Senior Backend Software Engineer Application Development Jobs

About the Role Discover your future at Citi Working at Citi is far more than just a job. A career with us means joining a team of more than 230,000 dedicated people from around the globe. At Citi, you'll have the opportunity to grow your career, give back to your community and make a real impact. Job Overview Citi's Integrated Digital Assets Platform (CIDAP) is at the vanguard of institutional blockchain adoption — and security is its foundation. As digital assets move from innovation to regulated infrastructure, the cryptographic integrity of every transaction, wallet, and key lifecycle operation becomes mission-critical. We are building the security layer that the world's most sophisticated financial institution can trust. We are seeking a Senior Security Engineer (VP) to join our New York-based Digital Assets Platform engineering team. This is a hands-on, Java-focused backend engineering role for a security-minded engineer who understands both the craft of secure software development and the cryptographic primitives that underpin digital asset custody, signing, and key management. You will sit inside the core engineering team — writing production code every day — while being the resident authority on cryptographic design patterns, HSM integration, MPC protocols, and security architecture. Your work will directly protect billions of dollars of digital asset infrastructure used by institutional clients worldwide. Key Responsibilities Design, develop, and maintain security-critical backend services in Java — including cryptographic libraries, key management APIs, signing wor

WPP is the trusted growth partner for the world’s leading brands. We unite cutting-edge media intelligence and data solutions, world-class creativity, next-generation production, transformative enterprise solutions and expert strategic counsel in a single company – powered by exceptional talent and our agentic marketing platform, WPP Open, to help our clients navigate change, capture opportunity and deliver transformational growth. We work with the world's most valuable brands and have global reach across 100+ markets, with deep local expertise. Our people are the key to our success. We're committed to fostering a culture of creativity, belonging and continuous learning, attracting and developing the brightest talent, and providing exciting career opportunities that help our people grow. For more information, visit WPP.com. Why we’re hiring We’re growing the data engineering capability behind ad-tech solutions that process large-scale, real-time audience data. In this role, you’ll take deep technical ownership of the data model that supports targeting and measurement decisions for advertisers at scale. You’ll help evolve a complex, interconnected data platform while working with modern distributed processing technologies and a highly collaborative engineering team. Who you’ll be working with You’ll work closely with data engineers and colleagues across Quality Assurance, Analytics and connector teams. We value teamwork over ego, collaboration over competition, open and honest communication, strong opinions held with curiosity, and continuous improvement through kaizen. Our technology environment Scala-based backend services Google Cloud Platform (GCP) Apache Spark for large-scale distributed data processing Parquet and BigQuery Tyda, an open-source, automation-driven software development lifecycle process What you’ll do Own and evolve a core data model spanning input and output models, field types and partitioning strate

The Infrastructure Engineering team is responsible for building and maintaining a self-service internal development platform that enables MongoDB engineering teams to reliably deploy and operate their own production services and products. We work with numerous engineering teams across the company to understand their infrastructure requirements and development workflows, develop broadly applicable self-service platform services and tooling, continuously monitor how platform services are being utilized, and look for ways to improve developer productivity through automation and education. We are big open source enthusiasts and use a number of open source tools in our stack (contributing upstream whenever possible). Some of the tools we use regularly include Go, AWS, Kubernetes, Crossplane, Terraform, Helm, Drone, Prometheus, and Grafana. However, technology is nothing without a stellar team of engineers that are focused on doing high quality work and working as a team to solve complex distributed computing and platform engineering problems. This is where you come in! We are looking to speak to candidates who are based in Gurugram for our hybrid working model. Our ideal candidate Has built and operated large-scale distributed systems in cloud providers (AWS strongly preferred) Has a strong backend programming background. Fluency in Go is strongly preferred; deep experience with another compiled or strongly-typed backend language is acceptable Has experience working with AI coding agents and can demonstrate building high quality context to yield high quality outputs Has experience designing and implementing medium-to-large software projects, including driving design reviews and mentoring less-senior engineers Pragmatic, detail-oriented, self-motivated, and understands the benefits of collaboration Strong experience operating production Kubernetes clusters, not just deployed to it Has practical experience defining and operating against SLI/SLOs for services they owned Str

