Senior Backend Engineer (B2B Contract) - Join Our Innovative Team

Role overview Jobgether seeks a Senior Backend Engineer to advance our B2B product development efforts in Spain. The focus is on building and maintaining backend systems that support solutions for business clients. What you will do Design, build, and maintain scalable backend systems tailored for B2B applications Collaborate with cross-functional teams to de…

About the Project:Yei Finance is a pioneering decentralized, non-custodial money market protocol built on the Sei network, dedicated to delivering innovative and versatile financial solutions. Users can benefit from competitive yields, borrow via over-collateralized or flash loans, and manage risks using advanced tools—all while harnessing Sei’s remarkable speed and low costs.Our flagship product, Clovis, achieved over $400M in Total Value Locked (TVL) at its peak, generated $5.5M in protocol revenue over the past year, and has established itself as the largest protocol on Sei. Furthermore, we launched the first lending-boosted decentralized exchange (DEX) on Sei, where YeiSwap compounds YeiLend yields to drive over $230M in monthly trading volume and $147M in bridge flow. Clovis is set to expand this successful model by becoming multichain, positioning itself as the cross-chain prime brokerage layer for decentralized finance (DeFi).Who We Are:A dedicated team of builders from esteemed Web3 organizations, including AAVE, Wormhole, Venus Labs, OKX, among others.Supported by leading investors such as Outlier Ventures, Manifold, DWF Ventures, and the Sei Foundation.Collaborating with industry giants like Circle, OKX Wallet, Binance Wallet, Frax, Stargate, and more.The Opportunity:We are on the lookout for a highly skilled Senior Engineer to become part of our core development team and take charge of the design and implementation of our next-generation cross-chain lending protocol. This role will emphasize smart contract security and architecture, as well as the development of essential off-chain services that guarantee the protocol’s efficiency and strength.What You’ll Do:Design, develop, and refine DeFi protocols on EVM-compatible chains, prioritizing contract architecture, security, gas optimization, and upgradability.Create crucial backend and off-chain services using Go or Python, including monitoring systems, liquidation bots, and liquidity rebalancers.Address cross-chain integration challenges, ensuring atomicity, data consistency, and reliable asset bridging in an asynchronous environment.Rapidly iterate in an Agile environment and produce comprehensive documentation and system architecture diagrams.Who You Are:Startup-oriented: Thrives in a dynamic, fast-paced environment.

jobgether seeks a Backend Developer to join its Research Group on a B2B contract. This position centers on developing and enhancing backend systems that support research-focused projects. What you will do Build and refine backend solutions for research initiatives Collaborate with a team that values creative problem solving and strong technical skills Location This is a remote role based in Spain.

Are you passionate about backend development? Join Delivery Hero as a Backend Engineer and be part of a dynamic team that drives innovation in the food delivery industry. In this role, you will design and implement scalable backend solutions, working with cutting-edge technologies to enhance our platform's performance. Collaborate with cross-functional teams to deliver high-quality software that meets the needs of our customers.

Join our dynamic team at bunch as a Senior Backend Engineer, where you will lead the design and development of innovative backend systems. You will collaborate closely with cross-functional teams to deliver high-quality software solutions that enhance user experiences. Your expertise will drive the architecture of scalable applications, ensuring they are robust and efficient.

Lead with impact, build with purposeJoin Betsson as a hands-on Senior Engineer and take the helm as the Team Lead for our dynamic Gaming Area. At Betsson Group, we are dedicated to revolutionizing Game Play and Game Discovery across all our brands and markets. Our mission is to deliver the finest gaming products and an exhilarating user experience for players on our platforms, encompassing game lobbies, gaming initiatives, provider integrations, and more.Key ResponsibilitiesYou will play a pivotal role in our Gaming platform, which is at the heart of our operations and essential to our company strategy. As we prepare to embark on our journey toward containerization, your expertise will enhance the scalability of our systems while ensuring top-notch quality. You will collaborate with a passionate team to build an industry-leading, scalable, multi-brand platform supporting over 25 online brands, utilized by hundreds of thousands of users worldwide.In summary, you will elevate our Gaming platform to new heights for a global audience!Your Role IncludesLeading a team of 7-8 engineers: motivating your team, participating in recruitment and onboarding, conducting performance reviews, and fostering personal development through 1-to-1 sessions.Engaging closely with Product Owners, Architects, and stakeholders to translate business requirements into actionable plans.Driving product development that aligns with business needs while implementing components in a modern software development environment (cloud platforms, microservices, etc.).Proactively contributing to solution development and process improvements.Participating in decision-making regarding application architecture design, solution development, and code reviews.Recommending technologies and approaches, discussing options with the team, and reaching consensus on technology choices.Collaborating in a cross-functional team where every member focuses on delivering exceptional results.

