Senior Backend Software Engineer Application Development Jobs

Senior Software Engineer, Backend — Toast International Location: Toronto, ON / Canada Hybrid (Ontario) 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. Are you bready* for a change? As a Senior Backend Engineer on the Toast International team, you’ll play a pivotal role in engineering the platform that powers the next generation of guest reservations, dynamic floor management, and table operations across global markets like the UK, Europe, and Canada. You will lead the design and execution of core backend services—building scalable backend systems, robust integrations, data processing pipelines, and core platform capabilities. You’ll collaborate closely with engineering teams in North America and Europe, product managers, and designers to win high-value full-service restaurants worldwide. About this roll* (Responsibilities) Architect, implement, and scale distributed backend microservices (Java / Kotlin / AWS) powering reservations and guest management. Build core transactional and payment capabilities for the platform. Design robust integrations with third-party aggregators and partners and two-way POS synchronization. Implement tiering, entitlements, and usage metering services across freemium waitlists and premium subscription tiers. Partner cross-functionally with Mobile, Web/Frontend, Product Management, and UX to deliver seamless end-to-end features. Drive high standards of code quality, observability, test automation (unit, integration, and contract tests), and operational excellence. Mentor team members, participate in technical design reviews, and leverage modern AI development workflows to accelerate velocity and code quality. Do you have the right ingredients*? (Requirements) 5+ years of software engineering experience building scalable, distributed backend microservices in production. Deep proficiency in Java or Kot

Why Harvey At Harvey, we’re transforming how legal and professional services operate. By combining frontier agentic AI, an enterprise-grade platform, and deep domain expertise, we’re reshaping how critical knowledge work gets done for decades to come. This is a rare chance to help build a generational company at a true inflection point. We have strong product-market fit and world-class investor support. We’re scaling fast and defining a new category in real time. The work is ambitious, the bar is high, and the opportunity for growth — personal, professional, and financial — is unmatched. Our team moves fast, takes ownership, and is deeply committed to the mission — operating with intensity, staying close to our customers, and pushing each other for excellence. We live by three values: Decisiveness, Simplicity, and Job's Not Finished. We act quickly on clear judgment over perfect information, we believe simplicity is what scales, and we're never satisfied with where we are. If you want to do the best work of your career alongside people who share that drive, we'd love to build with you. At Harvey, the future of professional services is being written today — and we’re just getting started. Role Overview As a Backend Software Engineer at Harvey, you’ll play a pivotal role in constructing the foundation of our product platform while directly building user-facing features for some of the world’s leading law firms and enterprise customers. This team owns and operates the platform layer that enables secure, reliable, and flexible experiences for our customers including notifications, permissions and feature flag infrastructure. We also build enterprise-grade collaboration experiences for law firms. You will design systems that not only serve as critical infrastructure for the rest of the company, but also directly impact how our users engage with Harvey’s AI-powered legal tools. This role is ideal for engineers who are excited by the opportunity to move between deep platfo

About Us: Perpay is a certified B Corp and Philadelphia’s most impactful growth-stage startup. We are driven by a mission to significantly improve the financial stability of everyday Americans. For the past decade, we have established strong product-market fit and a profitable, efficient operating model across a suite of products, positioning Perpay as the premier financial partner for consumers with subprime credit. With over 500,000 customers who have utilized more than $1 billion in spending power, we are at a pivotal moment. We are scaling our operations, building new offerings, and deepening our impact. We are looking for teammates eager to join us on this journey. Our venture partners include First Round Capital and L Catterton. Products we’ve built to make an impact: Perpay Marketplace: Combines interest-free payments and modern e-commerce to reduce cost of ownership and promote healthy repayment behavior. Perpay+: Leverages Marketplace repayment history to help members monitor and build credit with all 3 credit bureaus. Perpay Credit Card: Expands access to the flexibility and benefits of a World Mastercard by removing common barriers like high security deposits and low approval odds. Our team thrives on in-person collaboration, operating from our unique center-city Philadelphia office. This comfortable "home away from home" space offers river views and fosters rapid product development, strong relationships, and career growth. The energy from achieving big wins is palpable here. While we primarily work in the office, we offer sensible flexibility for personal needs, such as sick children or urgent errands, and coordinate official remote weeks around major holidays. If you are passionate about a meaningful mission, collaboration, equity, and generous perks, Perpay is the best place to be in Philadelphia right now. About the Role: We are looking for senior backend engineers passionate about backend technology, excellent user experience and system reliability.