GitLab is the intelligent orchestration platform for DevSecOps. GitLab enables organizations to increase developer productivity, improve operational efficiency, reduce security and compliance risk, and accelerate digital transformation. More than 50 million registered users and more than 50% of the Fortune 100* trust GitLab to ship better, more secure software faster. The same principles built into our products are reflected in how our team works: we embrace AI as a core productivity multiplier, with all team members expected to incorporate AI into their daily workflows to drive efficiency, innovation, and impact. GitLab is where careers accelerate, innovation flourishes, and every voice is valued. Our high-performance culture is driven by our values and continuous knowledge exchange, enabling our team members to reach their full potential while collaborating with industry leaders to solve complex problems. Co-create the future with us as we build technology that transforms how the world develops software. * Fortune 500® is a registered trademark of Fortune Media IP Limited, used under license. Claim based on GitLab data. Fortune 100 refers to the top 20% ranked companies in the 2025 Fortune 500 list, published in June 2025. Fortune and Fortune Media IP Limited are not affiliated with, and do not endorse products or services of GitLab. An overview of this role As a Backend Engineer on the Chat Engine team, you'll build the engine behind GitLab Duo Chat, the conversational AI experience for GitLab. You'll work primarily in Python to build and maintain our agentic runtime: the Flow Registry, LangGraph flows, and the Duo Workflow Service. You'll also work in the GitLab Rails monolith, where Chat connects with the product. You'll own scoped parts of the system, ship small features and improvements with minimal guidance, and collaborate with the team on larger projects. You'll work alongside senior and staff engineers who will partner with you on design and support

GitLab is the intelligent orchestration platform for DevSecOps. GitLab enables organizations to increase developer productivity, improve operational efficiency, reduce security and compliance risk, and accelerate digital transformation. More than 50 million registered users and more than 50% of the Fortune 100* trust GitLab to ship better, more secure software faster. The same principles built into our products are reflected in how our team works: we embrace AI as a core productivity multiplier, with all team members expected to incorporate AI into their daily workflows to drive efficiency, innovation, and impact. GitLab is where careers accelerate, innovation flourishes, and every voice is valued. Our high-performance culture is driven by our values and continuous knowledge exchange, enabling our team members to reach their full potential while collaborating with industry leaders to solve complex problems. Co-create the future with us as we build technology that transforms how the world develops software. * Fortune 500® is a registered trademark of Fortune Media IP Limited, used under license. Claim based on GitLab data. Fortune 100 refers to the top 20% ranked companies in the 2025 Fortune 500 list, published in June 2025. Fortune and Fortune Media IP Limited are not affiliated with, and do not endorse products or services of GitLab. Intermediate Fullstack Engineer - Data Products An overview of this role Data Products integrates GitLab and third-party software development lifecycle data, and builds the dashboards, APIs, and data products that turn it into reliable, interoperable intelligence for customers and internal teams. You'll work across the stack, contributing to frontend experiences, backend services, APIs, and AI-enabled workflows. This is a hands-on product engineering role. You'll develop features, learn how we build and operate large-scale data systems, and work closely with Senior and Staff Engineers to deliver secure, reliable, and performant s

Ignite your curiosity. Solve the unsolvable. At Leidos, we do more than write code—we decode the unknown. Our San Diego-based research and engineering team takes on some of the nation’s toughest defense challenges using advanced signal processing, ocean remote sensing, and high-performance computing. We’re seeking a Software Engineer / Computer Scientist who enjoys solving complex problems and pushing the limits of performance. In this role, you’ll work alongside a multidisciplinary team of scientists and engineers with expertise in hydrodynamics, physics, acoustics, and signal processing to build impactful software that turns massive, complex data sets into meaningful insight. If you are motivated by innovation, energized by collaboration, and excited to see your work support real-world missions, this could be the right opportunity for you. What You’ll Do Collaborate with scientists and engineers to design, develop, and optimize advanced algorithms for next-generation radar, optical, and infrared sensor systems. Build scalable, high-performance backend systems for scientific computing in distributed environments. Integrate, refactor, and improve scientific codebases to increase efficiency and scalability. Translate and optimize existing code for GPU/CUDA acceleration and parallel or distributed execution. Test, document, maintain, and enhance complex software in Linux/Unix environments. Contribute in a collaborative environment that values technical excellence, creativity, and continuous growth. Required Qualifications Bachelor’s degree in Computer Science, Applied Mathematics, Physics, or a related field with 4+ years of backend software development experience, or a Master’s degree with 2+ years of experience. Equivalent experience may be considered in place of a degree. U.S. citizenship and the ability to obtain a Top Secret clearance; active Top Secret clea

