlers is highly desirable. Proven experience building, deploying, and optimizing high-load, distributed, and hardware-adjacent services. Deep understanding of cloud infrastructure, with hands-on experience in Kubernetes (K8s) and AWS. Demonstrated passion for writing clean, efficient, and scalable systems.

P-1415 At Databricks, we are passionate about helping data teams solve the world's toughest problems — from making the next mode of transportation a reality to accelerating the development of medical breakthroughs. We do this by building and running the world's best data and AI infrastructure platform so our customers can use deep data insights to improve their business. Founded by engineers, Databricks has started a multi-year journey to build the best Data Intelligence Platform. For this we are building on top of a great foundation but our goal is to go further to build dramatically better products. We want to revisit every component to provide our customers with the fastest, easiest to use and most secure data platform for all their data workloads. As a software engineer, you will join as a founding member of not only the Belgrade site, but really as a founding team for our multi-year journey to achieve our Lakehouse vision. You will be involved in the entire development cycle and exemplify all core Databricks values. The impact you'll have: Our backend teams span many domains across our essential service platforms. For instance, you might work on challenges such as: Problems that span from product to infrastructure including: distributed systems, at-scale service architecture and monitoring, workflow orchestration, and developer experience. Build reliable, secure and high performance services and client libraries for storing and accessing humongous amount of data on cloud storage backends, e.g., AWS S3, GCS, Azure Blob Store. Develop product features that empower our customers to easily store and access their data. What we look for: BS (or higher) in Computer Science, or a related field 5+ years of production level experience in one of: Java, Scala, C++, or similar language Experience developing large-scale distributed systems Experience working on a SaaS platform or with Service-Oriented Architectures Knowledge of SQL About Databricks Databricks is the D

Perplexity is seeking an experienced Machine Learning Engineer to help build the next generation of advanced search technologies, with a focus on retrieval and ranking. Responsibilities Relentlessly push search quality forward—through models, data, tools, or any other leverage available Architect and build core components of our search platform and model stack Train and evaluate retrieval, ranking and classification models, including LLMs Deploy models - from boosting to LLMs - in a scalable and performant way Build and optimize RAG pipelines for grounding and answer generation Collaborate with Data, AI, Infrastructure and Product teams to ensure fast and high quality delivery Qualifications Deep understanding of search and retrieval systems, including quality evaluation principles and metrics Proven track record with large-scale search or recommender systems Self-driven, with a strong sense of ownership and execution Minimum of 5 years of working on search or recsys-related projects

Job Overview Wargaming is looking for a proactive and hands-on Facility Officer to join our team in Belgrade. In this role, you will help ensure that our office facilities are safe, functional, and well-maintained, supporting smooth day-to-day operations and providing a comfortable working environment for our employees. You will be responsible for carrying out basic maintenance tasks, monitoring the condition of office facilities and equipment, coordinating external contractors and service providers, and assisting with workspace arrangements and office logistics. This role is ideal for someone who enjoys practical work, takes initiative, and can efficiently handle a variety of facility-related tasks. Reports to Head of Workplace & Employee Experience What will you do? Assists with maintaining daily operations of the physical facility. Supports maintenance mechanics and facilities staff by performing “handyman” maintenance duties such as furniture moves, simple electrical projects Works with outside contractors on building and equipment repairs Operates site equipment as needed, using hand and power tools as necessary Coordinates vendors/employees for performance of specialized maintenance, repair, or certification of buildings, infrastructure, tech appliances. Inspects completed work for conformance with contract requirements and safety codes Performs regular checks of buildings, infrastructure, and premises to ensure safety and uninterrupted use Organize storage areas, inventory management Providing support to office team in everyday operations: assist with setting up workspaces for new employees Arrange furniture and office equipment as needed Provide logistical support for meetings, events, and office functions What are we looking for? Previous experience in facility maintenance, handyman services, technical support, or a similar hands-on role. Practical skills in basic

Job Overview Wargaming is looking for a Performance QA Team Lead to join our World of Warships PC team. In this role, you’ll lead the Performance QA team, drive performance testing and automation using Python, and help ensure the game delivers a smooth and stable experience for players. We’re looking for a technical leader with a strong and broad background in performance engineering, who can combine hands-on expertise with team leadership and help us continuously improve our performance testing practices. Reports to Head of QA What will you do? Lead the Performance QA team: task planning, coordination, mentoring, and technical guidance Define and maintain performance testing strategy, coverage, baselines, thresholds, and regression criteria Investigate performance regressions, identify bottlenecks, and drive root-cause analysis across client, backend, and system-level components Drive performance testing and automation across game client, backend services, network interactions, and system-level scenarios Create and maintain test infrastructure, tools, and frameworks for QA team Maintain documentation for performance tests, tools, and testing processes Collaborate with development and other teams to analyze performance results and drive improvements Integrate and maintain performance testing within CI/CD pipelines Participate in architectural and technical design reviews from a QA perspective What are we looking for? 4+ years of experience in Performance QA, Performance Engineering, or related areas Experience in leading QA teams or technical leadership 2+ years of professional experience with Python Strong understanding of performance engineering principles and the ability to investigate performance issues across complex systems Experience in at least one of the following areas: client performance, backend/load performance, distributed systems, or system-level performance analysis Upper-Interme

