Security Engineer | Infrastructure (Security, Penetration Testing)

About the Network Engineer Internship at Daangn Daangn is looking for a Network Engineer Intern to join the Infrastructure (Network) team in Seoul. This is a 3-month internship designed for those eager to develop technical skills while supporting a platform that connects hyperlocal businesses and users worldwide. Meet the Network Team The Network Team builds and maintains secure, high-performance network services for Daangn customers. The group designs and operates a network environment tailored for both local and global needs. Team members automate routine tasks, monitor traffic flow and network status in real time, and respond quickly to issues. Maintaining service quality during traffic spikes and protecting the platform from security threats are central to the team’s mission. What You Will Do Help design and operate Daangn’s service and office network architecture (cloud, wired, wireless) Assist in designing and operating network security architecture Contribute to the development and operation of network observability and automation platforms Who We’re Looking For Currently pursuing or recently completed a degree in Computer Science, Information Communication, Information Security, or a related field Solid understanding of basic networking concepts, including the OSI model and TCP/IP Knowledge of IPv4 addressing and subnetting Basic experience with physical network devices such as switches and routers Familiarity with network security concepts, including firewalls Ability to use scripting languages like Python or Bash at a basic level or higher Motivated to learn and grow proactively Preferred Qualifications Hands-on experience with AWS or GCP consoles Understanding of REST API calls and integrations Practical experience with networks or infrastructure through personal projects or coursework Knowledge of security principles such as encryption, authentication, and access control Interest in network observability or automation Attention to documentation and willingness to share knowledge within the team Additional Details This internship lasts for 3 months. Daangn gives preference to candidates with disabilities or veterans, in line with the 'Promotion of Employment for the Disabled and Vocational Rehabilitation Act' and the 'Act on the Honorable Treatment and Support of Persons of Distinguished Service.' Applications close on May 3rd, 11:59 PM. The deadline may change depending on circumstances. The expected start date is June 1st, though this may be adjusted if needed.

Join Our Dynamic Team! As a Network Engineer at Toss Securities, you will be a crucial member of our Network Engineering Team, collaborating closely with Network Security Engineers and IDC Managers. Your role will involve building systems for both external and internal clients while managing our IDC. Work alongside exceptional team members from various sectors, including finance, commerce, portals, and gaming. We are committed to our mission of enabling our teams to focus solely on product development by building robust infrastructure capable of supporting large-scale traffic and promoting automation for faster product launches. Your Responsibilities: Maintain and enhance all network systems at Toss Securities to ensure optimal performance. Design and operate the office network environment for Toss Securities. Architect and implement multi-data center networks to ensure uninterrupted service. Your Qualifications: Minimum of 7 years of experience in network design and operations, specifically with dynamic routing protocols (BGP, OSPF) for multi-data center integration. Strong understanding of various network protocols across L1 to L7 (IP, MAC, TCP, HTTP, SSL, mTLS) and experience in packet analysis. In-depth knowledge and experience of NETWORK OVERLAY technologies (ACI, VXLAN, EVPN, MP-BGP, IS-IS, Fabric). Experience in operating L7 switches with BGP-based Route Health Injection (RHI) for server load balancing. Preferred Qualifications: Experience collaborating with various internet service providers (ISPs) and cloud service providers for multi-data center integration and line load balancing. Background in designing and implementing networking and security devices for large data centers. Familiarity with open-source network monitoring solutions or relevant development experience. Experience in AI data center networking and ANYCAST network services. Experience in automating L2 & L3 switches and L4 & L7 load balancers using APIs. Experience conducting BMT and PoC and writing RFPs. Experience building and optimizing cloud networks, especially in hybrid and multi-cloud environments. Experience using AI-driven MCP for infrastructure operations. Resume Guidelines: Describe your most significant technical problem-solving experiences (optimizations, bug fixes). Detail projects you have contributed to, including duration, role, technology stack, and improvements made. Share experiences of attempts and failures aimed at enhancing network operations. Specify the vendors of the equipment you have worked with. Application Process at Toss Securities: Application Submission > Job Interview > Cultural Fit Interview > Reference Check > Compensation Negotiation > Final Offer and Joining. Please Note: Any discrepancies or disciplinary issues in your resume or work history may result in the cancellation of your application.