At Affirm, we exist for the moments that matter—giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most. The Fraud Engineering organization builds the foundational and tactical software that enables Affirm to respond strategically to fraud - both in real time and after the transaction. Our mission is to support business growth while protecting Affirm, our buyers, and our merchants. We evaluate risk at critical decision points in the user journey, rapidly adapt to evolving fraud patterns, and equip operations teams with the tools needed to investigate and mitigate fraud at scale. We’re looking for a Senior Software Engineer to join our fully remote team based in Europe. You’ll collaborate closely with stakeholders across North America - including teams in Product, Compliance, Machine Learning, Fraud Operations, Fraud Strategy, and other Fraud Engineering teams. The Fraud Engineering organization builds the foundational and tactical software that enables Affirm to respond strategically to fraud - both in real time and after the transaction. Our mission is to support business growth while protecting Affirm, our customers, and our merchants. We evaluate risk at critical decision points in the user journey, rapidly adapt to evolving fraud patterns, and equip operations teams with the tools needed to investigate and mitigate fraud at scale. The Fraud International Team (FIT) leads the engineering effort to extend Affirm's Fraud Decisioning System into markets beyond the US - Canada, the UK, Australia, and growing rapidly. We own real-time fraud decisioning for these markets, integrate region-specific risk vendors, and are building the platform that lets Affirm stand up fraud protection in a new country quickly and safely. As Affirm expands globally, FIT scales with it. We're looking for a Senior Software Engineer to join our fully remote team based in Europe. You'll collaborate closely w

At Affirm, we exist for the moments that matter—giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most. The Fraud Engineering organization builds the foundational and tactical software that enables Affirm to respond strategically to fraud - both in real time and after the transaction. Our mission is to support business growth while protecting Affirm, our buyers, and our merchants. We evaluate risk at critical decision points in the user journey, rapidly adapt to evolving fraud patterns, and equip operations teams with the tools needed to investigate and mitigate fraud at scale. We’re looking for a Senior Software Engineer to join our fully remote team based in Europe. You’ll collaborate closely with stakeholders across North America - including teams in Product, Compliance, Machine Learning, Fraud Operations, Fraud Strategy, and other Fraud Engineering teams. The Fraud Engineering organization builds the foundational and tactical software that enables Affirm to respond strategically to fraud - both in real time and after the transaction. Our mission is to support business growth while protecting Affirm, our customers, and our merchants. We evaluate risk at critical decision points in the user journey, rapidly adapt to evolving fraud patterns, and equip operations teams with the tools needed to investigate and mitigate fraud at scale. The Fraud International Team (FIT) leads the engineering effort to extend Affirm's Fraud Decisioning System into markets beyond the US - Canada, the UK, Australia, and growing rapidly. We own real-time fraud decisioning for these markets, integrate region-specific risk vendors, and are building the platform that lets Affirm stand up fraud protection in a new country quickly and safely. As Affirm expands globally, FIT scales with it. We're looking for a Senior Software Engineer to join our fully remote team based in Europe. You'll collaborate closely w

Must be based in Vancouver The role We're hiring a dedicated data engineer to own the production data platform that our delivery, product, and engineering teams run on; designing integrated, governed data pipelines and delivering automated reporting, AI-assisted workflows, and predictive signals on top of them. You'll write production code, design systems, own CI/CD, and be accountable for the correctness of data that leaders make decisions on. What you'll do Design and operate our cloud data platform: ingestion, transformation, orchestration and serving. Integrate data from across the business (delivery tooling, CRM, product telemetry, finance, support and customer feedback systems) with shared identifiers, data contracts and lineage. Build automated and continuously refreshed reporting so teams manage by exception rather than chasing status. Connect approved AI agents to governed data with structured outputs, provenance, guardrails and human approval in the loop. Build feature pipelines and the MLOps controls behind predictive use cases: tests, versioning, promotion gates and drift monitoring. Own the engineering standards for data: testing, observability, environment promotion, PII classification and access control. What you'll bring Strong software engineering fundamentals: production-quality code, API and interface design, testing discipline, systems design. Real experience building and operating production data platforms on a cloud warehouse or lakehouse (Snowflake and AWS preferred) with dbt and a modern orchestrator. Practical AI tooling experience: something shipped, not prototyped. LLM-backed classification, extraction or structured-output pipelines; agent and tool-calling workflows; retrieval; evals. You can reaso

