Senior Backend Software Engineer Application Development Jobs

Senior Fullstack Software Engineer Location: Soho, NYC / Hybrid (an in-person interview may be required) Department: Engineering The Role We’re looking for a Senior Fullstack Software Engineer to help architect, build, and scale the next generation of our Flowcode 2 platform and consumer experiences. You will join our engineering team with a focus on creating amazing end user hub and landing page experiences that are dynamic and engaging, as well as the platform and management capabilities for creators on the platform. You’ll work across the stack — from contributing to backend services to building out dynamic end to end landing pages. Though this is a full stack position, we are looking for someone that has deep backend experience as well. As one of the senior engineers on a small but highly capable team, you’ll own medium to large sized features, drive technical execution, contribute to a delivery focused environment, and mentor others. You’ll balance hands-on engineering with architectural thinking, helping us move fast while maintaining reliability, performance, and code quality. This is an ideal role for a problem-solver who values simplicity over complexity, enjoys building dynamic and interactive applications and approaches engineering with pragmatism and curiosity. What You’ll Do Design, build, and maintain scalable features across a modern front-end framework and backend services. With support, own key features end-to-end, from data design to user-facing experiences. Architect for growth — help drive your pods’s technical roadmap and shepherd established engineering best practices. Collaborate across teams with product, design, and data to deliver measure, deliver and grows features quickly and iteratively. Write clean, reliable, and maintainable code, with strong attention to performance, best practices and developer experience. Mentor engineers and help elevate technical execution across you pod. Stay pragmatic — balance ideal engineering with the

We believe that the way people interact with their finances will drastically improve in the next few years. We’re dedicated to empowering this transformation by building the tools and experiences that thousands of developers use to create their own products. Plaid powers the tools millions of people rely on to live a healthier financial life. We work with thousands of companies like Venmo, SoFi, several of the Fortune 500, and many of the largest banks to make it easy for people to connect their financial accounts to the apps and services they want to use. Plaid’s network covers 12,000 financial institutions across the US, Canada, UK and Europe. Founded in 2013, the company is headquartered in San Francisco with offices in New York, Seattle, Washington D.C., Raleigh, London, and Amsterdam. Plaid’s mission is to unlock financial freedom for everyone by making money movement and access to financial data simple and secure. As a Fullstack Software Engineer, you will design and build the systems and experiences that power how millions of people connect to their finances. You will work across the stack, building scalable backend services and APIs while also crafting intuitive, high-quality frontend experiences that bring those systems to life. This role is ideal for engineers who enjoy switching between backend problem-solving and frontend user experience work, and who are excited to grow their impact across both. You will collaborate closely with product managers, designers, and other engineers to ship products that are reliable, secure, and delightful to use. At Plaid, engineers take ownership early, contribute to architectural decisions, and see their work reach millions of users. Responsibilities: Build across the stack. Design, develop, and maintain scalable backend services and APIs, as well as intuitive, high-quality frontend applications that bring those systems to life. Collaborate cross-functionally. Partner closely with product managers and designers to define

We believe that the way people interact with their finances will drastically improve in the next few years. We’re dedicated to empowering this transformation by building the tools and experiences that thousands of developers use to create their own products. Plaid powers the tools millions of people rely on to live a healthier financial life. We work with thousands of companies like Venmo, SoFi, several of the Fortune 500, and many of the largest banks to make it easy for people to connect their financial accounts to the apps and services they want to use. Plaid’s network covers 12,000 financial institutions across the US, Canada, UK and Europe. Founded in 2013, the company is headquartered in San Francisco with offices in New York, Seattle, Washington D.C., Raleigh, London, and Amsterdam. Plaid’s mission is to unlock financial freedom for everyone by making money movement and access to financial data simple and secure. As a Fullstack Software Engineer, you will design and build the systems and experiences that power how millions of people connect to their finances. You will work across the stack, building scalable backend services and APIs while also crafting intuitive, high-quality frontend experiences that bring those systems to life. This role is ideal for engineers who enjoy switching between backend problem-solving and frontend user experience work, and who are excited to grow their impact across both. You will collaborate closely with product managers, designers, and other engineers to ship products that are reliable, secure, and delightful to use. At Plaid, engineers take ownership early, contribute to architectural decisions, and see their work reach millions of users. Responsibilities: Build across the stack. Design, develop, and maintain scalable backend services and APIs, as well as intuitive, high-quality frontend applications that bring those systems to life. Collaborate cross-functionally. Partner closely with product managers and designers to define