About Appier Appier is an AI-native Agentic AI as a Service (AaaS) company that uses artificial intelligence (AI) to power business decision-making. Founded in 2012 with a vision of democratizing AI, Appier’s mission is turning AI into ROI by making software intelligent. Appier now has 17 offices across APAC, Europe and U.S., and is listed on the Tokyo Stock Exchange (Ticker number: 4180). Visit www.appier.com for more information. About the role Appier's Playable Ads team ( https://www.appier.com/en/blog/what-is-playable-ads ) builds AI-powered playable and video ad experiences that drive dramatically higher engagement and conversion for the world's leading apps and games. We're looking for a Senior Backend Developer with deep expertise in distributed systems and modern backend architecture to design and build the scalable, high-performance services behind these experiences — from creative generation pipelines to the infrastructure that brings our ML models to production. You'll work across microservices, messaging systems, data persistence layers, and system performance optimization, while partnering with ML scientists on MLOps workflows to continuously ship and serve new model versions to end users. You'll also collaborate closely with frontend engineers and product managers to deliver seamless, cross-functional outcomes. If you're passionate about building backend systems that operate at scale, thrive in cross-functional teams, and want your code to directly power AI-driven ad experiences reaching millions of users, we'd love to talk. What You'll Work On Architect and develop robust, scalable backend services and APIs using ASP.NET Core, owning sizable projects from system design through production operation. Design efficient database schemas and optimize data access logic across SQL and NoSQL data stores. Implement message-driven communication with high reliability and fault tolerance. Partner with ML scientists to build and maint

About Appier Appier (TSE: 4180) is an AI-native Agentic AI as a Service (AaaS) company that empowers businesses to create value through cutting-edge AdTech and MarTech solutions. Founded in 2012 with the vision of “Making AI Easy by Making Software Intelligent,” Appier helps businesses turn AI into ROI through its Ad Cloud, Personalization Cloud, and Data Cloud—each powered by Agentic AI that enables autonomous, adaptive, and real-time decision-making. Today, Appier operates 17 offices across APAC, the US, and EMEA, and is listed on the Tokyo Stock Exchange. Learn more at www.appier.com . About the role Software engineers at Appier build a wide range of platforms and services that interconnect data and AI with our customers and users. As a Senior Software Engineer, Backend Development at Ad Cloud Platform Team , you will design and build scalable and performant backend architecture, own and drive the technical roadmap for sizable projects or services, mentor junior engineers, and facilitate high performance agile teams collaborating with cross-functional teams. About you [Minimum Qualifications] 2~4 years of hands-on experience in backend software development, particularly with high-performance, high-concurrency systems. Proficient in one or more of the following languages, Python is preferred. Strong experience in system design and architecture for scalable and distributed systems, especially within a Linux environment. Good understanding of Network API Design (e.g., RESTful APIs, gRPC, GraphQL) and experience with message queues (e.g., Kafka, Pub/Sub) for data pipelines. Solid knowledge of SQL/NoSQL databases (e.g., MySQL, MongoDB, Redis, ClickHouse, PostgreSQL) and experience with database optimization and scaling strategies. Familiarity with DevOps practices, including CI/CD pipelines, Docker, Kubernetes, and cloud platforms (AWS, GCP, or Azure). Experience with observability tools (e.g., Prometheus, Grafana) and ro

This is a core backend software engineering role (70% SWE / 30% Data) within our Mapping organization. You will focus primarily on building high-throughput services, distributed system architecture, and APIs, while leveraging large-scale spatial data to power Lyft's routing and mapping products. Note: This position focuses on backend service architecture and platform scalability rather than traditional ETL, BI, or data modeling pipelines. At Lyft, our purpose is to serve and connect. We aim to achieve this by cultivating a work environment where all team members belong and have the opportunity to thrive. As a Senior Software Engineer, Data on the Mapping team, you will collaborate with our world-class team of engineers, product managers, and scientists to grow and improve the quality of recommended routes and accuracy of our travel time estimations. You will lead the architecture and long-term technical direction of our offline experimentation tooling and route simulation services — the systems that let Lyft test routing changes safely before they reach production. You'll also build scalable data pipelines for experimentation, analytics, and machine learning models, along with the data governance and observability systems that keep them trustworthy. Your work will enable integration with partner teams and allow stakeholders across Engineering, Data Science, and Product to make data-informed decisions that directly impact Lyft’s growth and profitability. Our technology stack is based on the latest technologies such as AWS, Databricks, Kubernetes and Airflow. You will work with incredibly passionate and talented colleagues from software engineering, machine learning and data science on projects that directly impact millions of riders and drivers. Responsibilities Own core data pipelines end-to-end, building deep subject matter expertise in the systems you manage and defining/managing SLAs for pipelines, services, and datasets to ensure reliability at scale Serv