Welcome to the Journey of Joining daangn Team!At daangn, we strive to create an environment where individuals can grow alongside the company's expansion. We are dedicated to facilitating moments of joy and collaboration with wonderful colleagues. Introducing the Network TeamThe Network Team aims to deliver secure and high-speed network services to daangn customers. We design and operate a network environment optimized for hyperlocal businesses and a global service network, ensuring that daangn users remain seamlessly connected while being responsible for infrastructure stability and scalability.We enhance efficiency by automating repetitive operational tasks and visualize traffic flow and status across the network in real-time to quickly detect issues and respond proactively. Our core role also involves maintaining service quality during traffic surges and protecting the platform from network security threats.Key ResponsibilitiesDesign and operate daangn's Service/Office Network Architecture (Cloud, Wired, Wireless).Design and operate Network Security Architecture.Develop and operate Network Observability and Automation platforms.Ideal CandidateMinimum of 5 years of practical experience in Network Engineering.Understanding and operational experience with routing protocols such as OSPF and BGP.Experience with AWS or GCP cloud network environments (VPC, TGW, NAT Gateway, Cloud WAN, Direct Connect, Cloud Router, Interconnect).Experience operating wired and wireless network devices (Router, Switch, Wireless Controller, Access Point).Experience with NGFW, IPSEC VPN, and SSL VPN (ZTNA) (AWS Network Firewall, Palo Alto, Fortinet).Experience in building network monitoring systems.Ability to troubleshoot through network packet analysis.No restrictions on overseas travel.Preferred QualificationsExperience in network operations within IT companies or large-scale cloud service environments.Deep understanding of Kubernetes environments.Strong knowledge of Zero Trust frameworks.Experience analyzing network packets to block pattern and signature-based security threats.Interest in developing or automating network monitoring platforms (Go, Python, etc.).Proficient with IaC tools such as Terraform or Ansible.Additional InformationFull-time roles include a 3-month probation period.We prioritize candidates with disabilities and veterans in accordance with the 'Act on the Promotion of Employment of Disabled Persons' and 'Act on the Honorable Treatment and Support of Veterans'.Successful video interview candidates will be given assignments, which will be discussed in the role interview.Application Process1. Document screening → 2. Video interview → 3. Role interview (assignment) → 4. Culture fit interview and reference check → 5. Offer.

Toss Securities is seeking an IDC Infrastructure Engineer (Network & System) to help build and maintain the backbone of our data center operations in Seoul. This position focuses on ensuring the stability, efficiency, and continuous improvement of our large-scale infrastructure, covering everything from network design to physical equipment and operational processes. The role is primarily based at our modern data center (IDC), working closely with a team of network and system engineers. What you will do Design hardware architectures for network and server infrastructure, including equipment selection and implementation standards. Develop data center network architectures (such as Spine-Leaf and redundancy) and server/storage configurations. Define technical standards for bandwidth, NIC specifications (10G/25G/100G/400G), cabling (OM, LR/SR, MPO), and switch port setups. Plan physical infrastructure, taking into account rack space, power, and environmental needs. Set and manage organization-wide standards for equipment models, firmware, and configuration templates. Install, configure, and operate servers, storage, and network equipment on site, driving ongoing improvements. Oversee equipment transport, installation, and relocation, ensuring quality and safety throughout the process. Coordinate with contractors for cabling and equipment setup, maintaining technical standards and quality control. Monitor the IDC environment (power, temperature, network, equipment status) and respond proactively to anomalies. Lead first-level incident response and root cause analysis, working to prevent recurrence and resolve complex issues across network, system, and physical layers. Manage the lifecycle of IDC assets, ensuring data integrity and optimizing long-term operational plans for capacity, power, and space. Collaborate with colocation service providers and partners to manage schedules, quality, and costs. Automate repetitive operational tasks, such as firmware upgrades and configuration deployments, and build monitoring/CMDB integrations using SNMP and REST API. Establish and refine operational standards, procedures, and policies for ongoing efficiency. Requirements At least 5 years of experience in data center (IDC) or infrastructure design and operations. Experience designing data center network architectures (Spine-Leaf, redundancy, etc.). Understanding of server/storage hardware and operating systems (Linux, Windows, Hypervisor). Ability to design at the hardware level, with knowledge of NICs, cabling, and switch ASICs. Experience with IDC space planning, rack layout, power, and space design and operations. Background in large-scale equipment installation, relocation, and asset management within IDC operations. Problem-solving skills that address both physical and logical aspects of incidents. Strong communication skills for effective collaboration with contractors and internal teams. Experience with equipment implementation proof-of-concept (PoC), vendor evaluation, and performance validation. Proven ability to create infrastructure standard documents, such as design guides and operational procedures.