OKX will be prioritising applicants who have a current right to work in Singapore, and do not require OKX's sponsorship of a visa About OKX At OKX, we believe that the future will be reshaped by crypto, and ultimately contribute to every individual's freedom. OKX is a leading crypto exchange, and the developer of OKX Wallet, giving millions access to crypto trading and decentralized crypto applications (dApps). OKX is also a trusted brand by hundreds of large institutions seeking access to crypto markets. We are safe and reliable, backed by our Proof of Reserves. Across our multiple offices globally, we are united by our core principles: We Before Me, Do the Right Thing, and Get Things Done. These shared values drive our culture, shape our processes, and foster a friendly, rewarding, and diverse environment for every OK-er. OKX is part of OKG, a group that brings the value of Blockchain to users around the world, through our leading products OKX, OKX Wallet, OKLink and more. About the Opportunity Join our Retail Trading team and you will be working alongside a high-performing team to deliver comprehensive and timely market information to millions of retail users. You will leverage your expertise to design and build easy-to-use applications with distinguishable precision, speed, and insights. In this role, you’ll also contribute to the evolution of our architectural foundations, ensuring that our solutions remain reliable, scalable, and adaptable in a rapidly evolving market. What You’ll Be Doing Design, develop, and maintain high-quality backend systems for market analysis in a fast-paced, dynamic environment. Collaborate closely with product managers, frontend engineers, and infrastructure teams to deliver scalable and efficient solutions. Continuously improve system reliability, scalability, and maintainability through thoughtful design and engineering best practices. Actively participate in code reviews, architecture design discussion

Distributed Systems engineers at Datadog design, implement and run in production the foundational platforms powering our applications. Your data pipelines will ingest, store, analyze and query in real-time billions of events per second from companies all over the globe. The platforms are optimized for durability, high availability, low latency, internet-scale footprint and operability. At Datadog, we place value in our office culture - the relationships that it builds, the creativity it brings to the table, and the collaboration of being together. We operate as a hybrid workplace to ensure our employees can create a work-life harmony that best fits them. What You’ll Do: Build fault-tolerant, horizontally scalable solutions running in multi-tenant environments Write in Go, Java, Rust or C++, amongst other languages Use Kafka, Redis, Cassandra, Elasticsearch and other open-source components Own meaningful parts of our service, have an impact, grow with the company Who You Are: You have a BS/MS/PhD in a scientific field or equivalent experience You have significant backend programming experience in one or more languages (Go, Java, Rust, C++) You have been exposed to working on problems (high durability / low latency /…) You can get down to the low-level when needed You care about simple designs and performance You want to work in a fast, high-growth startup environment that respects its engineers and customers You’re excited about leveraging AI tools to enhance how you code, solve problems, and build – or eager to learn how You have demonstrated ability to use AI coding tools in day-to-day workflows and validate, critique, and refine AI-generated output Bonus: You’re motivated to push the boundaries of how AI can improve software engineering best practices and contribute to building AI-enabled products Datadog values people from all walks of life. We understand not everyone will meet all the above qualifications on day one. That's okay. If you

Distributed Systems engineers at Datadog design, implement and run in production the foundational platforms powering our applications. Your data pipelines will ingest, store, analyze and query in real-time billions of events per second from companies all over the globe. The platforms are optimized for durability, high availability, low latency, internet-scale footprint and operability. At Datadog, we place value in our office culture - the relationships that it builds, the creativity it brings to the table, and the collaboration of being together. We operate as a hybrid workplace to ensure our employees can create a work-life harmony that best fits them. What You’ll Do: Build fault-tolerant, horizontally scalable solutions running in multi-tenant environments Write in Go, Java Rust or C++, amongst other languages Use Kafka, Redis, Cassandra, Elasticsearch and other open-source components Own meaningful parts of our service, have an impact, grow with the company Who You Are: 6+ years of experience You have a BS/MS/PhD in a scientific field or equivalent experience You have significant backend programming experience in one or more languages (Go, Java, Rust, C++) You have been exposed to working on problems (high durability / low latency /…) You can get down to the low-level when needed You care about simple designs and performance You want to work in a fast, high-growth startup environment that respects its engineers and customers You have demonstrated ability to use AI coding tools in day-to-day workflows and validate, critique, and refine AI-generated output. Bonus: you’re motivated to push the boundaries of how AI can improve software engineering best practices and contribute to building AI-enabled products. This job is available in various departments within our company; to conform to US export control regulations, some of these roles may require candidates to be eligible for any required authorizations from the US government. Datadog values peo