Are you a skilled Senior QA Automation Engineer looking to make a significant impact in a fast-paced and innovative environment? At Shiji Group, we are dedicated to enhancing the hospitality and retail industries with cutting-edge technology. Join us in Barcelona to lead the charge in ensuring the highest quality of our software solutions!

Join our dynamic Compliance Team as a Backend Engineer, where your primary focus will be on designing and building robust services that prioritize maintainability, performance, and security.If you thrive in an environment with high availability demands, scalability challenges, automated workflows, infrastructure orchestration, and have a passion for working with APIs and protocols like GraphQL and gRPC, we want to hear from you!Key Responsibilities: Developing an exceptional, user-friendly payment platform. Implementing new features and enhancements to elevate our platform's capabilities. Collaborating closely with Frontend and Mobile Engineering teams to ensure seamless UI integration. Working in partnership with product managers, designers, engineers, and other stakeholders throughout the software development lifecycle, from planning and design to implementation and support. Staying current with the evolving tech stack ecosystem. Writing high-quality, efficient code that emphasizes performance and scalability.

As a Senior Backend/Platform Engineer at causaprima, you will be responsible for the foundational platform utilized by our agents. Your expertise will enhance our event-driven architecture, streamline data pipelines, integrate with customer accounting systems, and ensure that our infrastructure is reliable, auditable, and efficient.Key ResponsibilitiesEvent Store Management — Design and maintain an append-only PostgreSQL database featuring tamper-evident hash chaining, real-time event distribution, agent replay, recovery capabilities, and schema versioning.Cryptographic Signature Infrastructure — Establish key management and signature verification systems for all agent events while implementing approval chains for external actions.Workflow Constraint Engine — Develop a gateway to verify authorization for any external actions including emails, payments, or API calls.PII Vault & GDPR Compliance — Create isolated, encrypted storage solutions for personal data, ensuring compliance with the right to erasure and data residency requirements.Multi-Tenancy Management — Implement row-level security and tenant isolation across all data stores, including tenant-scoped LLM API keys.Authorization Framework (Cerbos) — Utilize attribute-based access control for both agents and humans, ensuring deterministic policy evaluation where LLMs do not make authorization decisions.MCP Security Layer — Develop authentication, capability-based scoping per partner, and rate limiting for the Model Context Protocol endpoint.Database Architecture — Focus on PostgreSQL schema design, indexing strategies, performance tuning, and read replica topology.

About the Role resilientco is looking for a Senior PHP Backend Engineer based in Spain. This role focuses on building and maintaining backend systems that support core applications. The work centers on PHP and requires experience designing reliable solutions for modern software products.

We are seeking a talented and enthusiastic Hydraulic Engineer to join our dynamic team in Madrid. As a key member of our engineering department, you will play a vital role in designing and implementing innovative hydraulic solutions that meet our clients' needs. This position offers an exciting opportunity to work on diverse projects that impact the environment positively.

Join Aircall as a Senior Backend/Platform Engineer, where you will play a crucial role in enhancing our platform's infrastructure and backend systems. You will collaborate with cross-functional teams to design and implement scalable solutions that ensure seamless communication for our users. If you are passionate about crafting high-performance systems and thrive in a dynamic environment, we would love to hear from you!

As a Senior DevOps Engineer in the EMS Team at DTT, your expertise will be vital in enhancing our automation processes to meet the evolving demands of quality in validation, rollout, and operations. You will play a key role in interfacing with suppliers, managing test environments, and ensuring smooth operational activities.Key Responsibilities:Collaborate with the team to design and implement CI/CD pipelines for testing and operational tasks.Automate existing processes that have not yet been automated by the manufacturer.Develop sustainable, maintainable, and modular solutions for our systems.Implement and execute automated testing frameworks.Analyze test outcomes and provide detailed reporting.Assist in the administration of various environments.Create comprehensive development documentation.Objectives:Minimize repetitive tasks to enhance efficiency.Elevate the quality of validation, rollout, and operations.Boost software quality through improved test coverage.Aim to eliminate manual errors in processes.

Abacum is looking for a Senior Backend Engineer focused on integrations. This position is fully remote within Spain. Role overview This role centers on designing and building backend solutions that connect Abacum's product with a range of external systems. The work involves improving integration features while maintaining strong performance and scalability. What you will do Create and maintain backend services that enable seamless integration with third-party platforms. Enhance existing product capabilities by developing new integration features. Ensure backend systems operate efficiently and scale to meet business needs. Requirements Experience building backend solutions, with a focus on integrations. Strong understanding of system performance and scalability. Ability to work independently in a remote setting within Spain.