Join Our Team!The Internal Infrastructure Engineer at Toss CX is a vital member of the General Affairs Team, responsible for establishing and implementing optimal internal infrastructure strategies that align with the rapid expansion of our business.This role transcends basic IT support, as you will enhance our network and security systems based on financial security guidelines, ensuring a safe and engaging work environment for all team members.Your Responsibilities:Design and Stabilize Internal IT Infrastructure: Create a scalable internal network and server infrastructure that matches Toss CX's business direction and organizational size, ensuring reliable operations.Manage Office Network and Security Infrastructure: Optimize and maintain the overall office network architecture, including L2/L3 switches and access points. Implement and manage cutting-edge security solutions like Zscaler, NAC, and WIPS to uphold a zero-trust work environment.Enhance IT Governance and Environment: Lead IT projects to establish an account management system based on Okta and Active Directory, standardizing internal infrastructure and maximizing work efficiency.

The Network Engineer role at Toss is part of the Infra Engineering Tribe in Seoul. This team collaborates with System Engineers and InfraOps Engineers to deliver infrastructure that keeps Toss services reliable, fast, and secure. The work supports Toss’s mission to advance financial technology and innovation. Role overview Build and manage network infrastructure for a range of Toss services. Develop and operate monitoring systems to ensure smooth network operations. Optimize network performance, addressing issues to maintain high service quality. Requirements Less than 5 years of experience in network construction. Strong understanding and hands-on experience with L2/L3 data center networks. Demonstrated initiative to improve networks and expand technical skills. Familiarity with TCP/IP and troubleshooting based on it is preferred. Experience working with others to identify and resolve network issues is valued. Experience with IPSEC VPN and L4 (SLB) is a plus. Knowledge of traffic or log monitoring using open source tools is advantageous. Resume tips Describe two memorable cases where technical issues were resolved, such as optimizations or bug fixes. Highlight project contributions, specifying your role, the technology stack, and improvements made before and after your involvement. Hiring process Application submission Job interview Cultural fit interview Reference check Salary negotiation Final acceptance and onboarding

About the Team You Will JoinThe Security Division of Toss Bank consists of various teams including Security Policy, Privacy Protection, System Security, Network Security, Security Red Team, Security Blue Team, IT Service, and Security Audit teams.The Network Security Engineer at Toss Bank will be responsible for the implementation and management of internal and external firewall systems, along with various tasks related to network security, including the operation of DDoS, IPS, and WAF systems.The Security Division collaborates with multiple teams to create a safe and reliable service for Toss Bank. The Network Security Team particularly works closely with product groups, and Legal & Compliance, Platform Engineering, and Internal Audit teams to ensure compliance and internal controls.Toss Bank's Security Division is committed to securing electronic financial transactions for clients and providing a safe working environment for employees.Responsibilities You Will HaveManage and improve network security solutions (FW, DDoS, IDS/IPS, WAF, Suricata) to protect services and employee work environments.Monitor and respond to network attacks and anomalies in real-time, continuously reviewing, tuning, and optimizing detection policies and rules.Design stable network security architecture and lead the construction and enhancement of new systems.Enhance operational efficiency through automation, creating an environment where security personnel can focus on strategic tasks.Ideal Candidate ProfileExperience in building and operating network security solutions (FW, DDoS, IDS/IPS, WAF, Suricata).Ability to analyze network security events/logs and experience in understanding and responding to various attacks.A deeper understanding of enterprise security infrastructure beyond simple equipment operations, focusing on policy, permissions, assets, and risk-based operations.Experience or fundamental understanding of network security architecture design, as well as experience in network troubleshooting and packet analysis (e.g., using Wireshark).Please Include the Following in Your ResumeRather than listing projects, we recommend detailing your roles, contributions, and results with specific examples.If you have experience designing network security architecture, detecting/blocking intrusions through pattern/signature analysis, or participating in drills, please mention them.Especially if you have detailed experiences in building/operating network security solutions or troubleshooting, please describe them thoroughly.