Why Sony Interactive Entertainment? Sony Interactive Entertainment isn’t just the Best Place to Play — it’s also the Best Place to Work. Sony Interactive Entertainment (SIE) is the company behind the PlayStation brand. As a subsidiary of Sony Group Corporation, we’re part of a proud legacy of innovation and excellence. SIE is a dynamic technology company, delivering cutting-edge hardware and network services to more than 100 million people and an entertainment leader, home to some of the most beloved and recognizable intellectual properties (IP) in the world. Our role at SIE is to create and nurture the experiences under the PlayStation brand, a name synonymous with entertainment excellence and creativity. Senior Software Engineer - AI & Agentic Architecture This is a senior individual-contributor role combining deep hands-on engineering with multiple agentic frameworks & SDKs, harnesses, MCP, and APIs, technical leadership, and close collaboration with engineering, security, and product teams. You'll design and ship agentic systems, developer tooling, and reusable platform capabilities that improve productivity across SIE. What you'll do: Agentic & AI Engineering Design, build, and operate production-quality agentic applications using agentic SDKs/harnesses — including multi-agent orchestration, subagent delegation, tool integration, and lifecycle hooks. Design Model Context Protocol (MCP) tool and resource interfaces that give coding agents/harnesses safe, reliable access to backend systems and enterprise data. Engineer prompts for reliable structured output (JSON schemas, few-shot examples, validation/retry loops) and build evaluation frameworks to measure and improve output quality. Manage context effectively across long documents, multi-turn conversations, and multi-agent handoffs; design escalation and human-in-the-loop patterns for production reliability. Developer Productivity Configure and extend Codex/Claude Code for team-wide use: AGENT

We are a global team of innovators and pioneers dedicated to shaping the future of observability. At New Relic, we build an intelligent platform that empowers companies to thrive in an AI-first world by giving them unparalleled insight into their complex systems. As we continue to expand our global footprint, we're looking for passionate people to join our mission. If you're ready to help the world's best companies optimize their digital applications, we invite you to explore a career with us! Your opportunity We are a global team of innovators shaping the future of observability. Our intelligent platform gives customers real-time insight into complex systems so they can innovate faster and operate reliably in an AI-first world. If you’re excited by high-throughput distributed systems and want to contribute to one of the largest and fastest-growing observability platforms, we’d love to hear from you. Join a backend engineering team focused on building and operating JVM-based services that ingest, process, and serve massive volumes of telemetry data. You’ll work on high-scale, low-latency systems that power mission-critical observability features used by engineers worldwide. What you'll do Design, build, and operate JVM-based microservices (primarily Java and Kotlin) with a focus on performance, scalability, and reliability. Own services end-to-end: architecture, implementation, deployment, monitoring, on-call participation, and continuous improvement. Apply strong concurrency and performance practices: asynchronous programming, backpressure, efficient I/O, memory management, and GC tuning. Build and evolve event-driven systems; work with Kafka for streaming, partitioning, consumer groups, and schema evolution.Instrument services for deep observability (metrics, logs, traces), define SLIs/SLOs, and use e Experience with Kafka or similar streaming technologies (topic/partition strategy, consumer lag, idempotency, schema compatibility) strongly preferred. Proficiency w

Scale’s rapidly growing Global Public Sector team is focused on using AI to address critical challenges facing the public sector around the world. Our core work consists of: Creating custom AI applications that will impact millions of citizens Generating high-quality training data for custom LLMs Upskilling and advisory services to spread the impact of AI As a Full Stack Software Engineer (Forward Deployed), you’ll collaborate directly with public sector counterparts to quickly build full-stack, AI applications, to solve their most pressing challenges and achieve meaningful impact for citizens. At Scale, we’re not just building AI solutions—we’re enabling the public sector to transform their operations and better serve citizens through cutting-edge technology. If you’re ready to shape the future of AI in the public sector and be a founding member of our team, we’d love to hear from you. You will: Partner with public sector clients to scope, collect feedback and implement solutions for complex problems, including spending up to two weeks per month in client offices for feedback and delivery. Architect production-grade applications that integrate AI models with full-stack frameworks, managing everything from interactive UIs to backend APIs and systems. Deploy and manage infrastructure within cloud environments, ensuring the highest levels of system integrity, security, scalability, and long-term reliability. Contribute to core platform features designed to be reused across diverse international client use cases. Partner with design, product, and data teams to build robust applications aligned with the broader technical architecture. Ideally you’d have: Bachelor’s degree in Computer Science or a related quantitative field 5+ years of post-graduation, full-stack engineering experience with demonstrated proficiency in React (required), TypeScript, Next.js, Python, Node.js, PostgreSQL or MongoDB plus hands-on experience with Docker, Kubernetes, and Azure