Perplexity is looking for a Search Machine Learning Engineer Intern to help build the next generation of advanced search technologies, with a focus on retrieval and ranking. You will work closely with experienced engineers to improve search quality, experiment with new models, and ship features that directly impact how users search and discover information. Internship program: 12 - 24 weeks, full-time, part-time, in-person in the Belgrade office. Responsibilities: Contribute to experiments that improve search quality through better models, data usage, and evaluation tools, under the guidance of senior engineers. Design and implement components of the search platform and model stack, including retrieval, ranking, and classification models. Train evaluating models (including LLM-based approaches) for retrieval, ranking, and classification tasks. Support deployment and monitoring of search and ranking models in a scalable and performant way. Help build and iterate on RAG pipelines for grounding and answer generation. Collaborate with Data, AI, Infrastructure and Product teams to deliver improvements quickly and learn best practices in production ML. Qualifications: Strong foundation in machine learning and statistics, with coursework or projects related to information retrieval, ranking, or recommender systems. Experience with Python and common ML frameworks (e.g. PyTorch, TensorFlow, JAX) through academic, open source, or personal projects. Familiarity with evaluating model quality using offline metrics and/or A/B testing is a plus, but not required. Previous experience (internships, research, or significant projects) working on search, recommendation, or NLP is a plus, but not required. Self-driven and curious, with a strong sense of ownership, willingness to learn, and comfort working in a fast-paced environment Experience with Rust will be a plus What we're looking for: You’ve built something you’re proud of: Not just a class assignment - we want to see a project y

P-1439 As Applied ML/AI Engineer at Databricks, you will define and create the Agentic Machine Learning revolution. You will help world’s largest companies build and deploy massive classical machine learning solutions (such as personalized recommendations, fraud detection, dynamic pricing, forecasting) fully using Databricks’ agents and harnesses. After 30 years of painfully slow progress, expensive knowledge acquisition and tedious processes in classical ML, the agentic era has ushered innovation, scale and visibility for all: from the most junior data scientists and machine learning engineers to the world class experts. You will work on Databricks’ Genie Code, an agent and an ML “exoskeleton” that is authoring ML, training and deploying models, monitoring and self-healing production ML, all at the top-expert level. Additionally, you will develop ML solutions that under the hood address the most pressing questions non-technical business people have today: predictive and what-if questions. Your work is a top priority for Databricks and you will report to a Principal Software Engineer (a Director level position). The impact you will have: Build agentic end-to-end systems in a small, highly international team of experienced engineers in a flat and agile organization. Build solutions for people like you: software engineers, ML engineers, data engineers, data scientists and MLOps engineers. Own our applied ML investment by engaging with engineering and product teams across the company. Drive the development and deployment of state-of-the-art ML/AI models and systems that directly impact the capabilities and performance of Databricks’ products, infrastructure, and services. Architect and implement robust, scalable ML infrastructure, including model training and serving components to support seamless integration of AI/ML models into production environments. Work on novel forecasting techniques. Possibilities to contribute to the broader AI community by presenting a

Perplexity is looking for a highly skilled Senior or Expert Systems Engineer to join our Search Core team. This role is critical to building next-generation search products and technologies. You will help drive key decisions around the architecture, design, and implementation of foundational components in our technical stack. Responsibilities Design and build core search engine components, including indexing pipelines, retrieval algorithms, and ranking systems that operate at the scale of billions of pages Develop streaming and batch data processing systems for search index construction in a high-load environment Push the limits of hardware performance through low-level optimizations and systems-level tuning Tackle challenges in multithreading, concurrency, and system-level optimization Qualifications 3+ years of hands-on experience in systems programming (Rust, C++, C, or similar) Ownership of full project lifecycle — you don't just write a fast inner loop, you care about how the system is built, deployed, operated, and scaled in production Knowledge of Python or other scripting languages Passion for writing clean, efficient, and scalable systems-level code Strong knowledge of algorithms and data structures, and the ability to apply them effectively Deep understanding of multithreading, including various approaches, challenges, and trade-offs Experience building high-load, distributed, and hardware-adjacent services Solid understanding of Linux internals (syscalls, networking stack, memory model, kernel tuning) Familiarity with low-level optimization techniques (memory management, cache efficiency, SIMD, profiling) Preferred Qualifications Experience developing core components of search engines, databases, or information retrieval systems Understanding of search fundamentals: indexing, query parsing, ranking, and relevance Experience with trading systems or other latency-sensitive real-time systems Familiarity with cloud services, Kubernetes, and AWS infrastructure