Join Our Team! The Network Engineering team is tasked with establishing Toss Securities' network and security systems, along with managing data center operations. We collaborate with exceptional team members from diverse sectors including finance, commerce, portals, and gaming. Our goal is to support product focus by ensuring infrastructure capable of handling large-scale traffic and driving automation for quicker product releases. Your Responsibilities: Install and maintain Toss Securities' network and security devices, conducting regular status checks and resolving operational issues. Register and manage asset information for network and security devices (serial numbers, status, locations, etc.). Document work logs and change history for installation, migration, and decommissioning tasks. Oversee and enhance Toss Securities' network monitoring solutions. Provide rapid onsite response and first-level troubleshooting during incidents. Plan and support schedules for regular inspections of network and security devices. Be available for night or weekend maintenance when necessary. Manage cable connections for servers and storage, supervising cable installation by contractors. Who We Are Looking For: At least 5 years of experience in network technical support and field engineering. Understanding of network cabling standards and wiring practices is essential. Ability to respond effectively to incidents and perform basic network troubleshooting. Experience in collaborating with maintenance vendors and managing inspection documentation. Operational experience with major network equipment like Cisco and Arista is required; experience with Citrix NetScaler is a plus. Familiarity with security devices such as firewalls and VPNs, alongside a strong understanding of network security is preferred. Application Recommendations: In your resume, highlight a memorable case of technical problem-solving (optimization, bug fixing, etc.). Detail projects you've contributed to, including duration, roles, technology stack used, and improvements made. Your Journey with Toss Securities: Application submission > Job interview > Cultural fit interview > Final acceptance and onboarding. Please Note: This position is a contract role with a duration of one year. Any discrepancies in the resume or disciplinary records may result in cancellation of employment. Applicants subject to hiring restrictions or disqualifications as per Toss Securities' policies may have their applications canceled. Applicants with disabilities or veterans will receive preferential treatment in accordance with relevant laws. A Note for Future Colleagues: “At Toss Securities, you can experience both the constraints of a financial infrastructure and the trendy mobile services of an IT company!” The financial infrastructure in South Korea can be quite restrictive, limiting the breadth of experiences. However, at Toss Securities, you have the responsibility and authority to implement solutions that benefit the business, allowing for valuable experiences without being bound by irrelevant solutions dictated from above.

About the Team You'll Join The Network Security Engineer at Toss Securities is part of the Network Engineering Team, collaborating closely with Network Engineers and IDC Managers. You will work alongside top talents from diverse sectors including finance, commerce, portals, and gaming, focusing on building and supporting secure networks for both external and internal clients. Our goal is to provide robust support for product development, enabling rapid deployment by enhancing our infrastructure to handle large-scale traffic and pushing for automation. Your Responsibilities Upon Joining As a Network Security Engineer, you will be responsible for security devices in the network area, including firewalls, DDoS protection, and VPNs to safeguard Toss Securities' clients and teams. You will perform regular preventive maintenance to ensure the stable operation of security equipment. Management and improvement of Toss Securities' security device monitoring solutions will be part of your role. You will build and operate network security devices, providing security-based technology within the data center. Ideal Candidate Profile A degree in Information Security, Computer Engineering, Information Communication, or a related field is required. A solid understanding of networks and security devices is essential. High proficiency in TCP/IP protocols and experience in packet analysis for troubleshooting are preferred. Experience with security system API integration or work automation is a plus. Prior experience in security training or practical security work is advantageous. Resume Recommendations Please describe a memorable technical issue you resolved (optimization, bug fixes, etc.). Detail projects you contributed to, focusing on your role, technology stack used, and improvements made. The Journey to Joining Toss Securities Application submission > Job interview > Cultural fit interview > Reference check > Salary negotiation > Final acceptance and onboarding. Important Notes False information in your resume or disciplinary issues in your work history may result in cancellation of your application. Applicants who fall under hiring restrictions per Toss Securities policies may also have their applications canceled. Individuals with disabilities or veterans are prioritized according to relevant laws. A Message for Future Colleagues The Network Security Engineer at Toss Securities creates and manages a secure and robust network structure both on-premises and in the cloud. This role goes beyond equipment management; it involves understanding service flows and traffic to continuously innovate better structures. The position requires proactive identification of potential threats and developing solutions. Our team takes initiative to investigate issues, identify root causes, and suggest efficient solutions swiftly, respecting each other's opinions while collaboratively ensuring the stability of financial services. We strive to continuously create improved methods rather than sticking to established practices.

About the Team You'll JoinThe Network Security Engineer at Toss Securities is part of the Network Engineering Team, collaborating closely with Network Engineers and IDC Managers.We work with top talents across various sectors, including finance, commerce, portals, and gaming, to establish and support secure networks for both external and internal customers.Our goal is to ensure that our teams can focus on product development by building robust infrastructure capable of supporting the largest retail securities firm in the market, driving automation for faster product launches. Your ResponsibilitiesAs a Network Security Engineer, you will manage security devices such as firewalls and VPNs to protect our customers and teams.Maintain a reliable, high-availability network that operates 24/7, continuously improving its resilience.Collaborate on the design and implementation of networks that interact with applications and servers.Build and operate network security devices, providing security foundation technologies within the data center. Who We Are Looking ForA minimum of 5 years of experience in building and operating network security devices.Experience in analyzing, optimizing, and maintaining firewall policies is essential.Strong understanding of TCP/IP protocols with packet analysis experience for troubleshooting.Experience with API integration of network security devices or scripting for automation is a plus.Familiarity with financial information protection regulations and experience in related implementations is advantageous.Experience designing and building security network architectures optimized for high traffic is highly desirable.Experience in public cloud environments (AWS, GCP, Azure) is a strong plus. Resume RecommendationsPlease describe a memorable technical issue you resolved (optimization, bug fix, etc.).Detail your contributions to projects, including your role, technologies used, and outcomes before and after the project. Journey to Joining Toss SecuritiesApplication submission > Technical interview > Cultural fit interview > Reference check > Salary negotiation > Final acceptance and onboarding. Please NoteAny inaccuracies in your resume or disciplinary history during employment may result in cancellation of the hiring process.Candidates identified as ineligible according to Toss Securities' regulations may have their applications canceled.Persons with disabilities and veterans will be given preference in accordance with applicable laws.