Senior Software Engineer – Security & Distributed Systems Location: United States — Remote Department: Engineering Company: RapidFort Employment Type: Full-Time U.S. Citizenship: Required About RapidFort RapidFort is a cybersecurity company focused on securing and optimizing modern software supply chains and cloud-native environments. Our technology helps organizations reduce software vulnerabilities and attack surface by identifying and removing unnecessary components from containerized applications. RapidFort works with enterprise and U.S. public-sector customers operating highly complex, security-sensitive environments. We are building systems that operate at the intersection of cybersecurity, distributed systems, Linux, containers, Kubernetes, and cloud infrastructure . The Role RapidFort is looking for a Senior Software Engineer – Security & Distributed Systems to join our engineering team. This is a hands-on backend engineering role for someone who enjoys solving complex systems problems and building production software that operates across distributed, containerized environments. You will design and develop backend services and distributed systems that power RapidFort’s security platform, working with large volumes of software, vulnerability, container, and runtime data. This is not an SRE or infrastructure operations position . We are looking for a software engineer who builds systems and products, with strong knowledge of the infrastructure and environments in which those systems operate. What You’ll Do Design, build, and maintain highly reliable backend services and distributed systems. Develop core components of RapidFort’s cybersecurity and software supply chain security platform. Build systems for processing, analyzing, and managing large volumes of security, vulnerability, package, container, and runtime data. Design scalable APIs, services, data pipelines, and internal platform components. Develop software that operates across Linux, container

Location(s): US (remote), Boston (hybrid), or New York (hybrid) Who We Are Toast is driven by building the restaurant platform that helps restaurants adapt, take control, and get back to what they do best: building the businesses they love. We are looking for a Staff Software Engineer to join the Voice AI Team. On the Voice AI Team, our mission is to build and operate the voice platform that powers Toast and to ship novel applications on top of it that create real value across Toast's customer base. This is a greenfield space where the platform and its use cases are being defined together, and the work you do here will be foundational to how Toast uses voice AI for years to come. As a Software Engineer on this team, you'll take ownership of significant projects end-to-end: designing systems, driving execution across the team, and making the technical decisions that shape how the platform grows. You'll work closely with product, engineering, and stakeholders across Toast to turn ambiguous problems into reliable, scalable systems. About this roll* (Responsibilities) Design, build, deploy, and maintain highly resilient and scalable backend services, applications, and core platform components supporting Toast's Voice AI platform used across teams Conceive and lead complex, cross-cutting projects from design through production, owning outcomes and driving alignment across stakeholders and across a broad range of stakeholders Shape the technical direction on your team and beyond by making architectural decisions, defining patterns, and reducing complexity for the engineers and teams that depend on your work Build and evolve integrations with AI platforms and internal Toast systems, making pragmatic tradeoffs between speed, reliability, and long-term scalability Establish and implement patterns for observability, monitoring, and evaluation frameworks for AI-powered systems, using production data to understand and continuously improve system behavior Set a

Meet Yubico Yubico is a global leader in identity security and creator of the YubiKey, the original hardware-backed passkey. We are publicly traded on Nasdaq Stockholm; our global footprint includes headquarters in Stockholm, Sweden, Silicon Valley, California; and Singapore. Why Join Our Mission? At Yubico, we are guided by a shared belief that your work matters. We operate under a cultural philosophy of Speed with Integrity , pushing the boundaries of technology to secure the AI frontier—protecting both human and agentic AI interactions—and leading the transition to post-quantum cryptography. In everything we do, we live by our core values: Battle Friction: We constantly look for new ways to simplify our products, our work, and the user experience. Inspire Higher: We think big, champion the open internet, and strive to do the right thing even when it is difficult. One Team: We are open, responsive, and collaborative, overcoming challenges and celebrating our successes together. Aligned with our commitment to open standards, we foster a thriving builder ecosystem through the Yubico Developer Program , offering free open-source repositories , libraries, and SDKs to help developers rapidly integrate strong hardware authentication into any application. Through close collaborations with technical partners like Google, Microsoft, and Amazon, as well as newer frontiers like OpenAI, we continue to shape a safer digital world while donating security keys to protect vulnerable communities, journalists, and humanitarian groups worldwide through our Secure it Forward program. At Yubico, We Offer Yubico Values: We work to ensure that our employees have an open space to have their voices amplified to create a workplace where everyone feels like they belong. In support of this, our employees have created some pretty cool Employee Resource Groups that foster inclusion, help build community and connection across Yubico which all employees are welcome to join. Additionally, Yubico