Become a part of our caring community The Senior Full Stack Engineer Performs software engineering activities in all layers of the stack, from setting up the database to programming in the back-end and the appearance at the front-end. The Senior Full Stack Engineer works on problems of diverse scope and complexity ranging from moderate to substantial. You will report to the Associate Director of Software Engineering. The Senior Full Stack Engineer is involved in all stages of software development. This includes front-end development, back-end development, database integrations, network and hosting management, user interface, user experience, and back-end server management. You are experienced with Cloud-based services and development end-to-end. You can work with autonomy while collaborating with others on architectural and process decisions. You are comfortable with giving and receiving feedback from your teammates and others in the organization. You conceptualize what you need to do from incomplete and evolving requirements. Experience communicating updates and resolutions to customers and other partners. On any given day you may: Contribute to technical architecture reviews and design as well as present vision Expertise using advanced data structures and algorithms Possess the ability to evaluate problems in both strategic and tactical terms Mentor and assist in coaching a small team of high-caliber engineers Drive positive change with technical vision and innovative solutions Strong affinity to software-driven engineering & automation Partner with the business and stakeholders to define technical direction & work cross functionally Deliver business-critical systems and compon

Are you looking for an opportunity to help solve one of today's biggest business challenges? AI is changing the pace of business, and organizations everywhere are struggling to help their workforce, partners, and customers keep up. At Litmos, we're building the Learning Acceleration Platform that helps organizations build human capability faster—and we're looking for people who are passionate about making a meaningful impact for customers while growing alongside a collaborative, people-first team. Litmos is the Learning Acceleration Platform that helps organizations build capability faster, adapt at the speed business changes, and scale learning to anyone, anywhere. Combining an intuitive platform, AI-powered capabilities, trusted content, expert services, and a broad ecosystem of integrations, Litmos helps organizations accelerate workforce productivity, improve customer adoption and retention, enable high-performing partners, and reduce organizational risk through continuous learning. Organizations such as Hewlett Packard Enterprise, Graco, Sabre, and Russell Mineral Equipment trust Litmos to accelerate learning across their workforce, partners, and customers. Today, more than 11K customers with 30 million learners across 150 countries and 37 languages use Litmos to build the capabilities their organizations need to succeed. Backed by Francisco Partners, one of the world's leading technology investment firms, we're investing in the future of learning—and the people who are building it. Learn more at www.litmos.com . We are looking for a Senior Full Stack Engineer to build and evolve our platform using .NET, React, and SQL Server-based systems. You will work across services, APIs, and front-end systems with a focus on scalability, reliability, and maintainability. You will operate within a globally distributed Agile team (Scrum and ShapeUp), where engineers own delivery, from design through deployment, while collaboratin

Are you looking for an opportunity to help solve one of today's biggest business challenges? AI is changing the pace of business, and organizations everywhere are struggling to help their workforce, partners, and customers keep up. At Litmos, we're building the Learning Acceleration Platform that helps organizations build human capability faster—and we're looking for people who are passionate about making a meaningful impact for customers while growing alongside a collaborative, people-first team. Litmos is the Learning Acceleration Platform that helps organizations build capability faster, adapt at the speed business changes, and scale learning to anyone, anywhere. Combining an intuitive platform, AI-powered capabilities, trusted content, expert services, and a broad ecosystem of integrations, Litmos helps organizations accelerate workforce productivity, improve customer adoption and retention, enable high-performing partners, and reduce organizational risk through continuous learning. Organizations such as Hewlett Packard Enterprise, Graco, Sabre, and Russell Mineral Equipment trust Litmos to accelerate learning across their workforce, partners, and customers. Today, more than 11K customers with 30 million learners across 150 countries and 37 languages use Litmos to build the capabilities their organizations need to succeed. Backed by Francisco Partners, one of the world's leading technology investment firms, we're investing in the future of learning—and the people who are building it. Learn more at www.litmos.com . We are looking for a Senior Full Stack Engineer to build and evolve our platform using .NET, React, and SQL Server-based systems. You will work across services, APIs, and front-end systems with a focus on scalability, reliability, and maintainability. You will operate within a globally distributed Agile team (Scrum and ShapeUp), where engineers own delivery, from design through deployment, while collaboratin

