Senior Backend Engineer - Core

Senior Backend Engineer (Core, Agents, Learn)

Sana

ABOUT SANA Sana is an AI lab building superintelligence for work. We believe organizations can accomplish their missions faster when teams can effortlessly access knowledge, automate repetitive work, and learn anything with the help of agentic AI. As part of Workday, we are committed to building AI that augments people - not replaces them. We bring this mission to life through two products. Sana Agents provide a seamless way to access all your company’s apps, knowledge, and data, enabling AI agents to do real work so teams can process and act on information at unprecedented scale. Sana Learn is an AI-powered learning hub that combines the simplicity of a modern learning platform with intelligent features like an AI tutor, automated content generation, and interactive apps, making knowledge not just accessible but actionable. We’re a talent-dense, product-obsessed team of engineers and designers from companies like Google, Spotify, Apple, and Databricks, united by deep technical excellence and rapid iteration. Our tools already help over a million people learn and work better across hundreds of leading enterprises - and we’re just getting started. ABOUT THE ROLES You will work on the core backend systems that power Sana’s Learn platform and search infrastructure. You will redesign and scale systems to handle enterprise workloads, remove deep bottlenecks, and evolve our architecture for the era of AI and agents. We are hiring for two senior roles: 1. Senior Backend Engineer, Learn (Core Systems) 2. Senior Backend Engineer, Search 1. SENIOR BACKEND ENGINEER, LEARN (CORE SYSTEMS) ABOUT THE ROLE You will focus on making the Learn platform, especially Manage, Insights, and APIs, scalable and maintainable for enterprise use. You will take systems that work at current scale and redesign them to handle much larger volumes of data, users, and entities. The work is primarily architectural and system level, with strong emphasis on Postgres and database design. IN THIS ROLE, YOU WILL * Redesign existing components to support enterprise scale workloads * Analyze and resolve bottlenecks in storage, query performance, APIs, and data models * Lead migrations away from legacy implementations to sustainable replacements * Improve reliability and efficiency of APIs and integrations for internal and external clients * Drive technical projects from definition to delivery with Product Managers and other teams * Maintain a long term view of system health and architecture * Share technical knowledge, review designs, and set best practices for backend and systems design WHAT SUCCESS LOOKS LIKE * Architecture and scalability are prioritized over short term fixes * Risks are identified early and addressed with solid technical solutions * You balance hands on coding with architectural leadership * Learn core systems support larger enterprise customers without performance or reliability issues * Strong Postgres skills (schema design, query optimization, indexing) improve performance and scalability 2. SENIOR BACKEND ENGINEER, SEARCH ABOUT THE ROLE You will build and scale Sana’s search infrastructure for enterprise scale knowledge discovery. You will architect retrieval systems, ranking algorithms, and search APIs that handle large increases in volume while maintaining sub second latency and high relevance. You will rethink the search stack for the era of agents, using engines like Vespa, vector databases, and embedding models. IN THIS ROLE, YOU WILL * Architect and scale search infrastructure to billions of documents in multi tenant environments * Design hybrid search that combines keyword search with semantic understanding and vector search * Build ranking and personalization systems that learn from user behavior * Collaborate with AI engineers to integrate large language models into the search pipeline and build retrieval augmented systems * Optimize search performance across query parsing, index design, and distributed architecture * Lead development of search observability and quality frameworks with clear metrics and monitoring * Work closely with product and design to shape the future of knowledge discovery at Sana WHAT SUCCESS LOOKS LIKE * Search systems scale elegantly to billions of documents and millions of queries with strict latency targets * Systems apply proven IR techniques and practical advances in semantic AI retrieval * Search quality issues are detected early through strong observability and automated regression checks * You balance implementation with system design and mentor others on search and IR fundamentals * Deep expertise in search infrastructure (index optimization, query planning, distributed retrieval, caching) prevents performance issues before users see them * The stack evolves from traditional search to AI powered discovery, including embeddings, reranking, and RAG, while staying reliable * Search infrastructure supports enterprise deployments with strict SLAs, multi tenancy isolation, and very high uptime OUR TECH STACK We build on a simple modern stack optimized for both humans and AI. * Backend: TypeScript, Kotlin, Node.js * Frontend: TypeScript, React, Tailwind * Databases: Postgres, Redis * Cloud infra: GCP/Kubernetes/Terraform WHAT WE OFFER * Help shape AI's future alongside brilliant minds from Google, Apple, Spotify, Notion, Slack, Databricks, and BCG. * Competitive salary complemented with a competitive RSU program. * Swift professional growth in an evolving environment, supported by a culture of continuous feedback and mentorship from senior leaders. * Work with talented teammates across 5+ countries, and global customers, from our beautiful office in Stockholm.