About Us The Rubrik Security Apps team helps customers secure their data on the cloud. Cloud data is growing at an ever growing pace and so are the risks with cyber attacks targeted towards cloud data. We make it easy for businesses to protect, search, analyze all of their cloud data simply and scalably. Security Apps is one of the fastest growing businesses and teams within Rubrik. We consider ourselves a startup inside a startup! Join us in this journey where there are ever widening avenues to explore, opportunities to innovate, deep engineering problems to tackle. We believe in fostering a culture with strong engineering values and teamwork as the key to building a great company and product. When you become part of our dynamic and innovative team, you'll contribute to the development of cutting-edge products within a fast-growing company that prides itself on an exceptional culture and a dynamic work environment. About the Role We're looking for a Senior Backend Engineer to join our R&D team. You will work closely with our product team to build our unique product offering. As a Senior Backend Engineer, you will be responsible for building complex backend designs that are both scalable and fault-tolerant, developing our data ingestion pipeline and introducing new analysis engines. What You'll Be Doing Design, develop, test, deploy, maintain and improve the software. You’ll have your domain of expertise in which you'll assist the product team with future directions, lead the technology and cooperate with other engineers. You’ll develop backend services that integrate with and ingest data from various cloud providers that store sensitive data. You’ll build pipelines that analyze, classify, correlate and process this data. You’ll build systems that detect anomalies in the ingested data for alerting the customer, that automatically resolve issues and that generate sophisticated yet easily consumable insights arising from the processed dat

As a Senior Backend Engineer on Coder's Enterprise Experience team, you'll build the systems that help large organizations run Coder in production with confidence. You'll improve how Coder scales, how it's upgraded, and how reliably it performs in regulated, air-gapped, and enterprise environments. You'll work on a genuinely cross-functional team of backend, platform, and QA engineers who own the end-to-end experience for Coder operators. From designing new features to evolving Coder's architecture, you'll partner across engineering and product to solve complex problems and ship software that operators trust. What you'll do here Design and build new features end to end, from technical design through production rollout. Design and implement backend architecture changes that support Coder's long-term scalability goals. Investigate and resolve scalability bottlenecks under production-like load, from database access patterns to concurrency handling in coderd. Improve database migration safety and upgrade reliability through schema compatibility, background migrations, and safe rollback strategies. Own the backend side of issues surfaced by Coder operators and administrators. Document the design, implementation, and operational tradeoffs of the systems you build. Participate in code reviews, RFC-style design discussions, and on-call rotations for the services you own. What we're looking for 5+ years of professional software engineering experience, including significant production experience with Go. Deep understanding of Go's concurrency model, including goroutines, channels, the sync package, and debugging race conditions under real-world load. Experience designing and operating relational databases in production, including schema design, migrations, and transactions. Strong verbal and written communication skills. Exceptional debugging and troubleshooting skills, with the persistence to drive complex problems to resolution. A self-motivated, analytical engineer who enj

As a Senior Backend Engineer on Coder's Enterprise Experience team, you'll build the systems that help large organizations run Coder in production with confidence. You'll improve how Coder scales, how it's upgraded, and how reliably it performs in regulated, air-gapped, and enterprise environments. You'll work on a genuinely cross-functional team of backend, platform, and QA engineers who own the end-to-end experience for Coder operators. From designing new features to evolving Coder's architecture, you'll partner across engineering and product to solve complex problems and ship software that operators trust. What you'll do here Design and build new features end to end, from technical design through production rollout. Design and implement backend architecture changes that support Coder's long-term scalability goals. Investigate and resolve scalability bottlenecks under production-like load, from database access patterns to concurrency handling in coderd. Improve database migration safety and upgrade reliability through schema compatibility, background migrations, and safe rollback strategies. Own the backend side of issues surfaced by Coder operators and administrators. Document the design, implementation, and operational tradeoffs of the systems you build. Participate in code reviews, RFC-style design discussions, and on-call rotations for the services you own. What we're looking for 5+ years of professional software engineering experience, including significant production experience with Go. Deep understanding of Go's concurrency model, including goroutines, channels, the sync package, and debugging race conditions under real-world load. Experience designing and operating relational databases in production, including schema design, migrations, and transactions. Strong verbal and written communication skills. Exceptional debugging and troubleshooting skills, with the persistence to drive complex problems to resolution. A self-motivated, analytical engineer who enj