Salary Range: PLN 260,000-352,000 Subject to alignment to the responsibilities and duties of the role About Graphcore At Graphcore, we’re building the future of AI compute. We’re a team of semiconductor, software and AI experts, with deep experience in creating the complete AI compute stack - from silicon and software to infrastructure at datacenter scale. As part of the SoftBank Group, backed by significant long-term investment, we are delivering key technology into the fast-growing SoftBank AI ecosystem. To meet the vast and exciting AI opportunity, Graphcore is expanding its teams around the world. We are bringing together the brightest minds to solve the toughest problems, in a place where everyone has the opportunity to make an impact on the company, our products and the future of artificial intelligence Job Summary We are looking for a senior engineer to design and evolve an application-level simulator for ML workloads that directly influences hardware and software architecture decisions. This role sits at the intersection of machine learning, systems, and hardware design. You will model real-world workloads, predict system behaviour, and provide insights that guide how our platform evolves. Success in this role requires not only strong technical depth, but also the ability to work closely with multiple teams to ensure the simulator reflects reality and drives meaningful decisions. The Team The Tenjin team focuses on building advanced simulation capabilities to model and predict the behaviour of large-scale ML workloads on next-generation hardware and software platforms. We operate at the intersection of machine learning, systems, and architecture, developing tools that enable data-driven decisions long before systems are fully built or deployed. Our work helps shape both hardware and software direction by providing early insights into performance, scalability, and efficiency. The team brings together engineers with backgrounds in simu

Scale’s rapidly growing Global Public Sector team is focused on using AI to address critical challenges facing the public sector around the world. Our core work consists of: Creating custom AI applications that will impact millions of citizens Generating high-quality training data for custom LLMs Upskilling and advisory services to spread the impact of AI As a Full Stack Software Engineer (Forward Deployed), you’ll collaborate directly with public sector counterparts to quickly build full-stack, AI applications, to solve their most pressing challenges and achieve meaningful impact for citizens. At Scale, we’re not just building AI solutions—we’re enabling the public sector to transform their operations and better serve citizens through cutting-edge technology. If you’re ready to shape the future of AI in the public sector and be a founding member of our team, we’d love to hear from you. You will: Partner with public sector clients to scope, collect feedback and implement solutions for complex problems, including spending up to two weeks per month in client offices for feedback and delivery. Architect production-grade applications that integrate AI models with full-stack frameworks, managing everything from interactive UIs to backend APIs and systems. Deploy and manage infrastructure within cloud environments, ensuring the highest levels of system integrity, security, scalability, and long-term reliability. Contribute to core platform features designed to be reused across diverse international client use cases. Partner with design, product, and data teams to build robust applications aligned with the broader technical architecture. Ideally you’d have: Bachelor’s degree in Computer Science or a related quantitative field 5+ years of post-graduation, full-stack engineering experience with demonstrated proficiency in React (required), TypeScript, Next.js, Python, Node.js, PostgreSQL or MongoDB plus hands-on experience with Docker, Kubernetes, and Azure

Scale’s rapidly growing Global Public Sector team is focused on using AI to address critical challenges facing the public sector around the world. Our core work consists of: Creating custom AI applications that will impact millions of citizens Generating high-quality training data for custom LLMs Upskilling and advisory services to spread the impact of AI As a Full Stack Software Engineer (Forward Deployed), you’ll collaborate directly with public sector counterparts to quickly build full-stack, AI applications, to solve their most pressing challenges and achieve meaningful impact for citizens. At Scale, we’re not just building AI solutions—we’re enabling the public sector to transform their operations and better serve citizens through cutting-edge technology. If you’re ready to shape the future of AI in the public sector and be a founding member of our team, we’d love to hear from you. You will: Partner with public sector clients to scope, collect feedback and implement solutions for complex problems. Architect production-grade applications that integrate AI models with full-stack frameworks, managing everything from interactive UIs to backend APIs and systems. Deploy and manage infrastructure within cloud environments, ensuring the highest levels of system integrity, security, scalability, and long-term reliability. Contribute to core platform features designed to be reused across diverse international client use cases. Partner with design, product, and data teams to build robust applications aligned with the broader technical architecture. Ideally you’d have: Bachelor’s degree in Computer Science or a related quantitative field 5+ years of post-graduation, full-stack engineering experience with demonstrated proficiency in React (required), TypeScript, Next.js, Python, Node.js, PostgreSQL or MongoDB plus hands-on experience with Docker, Kubernetes, and Azure/AWS/GCP. Proven ability to architect scalable, production-grade applications with a stron