About the Team You Will JoinThe Security Infrastructure team is dedicated to designing security architectures that ensure the safe expansion of Toss's business, implementing and automating these architectures in real-world environments.This team covers cloud, network, and endpoint security, directly designing and implementing security policies and controls based on key infrastructure.We select technology stacks, create log architectures, and access control models, building a structure that defends against actual threats rather than merely implementing security for security's sake.Our team consists of members with diverse experiences, primarily from corporate information security roles and specialized information protection companies.We are looking for individuals who start with the question of “Why?” to improve security structures and design safer, more efficient methods while balancing technology and business needs.Responsibilities You Will UndertakeDevelop and manage information security solutions that protect Toss's services and employee environments.Establish and operate an access control system for internal information systems.Build a network separation environment and information leak response systems in accordance with financial compliance.Plan and operate systems to enhance security visibility and access control systems.Conduct modern threat analysis and incorporate global trends while establishing AI-based detection and analysis systems and real-time response strategies.Additional ResponsibilitiesDesign, build, and operate infrastructure security architectures across cloud (AWS/GCP/Azure) and on-premises/hybrid environments, covering networks, servers, databases, and containers. You may focus on either cloud or network based on your strengths.Design and reliably implement core security policies like IAM, network segmentation, access control, and encryption (KMS) in real environments.Structure repetitive security operations based on IaC and automation while collaborating with other teams to establish actionable security standards.Analyze security events and breach incidents to design and fundamentally improve security structure, policies, and automation.Ideal CandidateWe are searching for individuals with over 3 years of relevant experience.You should have experience dealing with infrastructure across cloud, network, and systems, not limited to one area.Experience in enhancing detection and response systems using security solutions like CSPM/CNAPP, SIEM, EDR, WAF, and KMS is essential.Experience in designing or improving operational efficiency through security automation and IaC with tools like Terraform/CloudFormation, Ansible, and Python is required.You should have experience interpreting and integrating security requirements in financial and regulatory environments (ISMS-P, ISO27001, PCI-DSS).

About the Team You Will Join The Internal System Engineer position at Toss Securities is responsible for managing in-house infrastructure and IT support, collaborating closely with IT Managers and Internal Network/System Engineers. You will design both wired and wireless networks for the headquarters and remote locations, while integrating user-centric security technologies to create a seamless work environment. Your role will focus on enhancing internal infrastructure and operational efficiency, allowing Toss Securities colleagues to concentrate on their work. Your Responsibilities Upon Joining Establish and operate in-house VDI/HCI/virtualization infrastructure. Oversee the deployment and management of the Horizon VDI environment. Build and manage the necessary servers and HCI infrastructure. Streamline repetitive tasks through automation and scripting solutions. We Are Looking for Someone Who Has experience in building and managing servers based on Windows and Linux. Is capable of establishing and operating hypervisor environments such as VMware and Docker. Can manage VMware Horizon-based VDI environments. Possesses experience in setting up and operating various infrastructure services such as DNS, DHCP, AD, and SMB. Has basic knowledge of NAC, VPN, and DLP technologies. Has experience in establishing and managing monitoring tools like Prometheus, Grafana, and Zabbix. Is proficient in automation development using Python, PowerShell, and Ansible. Journey to Joining Toss Securities Application > Job Interview > Cultural Fit Interview > Reference Check > Salary Negotiation > Final Acceptance and Onboarding Please Note If any false information is found in the resume or if disciplinary actions are confirmed during employment, the recruitment may be canceled. Applicants who fall under the hiring restrictions or disqualifying reasons according to Toss Securities regulations may have their applications canceled. Individuals with disabilities or who are veterans will be given preferential treatment according to relevant laws. A Word for Future Colleagues> "You can experience everything as a System Engineer." - I joined Toss Securities after working as a System Engineer in a mobile service company with large traffic. In my previous role, I managed numerous platforms, but at Toss Securities, I realized I had a superficial understanding of infrastructure operations. Here, I closely collaborate with various departments and gain a comprehensive understanding of the overall architecture. I recommend Toss Securities for System Engineers who are eager to learn, passionate about their work, and seeking the best environment for a career quantum leap!