Instawork is on a mission to create meaningful economic opportunities for skilled hourly professionals in communities around the globe. Our AI-powered labor marketplace helps local businesses scale, and enables global technology companies to push the frontiers of robotics and AI. Backed by world-class investors like Benchmark, Spark Capital, Craft Ventures, Greylock, Y Combinator, and others, we’re looking for exceptional talent to reimagine the way the world works. Check out our Engineering blog here Who You Are: 5–8 years building and shipping high-traffic web or mobile apps in production. Strong coding and problem-solving skills. While experience with our stack (Python/Django, Celery, MySQL, Redis, ElasticSearch, React Native) is preferred, it's not mandatory. Proficiency in frontend technologies like React, Redux, and Responsive Design Systems. Experience in system design, distributed systems, and both relational and No-SQL databases. What You'll Do: End-to-end design, development, and deployment of high-scale web and mobile features. Prioritizing the highest ROI work—move quickly on the projects that matter most. Tackling large, complex software projects and delivering them on aggressive timelines. Maintaining peak team productivity: juggle multiple priorities in a fast-paced environment. Partnering with PMs and designers to choose the simplest, most maintainable solution. Raising the bar through thoughtful code reviews and clear technical feedback. Perks: Free snacks Health Insurance Personal Insurance Flexible Hours Maternity/Paternity Leave Broadband Reimbursement #LI-SS3 Our Values Empathy, Trust & Candor We put ourselves in the shoes of our colleagues and customers and don’t shy away from uncomfortable conversations, instead building trust through honest and direct feedback. Bias for Action We practice high-velocity decision-making, clear-eyed that we often operate with incomplete information. Growing quickly means it’s OK to be wrong, so l

This is Adyen Adyen provides payments, data, and financial products in a single solution for customers like Meta, Uber, H&M, and Microsoft - making us the financial technology platform of choice. At Adyen, everything we do is engineered for ambition. For our teams, we create an environment with opportunities for our people to succeed, backed by the culture and support to ensure they are enabled to truly own their careers. We are motivated individuals who tackle unique technical challenges at scale and solve them as a team. Together, we deliver innovative and ethical solutions that help businesses achieve their ambitions faster. Financial Products Adyen is expanding beyond payments by building an entire suite of embedded financial services tailored for platforms, marketplaces, SaaS businesses, on-demand platforms, and crowdfunding platforms. Our team’s mission is to enable these platforms to manage their global payments and financial services seamlessly through API integrations or hosted solutions. With our solutions, platforms can: Run onboarding, verification, and compliance processes across multiple markets. Manage payments and trigger faster payouts and bank transfers in all preferred currencies. Offer value-added services like capital lending and the issuing of payment cards and bank accounts. Our team is responsible for developing the technology behind this unified platform, focused on several different areas. Your role: You will build and maintain our distributed high-performance platform. You will contribute to architectural design decisions and ensure the scalability of our platform. You will help develop teammates, mentoring and coaching junior engineers and peers while maintaining a feedback loop to foster both your and their continuous growth. You will be part of a diverse and inclusive team. We launch fast and iterate often. Concretely, this means that within your first few weeks, you will bring code live that impacts many businesses and

This is Adyen Adyen provides payments, data, and financial products in a single solution for customers like Meta, Uber, H&M, and Microsoft - making us the financial technology platform of choice. At Adyen, everything we do is engineered for ambition. For our teams, we create an environment with opportunities for our people to succeed, backed by the culture and support to ensure they are enabled to truly own their careers. We are motivated individuals who tackle unique technical challenges at scale and solve them as a team. Together, we deliver innovative and ethical solutions that help businesses achieve their ambitions faster. Documentation Tooling Team The Documentation Tooling Team is responsible for building the systems and foundations that improve how technical knowledge is created, structured, and delivered across Adyen’s developer ecosystem. You will work on core challenges related to content quality, freshness, consistency, scalability and the ability to make information usable both for people and agents. In this role, you will build the next generation of Adyen’s knowledge platform. This platform turns static documentation into structured, queryable knowledge.This includes structuring content, connecting content from multiple sources and building interfaces that make technical documentation accessible across products and tools as knowledge. Your work will power reliable, contextual and efficient access to information for customers, developers, AI agents and internal teams. The team is a strategic part of the Developer Experience group within the Customer Experience solution. Our mission is to provide clear, accurate, and accessible knowledge that supports customers throughout their integration journey and helps them move quickly with confidence. Core Focus Area Content Architecture: Design scalable graph schemas, ontologies, and metadata models that support consistency, reuse, and discoverability across documentation. Serverless Pipeline Orchestra