About Us OpenFX is on a mission to move money as freely as data, unrestricted by time zones, banking hours, or legacy systems. We are building the infrastructure that will power the next generation of cross-border payment systems for institutions. The team's execution has been exceptional, and we're scaling at a remarkable pace. Our stellar early team comes with experience in companies like J.P. Morgan, Goldman Sachs, FalconX, PayPal, Affirm, Polygon, Kraken, Nium & others. We're backed by Accel, Lightspeed, NfX and other top-tier investors. Role Overview We're hiring a Staff Software Engineer for our Payments team. This is the senior-most individual contributor role on the systems that move money across borders — payment orchestration, corridor and partner integrations, FX and quoting, the payment lifecycle from initiation to settlement confirmation, and the regulated controls (safeguarding, transaction monitoring) that our EU licenses demand. It is a hands-on technical leadership role on the money path, where a new corridor is only as good as its failure handling, and a regulatory control is only as good as the evidence it produces. The cost of a defect is measured in real money, stuck customer payments, or a finding from a regulator. You will report to an Engineering Manager and work closely with engineers, product, compliance, and partnerships across the company. You will set the technical direction for payments, lead the hardest corridor and orchestration problems, and raise the bar for how we build. This role requires someone who has built and operated payment or other correctness-critical systems in production, ideally against external partners whose behavior you do not control. If your experience is limited to systems where occasional data inconsistency is acceptable, where every dependency was internal and well-behaved, or where you have not owned something end to end for a meaningful stretch, this will be a stretch. Key Responsibilities Own the technic

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 The DAP Repository Flows team owns two areas within GitLab's Duo Agent Platform (DAP). The first is DAP onboarding , helping customers quickly set up a project so they can start using the Duo Agent Platform with minimal friction. The second is repository and background flows : autonomous and scheduled agents that work on a customer's codebase on their behalf. This work is central to how GitLab delivers AI-powered automation on repositories. As a Senior Software Engineer, you will own features end to end, from design through delivery, building agentic experiences on top of the Duo Agent Platform. Wh

About the Role Together AI is building the AI Acceleration Cloud, an end-to-end platform for the full generative AI lifecycle, combining the fastest LLM inference engine with state-of-the-art AI cloud infrastructure. As a Senior Backend Engineer, you will play a key role in building the next generation AI cloud platform – a highly available, global, blazing-fast cloud infrastructure that virtualizes cutting-edge ML hardware (GB200s/GB300s, BlueField DPUs) and enables state-of-the-art ML practitioners with self-serve AI cloud services, such as on-demand + managed Kubernetes and Slurm clusters. This platform serves both our internal StaaS products (inference, fine-tuning) and our external cloud customers, spanning dozens of data centers across the world. Some of what you’ll work on: Work on a distributed GPU scheduling system for the on-demand clusters product, Instant Clusters. Build out a global management plane for managing our data center compute, networking, and storage. Design and build new customer-facing cloud platform services, delivering killer enterprise AI cloud features. Responsibilities Identify, design, and develop foundational backend services that power Together’s cloud platform Analyze and improve the robustness and scalability of existing distributed systems, APIs, databases, and infrastructure Partner with product teams to understand functional requirements and deliver solutions that meet business needs Write clear, well-tested, and maintainable software and IaC for both new and existing systems Conduct design and code reviews, create developer documentation, and develop testing strategies for robustness and fault tolerance Participate in an on-call rotation to address critical incidents when necessary Requirements 5+ years of demonstrated experience in building large scale, fault tolerant, distributed systems and API microservices Experience designing, analyzing and improving efficiency, scalability, and stability of various system resources Excel