About the Role tosscareers is hiring an Infrastructure Automation Engineer in Seoul. This role focuses on building and maintaining automated systems that improve the efficiency and reliability of IT services. The position involves hands-on work designing, implementing, and supporting infrastructure automation. What You Will Do Design automated solutions for managing infrastructure Implement and maintain automation tools and workflows Support the stability and scalability of IT services through automation Who We’re Looking For Experience or strong interest in cloud technologies Familiarity with automation tools and systems Motivated to improve IT operations through automation

Team and Collaboration The Security team at Toss brings together a range of professionals: CISO, Security Engineers, Security Researchers, Information Security Managers, Privacy Managers, and IT Managers. This group works closely with the Infra team, product development silos, Legal, and Compliance to build secure services for Toss. Members also connect with security peers across subsidiaries, sharing knowledge and collaborating on specialized areas. Working here means helping to build and improve security systems that support Toss in delivering reliable services. What You Will Do Design and operate AWS cloud security architecture, managing cloud security infrastructure such as CSPM and CWPP. Set up detection and response systems using logs, and automate security policies with IaC tools like Terraform. Manage IDS/IPS, WAF, and DDoS protection systems, addressing network vulnerabilities proactively. Design and refine detection policies through traffic and packet analysis, including regular expressions. Collect and respond to security events using SIEM/SOAR, and operate endpoint solutions like EDR and DLP to strengthen organizational security. Lead security design at the service architecture level and support technical compliance requirements. Requirements At least 5 years of experience as an in-house Security Engineer. Hands-on experience building and operating security systems in AWS cloud environments. Background in constructing and managing network security solutions (IDS/IPS, WAF) and capability in traffic and packet analysis, including optimizing detection policies. Experience with SIEM for event correlation analysis and developing threat hunting and response playbooks is preferred. Familiarity with endpoint security solutions such as EDR, AV, and DLP, as well as handling malware responses and configurations, is a plus. Technical experience with security certifications and financial regulations (ISO27001, PCI-DSS, ISMS-P) is advantageous. Resume Tips Describe previous roles with clear examples, emphasizing project contributions, technology stacks, and measurable improvements. Share how you approached and solved challenges, including your thought process. Include experiences where you identified and responded to security threats or resolved technical and managerial issues. Highlight specific cases where you learned and applied new security technologies or addressed emerging threats. Hiring Process Application Job Interview Cultural Fit Interview Reference Check Compensation Negotiation Final Offer and Onboarding Voices from the Team "I enjoy working with exceptional colleagues." One team member who joined after serving as the sole security officer at a previous company shared how building Toss's security infrastructure alongside the team has brought stability and a stronger security posture. This collaborative environment has become a source of pride as the team secures valuable assets together. Toss encourages setting personal goals every half-year, empowering team members to take ownership and collaborate with accomplished peers.

Role Overview Toss Careers is hiring a Systems Engineer to strengthen our backup infrastructure in Seoul. This position focuses on building, maintaining, and improving backup systems that protect critical data and support business continuity. What You Will Do Design, implement, and maintain backup solutions to safeguard company data Work with teams across the company to troubleshoot and resolve backup-related issues Monitor and optimize backup system performance Identify areas for improvement and help refine backup processes over time Location This role is based in Seoul.