Join us at Fever, the premier tech platform dedicated to enhancing cultural and live entertainment experiences globally.Our mission is to democratize access to culture and entertainment. Utilizing our advanced technology and data-driven strategies, we are changing how audiences engage with live events. Every month, over 300 million individuals across more than 40 countries discover unforgettable experiences on our platform, while we empower event creators to innovate and grow their reach.We proudly collaborate with industry giants such as Netflix, F.C. Barcelona, and Primavera Sound, delivering internationally acclaimed experiences and backed by leading global investors. Impressive, isn’t it?To further our mission, we seek exceptional talent with a proactive mindset, eager to contribute to the future of entertainment. Are you ready to be part of this journey?The engineering team is the backbone of our user-friendly iOS and Android applications and website, responsible for developing, enhancing, and maintaining all Fever services, ensuring that users have outstanding experiences.About the RolePosition: Senior Software Engineer (Backend Platform)Location: SpainWe are looking for a highly skilled software developer with a proven track record of delivering exceptional results. A person who values code quality and emphasizes doing things correctly, not just completing tasks.Collaborate within an agile, cross-functional team alongside other talented software engineers and product designers.Develop production-quality code and implement solutions capable of handling significant traffic.Mentor team members through code reviews, architecture design sessions, and pair programming.Receive mentorship from colleagues in areas where you seek to grow.During your onboarding period, you will:Engage in a structured program designed to facilitate a smooth transition into your role.

fiskaly develops technology that secures digital receipts and ensures legally compliant transactions for millions of users each day. By applying digital signatures, the company helps prevent tax fraud and supports merchants with a streamlined, paperless solution. The team is dedicated to simplifying receipts for everyone. Role overview This Senior Backend Engineer (Golang) position is a full-time, permanent role open to candidates based in or near Vienna, or within a two-hour time zone difference. The company is not considering freelancers for this role. What you will do Serve as a System Architect within a focused squad, developing API-first SaaS products. Lead backend development using Golang and other object-oriented languages, contributing throughout the software lifecycle. Apply modern tools, including AI coding assistants and automation, to minimize repetitive tasks and tackle complex problems. Design, build, and maintain distributed systems for fiskaly's fiscalization platform. Shape the architecture and scalability of the unified digital receipts interface. Requirements Minimum 5 years of backend development experience, with a strong background in Golang and object-oriented programming. Fluency in both German and English. Located in or near Vienna, or within a two-hour time zone difference. Available for full-time employment (no freelance contracts). Salary and contract Gross annual salary: €45,000 – €70,000 Full-time, permanent position

Location: Madrid Office About Aircall Aircall builds an AI-driven customer communications platform used by over 22,000 businesses worldwide. Our product brings together voice, SMS, WhatsApp, and AI features in a single workspace, helping teams boost revenue, resolve issues faster, and scale their operations efficiently. Headquartered in Paris, Aircall has a strong global footprint with offices in Seattle, Madrid, London, Berlin, San Francisco, New York City, Sydney, and Mexico City. Our company is growing quickly, supported by leading investors and advances in AI across our product lines. Our Culture We focus on customer satisfaction, data-driven decisions, and meaningful results. Team members are encouraged to take ownership, keep learning, and act quickly but thoughtfully. Collaboration, trust, and impact shape our daily work. About the New Product Unit Aircall is launching a New Product Unit dedicated to advancing autonomous sales. The team is building an AI Orchestration Layer that records and understands customer interactions across calls, video, email, and WhatsApp. This system will automate sales workflows such as CRM updates, follow-ups, task creation, and coaching insights. Our long-term vision is a self-optimizing Sales OS powered by specialized AI agents working together to improve revenue processes. Role Overview: Senior Backend Software Engineer (Python) This position calls for an experienced backend engineer with strong Python skills, ready to work beyond traditional backend boundaries. The role suits someone who values both clean architecture and practical progress, and who can balance high-quality work with the need for speed in a startup setting. What You Will Do Tackle complex technical challenges, including distributed systems, AI orchestration, architecture, performance, and scalability Contribute to the design and implementation of backend systems for the AI Orchestration Layer Work closely with product and engineering teams to deliver new features Iterate quickly, shipping solutions and learning from feedback Who Will Thrive Engineers who enjoy solving difficult problems and making architectural decisions Those who can dive deep into technical details while keeping an eye on rapid delivery People who take pride in their work and appreciate the pace of a growing company

As a Senior Backend Software Engineer at Blacklane, you will join one of our autonomous agile teams. Your contributions will enhance the services that drive our innovative platform, improve our back-office systems, and address integration challenges that enable our business partners to seamlessly connect with Blacklane.Our tech stack comprises Ruby, Go, TypeScript, and Java services, designed through Domain-Driven Design (DDD). These services are deployed within our Kubernetes cluster and communicate via domain events using SQS and Kafka. We utilize a variety of data storage technologies, including PostgreSQL, MySQL, Elasticsearch, Redis, and DynamoDB. For infrastructure and cloud resources, we primarily leverage AWS, managing provisioning through Terraform.