At Lyft, our purpose is to serve and connect. We aim to achieve this by cultivating a work environment where all team members belong and have the opportunity to thrive. The Trust & Safety function at Lyft is dedicated to keeping every Lyft ride safe for both riders and drivers. We build and maintain the tools, features, and systems that deter bad actors, protect vulnerable populations, and reinforce trust across the platform. As an Backend Engineer working on Trust & Safety, you'll work at the intersection of product, design, engineering, and policy to ship high-impact safety features to millions of users. Responsibilities: Help define the roadmap and architecture based on technology and business needs Unblock, support, effectively communicate, and obtain buy-in across teams to achieve results Lead projects of multiple people from idea to positive execution Write clear, scalable and clear design documentation Write well-crafted, well-tested, readable, maintainable code Utilize your expertise in Python, Golang, AWS to deliver robust and scalable solutions Participate in code reviews to ensure code quality and distribute knowledge Proactively participate in resolving ongoing incidents Share your knowledge through tech talks, mentorship, and evangelizing appropriate tech and engineering best practices Experience: BS/MS or equivalent in Computer Engineering, Computer Science, or related field or relevant work experience 5+ years of software engineering industry experience Extensive experience in object oriented programming, ideally in GoLang or Python Experience in backend software development of large-scale distributed systems and concurrency Experience working with public cloud platforms (e.g., AWS, GCP, Microsoft Azure, etc.) Strong oral and written communication skills, and ability to collaborate with and influence cross-functional partners Benefits: Extended health and dental coverage options, along with life insurance and disability benefits Mental health

About Us What if your work could drive change in a globally established industry, shaping processes that touch every corner of the world? At Forto, we are at the forefront of change, harnessing the power of AI to revolutionise logistics. We want to reinvent digital supply chains to be transparent, frictionless and sustainable. From day one, our mission has been to simplify global trade – creating a seamless and efficient logistics process. Your role & Mission As a Senior Backend Engineer in our Shipment team, you will build the "brain" behind our logistics operations. You’ll maintain and evolve a sophisticated event-driven architecture designed to answer one crucial question: "How do we move this shipment most efficiently?" From contract rate management to automated shipment nomination, you will lead the charge in creating reliable, data-heavy systems that optimize our global portfolio. You aren’t just writing code; you’re building a revenue-driving engine. Working alongside industry experts, you will mentor your team to deliver robust services that enable NVOCCs to thrive. If you are passionate about leading teams to solve massive logistical challenges, we want to hear from you. What you will do Design and implement robust backend services for capturing, storing, and validating procurement contract rates and allotment volumes, ensuring 100% data integrity for our supply chain logic. Lead the evolution of our event-driven microservices to process high-velocity data, enabling real-time updates on contract utilization and space availability. Refactor and optimize existing systems responsible for shipment-to-contract matching to ensure low-latency performance and high maintainability. Build and iterate on the logic that answers "Which contract should we use?" by automating the nomination process based on cost, volume commitments, and carrier performance. Streamline the ingestion and management of complex carrier agreements, moving from manual entry toward a fully a

Senior Backend Engineer (Python / Go) Overview We are seeking a skilled and passionate Senior Backend Engineer to join our team, focusing on the design, development, and maintenance of high-performance, scalable microservices. The ideal candidate will have strong expertise in Go (Golang), and a deep understanding of distributed systems architecture. Essential Qualifications Technical Skills Skill Category Requirement Proficiency Level Programming Languages Python (Deep expertise with frameworks like FastAPI, Flask, or Django) Advanced Programming Languages Go (Golang) (Experience building robust, high-concurrency microservices) Expert Microservices / Architecture Designing, developing, and deploying RESTful APIs Expert Security Keycloak, API authentication, JWT Advanced Databases Realtime analytics (Clickhouse) Advanced Databases Relational databases (MySQL) including complex query optimization Advanced Databases NoSQL databases (Redis) Advanced Containerization / Orchestration Kubernetes for deployment and scaling Advanced Containerization / Orchestration Docker container build Advanced Testing Writing comprehensive unit, integration, and end-to-end tests Advanced Core Experience 7+ years of professional experience in backend software development, with a significant focus on building and operating microservices in a production environment. Proven ability to work with and contribute to large-scale, distributed systems. Experience with cloud platforms (AWS, Azure, or GCP) for deployment, monitoring, and scaling. Desired Qualifications Process & Tools CI/CD: Experience setting up and maintaining automated deployment pipelines Observability: Proficiency with monitoring and logging tools Source Control: Expertise in Git and collaborative workflows Architecture & Design Familiarity with event-driven architectures and streaming data processing Experience with security best practices in API design (e.g., OAuth 2.0, JWT, input validation) Knowledge of perform