At Sendbird, we merge omnichannel AI with world-class, validated communication APIs to empower businesses in creating AI agents that enable meaningful customer connections at scale.Sendbird offers solutions with enterprise-level stability, security, and compliance. Over 4,000 leading global apps, including DoorDash, Match Group, Noom, and Yahoo Sports, trust Sendbird, facilitating over 7 billion conversations monthly through our platform.To date, we have raised a total of $220 million in funding from top-tier Silicon Valley investors, including ICONIQ, SoftBank, Tiger Global, and Y Combinator, and we are the first global unicorn company in Korea with a valuation exceeding 1 trillion won. Our headquarters in San Mateo, California, along with R&D centers and offices in Seoul, APAC, New York, London, Singapore, India, and Canada, reflect our global reach.Internship Opportunity: AI Agent EngineerThe AI Agent Engineering Intern will collaborate with engineering and product teams to build, integrate, and deploy intelligent agents. Throughout the internship, which lasts between 8 to 12 weeks, you will gain hands-on experience from prototyping to production using the latest web frameworks, LLM APIs, and tooling pipelines.Key Responsibilities:Agent Prototyping and DevelopmentDevelop micro-APIs for tasks such as hallucination detection and conversation resolution through prompt engineering.Test and validate the accuracy of AI agents using internal datasets and tools.Integrate backend APIs that support retrieval-augmented generation (RAG), knowledge bases, and custom toolchains.Prompt Engineering and ToolingCreate, test, and fine-tune prompts for various use cases.Establish CI/CD pipelines for prompt versions and agent deployment.Integration and DeploymentEmbed agents into web, chat, and API-centric environments.Implement observability features like logging and dashboards to monitor real-time performance metrics.Collaboration and DocumentationFacilitate close collaboration among team members, including senior engineers, product managers, and UX designers.Ideal Candidate:Proficient in Python with experience in writing clean and maintainable code.Hands-on experience in backend development using server-side frameworks like Django, FastAPI, or Express.Excellent communication skills and experience in collaborative environments, especially in agile teams.Preferred Qualifications:Experience with prompt engineering frameworks (e.g., LangChain).Understanding of cloud platforms (AWS Lambda, Vercel, GCP Cloud Functions).Experience in AI product-related UX design or product management.Familiarity with Django or similar Python web frameworks.What You Will Gain:Deep insights into cutting-edge agent-based AI development and system deployment.Cross-functional collaboration with engineering, product, and design experts.Mentoring from senior AI engineers, with opportunities for full-time transition.Experience with real customer use cases, performance tuning, and production-grade tool utilization.Flexible Work PolicySendbird supports flexible working schedules. Given the importance of collaboration and teamwork, all team members work together in the office at least three days a week. Some roles may require more frequent office attendance, so please discuss specific requirements with your manager.

Join Our Innovative TeamThe Machine Learning Engineer (Infra) will be part of the ML Platform Team within the Product Division at Toss Securities.The primary goal of the ML Platform Team is to create an optimal machine learning platform that enables the efficient and stable development and operation of various AI/ML services at Toss Securities.The ML Engineer (Infra) will focus on maximizing the efficiency of large-scale AI infrastructure, finely controlling resource usage, and enhancing infrastructure performance to its peak. Your Responsibilities Design and operate high-performance AI computing environments reliably.Design and operate top-of-the-line GPU clusters (H100, B300 series) connected via InfiniBand and high-performance storage (400Gbps) within a Kubernetes environment.Beyond merely building infrastructure, optimize networks and storage to extract the full potential of hardware performance. Develop a comprehensive control system for the entire AI infrastructure.Create an observability system to integrate and monitor AI resources distributed across internal infrastructure and external cloud.Implement management features to prevent resource monopolization by specific services and allocate resources precisely based on importance. Create automation tools for the most efficient resource usage.Analyze actual usage patterns to develop tools that recommend 'just-right resources' to avoid waste.Implement features that automatically scale up or down based on real-time model performance or error rates, and reallocate GPUs where necessary. Establish an environment for identifying and resolving model performance bottlenecks.Build profiling environments to accurately pinpoint slowdowns during model training or serving.Support the analysis and improvement of performance degradation causes between hardware and software. Who We Are Looking ForYou have experience building and operating Kubernetes-based ML infrastructures that handle large-scale traffic.You take responsibility for reliably operating live services beyond simple development.You have experience persistently analyzing and debugging to resolve root causes when issues arise.You possess a solid understanding of system resources (GPU/CPU/Memory/Network/Storage) and have experience building monitoring systems for them.You value the process of solving various problems that arise during service operations and strengthening the system. Preferred QualificationsExperience in unified monitoring of resource usage in large-scale clusters.Experience building systems to systematically control resources through Quota and Rate Limits.Experience with open-source platforms like Kubeflow or Kubernetes, including in-depth modifications as needed.Experience analyzing and optimizing bottlenecks at the kernel level using tools like Nsight Systems/Compute or PyTorch Profiler.Experience designing tasks to reduce costs or enhance performance tailored to workload characteristics (Rightsizing, Cost Optimization).Experience leveraging GPU virtualization technologies like MIG and MPS to maximize resource utilization.