ANYbotics is an innovative and rapidly expanding technology company committed to revolutionizing the field of mobile robotics across diverse sectors. We invite you to join our dynamic and talented team of over 200 professionals, working on pioneering robotic technologies.The OpportunityWe are searching for a Senior Backend Engineer to become a vital member of our agile software engineering team. In this role, you will be responsible for architecting and developing the backend for the next generation of robotic applications for our flagship product, ANYmal. Collaborating closely with your teammates and leading robotics engineers, you will design and implement sophisticated software solutions that empower ANYmal to undertake increasingly complex tasks.The APIs developed by your team will lay the groundwork for strategic partnerships with software and cloud technology providers, facilitating seamless integration into our clients' facility management systems and enabling the creation of comprehensive robotic inspection solutions.At ANYbotics, we continually innovate to enhance the performance and capabilities of our robots, helping clients derive valuable insights from their facilities and processes with efficiency and ease. Leverage your technical expertise in web technologies to contribute to making our robots smarter, more reliable, and user-friendly.The Market & Our TechnologyANYbotics is at the forefront of transforming the industrial landscape by integrating robotics into a wide array of groundbreaking applications that were previously unattainable (refer to our case studies in sectors such as Chemicals, Oil & Gas, Railways, Wind Energy, Mining, and Construction). Our clientele consists of major asset operators and service providers in the industrial sector, pioneering the use of robotic technology for inspection and maintenance tasks. Our solutions facilitate autonomous routine inspections and monitoring of extensive industrial facilities, enhancing safety and productivity. We engineer a variety of customized hardware systems, including the complete robotic platform, actuators, sensors, inspection payloads, charging systems, and software, achieving exceptional mobility, autonomy, and inspection capabilities, often powered by AI. Our technology has been validated through long-term pilot projects, and we are now scaling our solutions for commercialization, deploying them directly in operations at client facilities across the globe.About UsANYbotics is a pioneering robotics firm specializing in advanced autonomous systems. Following a successful Series B funding round, we are poised for significant growth...

Managing corporate spending can often be a challenging endeavor, with convoluted processes that hinder efficiency for finance teams and employees. At Pleo, we are revolutionizing this process. We provide financial solutions designed to simplify money management, making it seamless and remarkably efficient for everyone involved. Our mission is to empower businesses to 'go beyond' traditional spending methods.The name 'Pleo' translates to 'more than you’d expect', and this philosophy has underpinned our success over the last decade.We find ourselves at a crucial juncture in our growth; every decision we make impacts over 40,000 customers and is vital to our mutual success. We seek individuals who are committed to understanding customer needs, transforming complex challenges into straightforward solutions, and questioning the status quo—all while aiming high. With ambitious goals propelling us forward, we embrace the journey of discovery and innovation. Our team consists of over 850 talented individuals representing more than 100 nationalities, all dedicated to shaping the future of business spending.About the RoleWe are in search of a Senior Backend Engineer to join our dynamic team at Pleo. In this role, you will play a key part in developing and scaling our backend systems while engaging in exciting projects as we enhance our product and service offerings. If you are passionate about tackling complex technical challenges and thrive in a culture that prioritizes transparency, collaboration, and innovation, this position is made for you.Your ResponsibilitiesAs a Senior Backend Engineer, you will:Lead the design, development, and maintenance of scalable microservices primarily using Kotlin.Collaborate with cross-functional teams to create innovative solutions across various domains including Platform and Services.Analyze system performance and implement optimizations to ensure high reliability and scalability.Participate in code reviews, conduct post-mortems, and mentor fellow engineers.Proactively address technical debt and guide the team through technical challenges and migrations.QualificationsYou will excel in this role if you possess:Strong expertise in server-side programming, particularly in Kotlin, and experience with distributed systems, microservices, and various cloud environments such as AWS and Kubernetes.Proficiency in relational databases such as PostgreSQL, testing frameworks (e.g., JUnit, Testcontainers), and observability tools like Grafana.