Join Our TeamWe are on the lookout for talented individuals who are eager to contribute to setting the global standard for video understanding AI! At twelve-labs, we are developing cutting-edge AI models that efficiently process vast amounts of video data, offering specialized search, analysis, summarization, and insight generation capabilities.Our models are utilized by the world’s largest sports leagues, enabling them to quickly and accurately select highlights from extensive game footage, providing a super-personalized viewing experience. In South Korea, integrated control centers leverage our technology to efficiently explore CCTV footage, responding swiftly to crisis situations. Major broadcasters and studios worldwide employ our models to create content for billions of viewers.As a deep tech startup with offices in San Francisco and Seoul, twelve-labs has been recognized as one of the top 100 AI startups globally by CB Insights for four consecutive years. We have secured over $110 million in funding from renowned VCs and enterprises, including NVIDIA, NEA, Index Ventures, Databricks, and Snowflake. Notably, our AI models, developed in Korea, are the only ones available through Amazon Bedrock. We thrive on creating innovative products with exceptional colleagues and growing alongside our global clientele.At twelve-labs, we operate based on core values that include:A reflective and honest attitude towards oneself and the teamResilience and humility in the face of failure and feedbackA commitment to continuous learning to enhance the team’s capabilitiesIf you enjoy solving challenging problems and growing through the process, the opportunity is here at twelve-labs.About Our TeamOur Infrastructure Team believes that 'data determines the performance of AI models.' We build high-quality data pipelines for the training and evaluation of multimodal AI models end-to-end. We collect, filter, process, and label diverse multimodal data, collaborating with various teams to design training data that can uncover new model capabilities. Additionally, we create evaluation datasets that reflect actual user experiences and develop internal tools to streamline these processes continuously.Your RoleAs an Infrastructure Engineer at twelve-labs, you will design and build core infrastructure to ensure the stable and scalable operation of our AI SaaS platform. You will work with system architectures across various cloud and on-premise environments, constructing robust infrastructure that supports our video AI foundation models. In our rapidly evolving startup environment, you will optimize performance, security, and flexibility while closely collaborating with multiple internal teams.Key ResponsibilitiesDesign and operate multi-tenant architecture for global enterprise clientsDevelop automation and scalable CI/CD pipelines using TerraformBuild flexible infrastructure encompassing various cloud environments such as AWS, GCP, and Azure, as well as on-premisesOptimize secure and efficient cloud infrastructure through advanced monitoring and security systemsDesign scalable architecture to rapidly support new video AI models and servicesCollaborate with PMs, engineers, and researchers to bring AI products to fruitionIdeal CandidateExperience in building and operating infrastructure in cloud environments such as AWS, GCP, or AzureProficiency in using IaC tools like Terraform and Ansible for automation and architecture designFamiliarity with Kubernetes and container orchestration

Welcome to the Journey of Joining the Daangn Team!At Daangn, we are committed to fostering an environment where individuals can grow alongside the company's success.Our recruitment team is here to assist you in achieving those joyful moments of collaboration with amazing colleagues. Introducing the ML Infrastructure TeamThe ML Infrastructure Team within our Infrastructure Department is responsible for developing a robust and scalable machine learning infrastructure that ensures effective service delivery and efficient operation of Daangn’s machine learning-based services. Machine learning is extensively utilized at Daangn to enhance service quality and improve user convenience across various domains, including feed recommendations, ad recommendations, and service operations. The ML Infrastructure Team handles everything from data processing, model training, model serving, to the deployment processes necessary for machine learning service development. Daangn's GenAI Platform Building Serverless ML Training Infrastructure: Vertex AI Pipelines & TFX ML Infrastructure with GCP | 2025 Daangn GCP MeetupYour ResponsibilitiesDevelop and manage model servers and serving systems for efficient deployment of various machine learning models.Develop and maintain ML infrastructure SDKs, frameworks, and training systems used across the organization.Create specialized monitoring systems for machine learning services to detect quality changes early.Implement various optimization methods across the machine learning infrastructure to enhance development iteration speed and resource efficiency.We Are Looking ForA proficient user of one or more programming languages such as Python or C++.Strong understanding of the infrastructure required for training and serving machine learning models.Over 7 years of experience in backend service or machine learning service development/operations.A desire to improve machine learning infrastructure through solid software engineering skills.Experience in developing and operating GPU clusters.Preferred QualificationsFamiliarity with cloud services like AWS and GCP, with practical experience.A deep understanding of the machine learning ecosystem and contributions to open source projects (e.g., TensorFlow, PyTorch, TensorFlow Extended).A keen interest in new technological trends and a willingness to learn.Additional InformationFor full-time hires, there is a 3-month probation period.We prioritize individuals with disabilities and veterans according to the Employment Promotion and Vocational Rehabilitation Act and the Act on the Honorable Treatment and Support of Veterans.Application Process1. Document Screening → 2. Video Interview → 3. Technical Interview → 4. Culture Fit Interview and Reference Check → 5. Compensation Negotiation → 6. Final Acceptance and OnboardingGo to Daangn Joining Journey Guide