(Senior) Backend Engineer - Core Team (all genders)

envelio

ÜBER DAS ARBEITEN BEI ENVELIO Zu einfach ist langweilig! Gemeinsam haben wir die Mission, die Energiewende voranzutreiben. Wir lieben, was wir tun und dabei ist uns kein Thema zu groß. Wir übernehmen Verantwortung für unsere Arbeit und wachsen an jeder neuen Aufgabe. Kurz gesagt: Own it, love it, grow with it. Wir sind ein bodenständiges Team aus Kaffee- und Mate-Liebhaber:innen. Unser Geek-Humor resultiert in einer rituellen Nutzung von Emojis und der enzyklopädischen Herausarbeitung von unnützem Wissen. Mehr als 150 envelianer:innen mit über 20 verschiedenen Nationalitäten sind bereits an Bord. Komm dazu und wachse mit uns! DEINE ROLLE Als (Senior) Backend Engineer - Core Team (all genders) bist du Teil eines erfahrenes Entwicklungsteams mit Schwerpunkt auf Systeminfrastruktur und -architektur, Datenmodellierung und Graph-Funktionalität. Gemeinsam treibt ihr die Entwicklung des GridHub voran - unserer Kernkomponente, aus der alle Applikationen gespeist werden - und nehmt damit direkten Einfluss auf unsere Nutzer, unsere Organisation und die technischen Verfahrensweisen.  WIE DU ETWAS BEWIRKST * Du bist Teil des Core-Teams, in welchem du die Kernfunktionalitäten des digitalen Zwillings verantwortest, indem du robuste Interfaces und generalisierte Lösungen zu komplexen Anforderungen konzipierst. * Du entwickelst und erweiterst App-übergreifende Workflows, die die Datenintegrität für Planungs- und Live-Applikationen sicherstellt. Dabei bist du stets bemüht, die App-spezifischen Anforderungen in einer allgemeingültigen Lösung zu erfassen. * Du machst dich mit unseren individuellen und domänen-spezifischen Lösungen in der Modellierung und Berechnung von elektrischen Verteilnetzen vertraut und entwickelst diese eigenständig und innovativ weiter. * Du bist aktiv an der Gestaltung und Verbesserung unserer Systemarchitektur im Bereich Code, Datenmodel und Infrastruktur beteiligt. * Du tauschst dich mit anderen Entwickler:innen aus, um eine reibungslose Interaktion zwischen den unterschiedlichen Komponenten zu ermöglichen. DEIN PROFIL * Du hast +3 Jahre einschlägige Erfahrung in der Entwicklung von Webanwendungen mit dem Schwerpunkt auf Backend-Komponenten, Datenmodellierung und Infrastruktur * Du hast Erfahrung mit relationalen Datenbanken in der Architektur von Datenmodellen, bevorzugt von Digitalen Zwillingen, und das Design von Abfragen, bevorzugt in PostgreSQL. Erfahrungen mit Graph-Datenbanken sind ein plus * Du hast umfangreiche Erfahrung mit Python, idealerweise im Zusammenhang mit der Orchestrierung und Parallelisierung von Tasks im Rahmen von Multi-Processing, z.B. mit Celery * Du hast Erfahrung im Umgang mit Graph-Daten, zum Beispiel im Umgang mit Graph-Datenbanken oder Tooling wie NetworkX * Du bist ein Teamplayer und arbeitest leidenschaftlich gerne mit talentierten und inspirierenden Menschen zusammen * Du bevorzugst komplexe, technische Herausforderungen und hast einen hohen Anspruch an deine ausgearbeiteten und intelligenten Lösungen * Du bist mit den wesentlichen Teilen unseres Tech Stacks vertraut und freust dich darauf, mit den aktuellen Best Practices der Branche Schritt zu halten * Optional kennst du dich in einem oder mehreren der Themenbereiche Distributed Computing, Graphentheorie, Geoinformatik und Elektrotechnik aus * Du verfügst über verhandlungssichere Englischkenntnisse (Niveau C1) WIE WIR SOFTWARE ENTWICKELN * Agile Arbeitsweise mit Kanban in interdisziplinären Squads * Kontinuierliche Integration & Bereitstellung * Unittest-Mentalität und 4-Augen-Prinzip während Code-Reviews * Wissensaustausch zwischen den Entwicklern * "You Code it - You Own it" – Squad-Verantwortung für bestimmte Funktionsbereiche des Produkts UNSER TECH STACK * Python, inkl. zusätzlicher Pakete/Frameworks wie z.B. FastAPI, Pytest und Celery * PostgreSQL * RabbitMQ, Redis * Docker, Kubernetes DEINE BENEFITS * Flexibler Arbeitsort innerhalb Deutschlands: hybrid, von zu Hause aus oder in unserem schönen Office in Köln * Option zum mobilen Arbeiten aus dem Ausland (bis drei Monate pro Jahr von überall in der EU oder den USA)  * State of the art technology und modern Tech-Stack  * Sehr gute Hardware-Ausstattung (16 Zoll MacBooks, 2 Bildschirme an deinem Arbeitsplatz) * Unterstützung deiner Gesundheit mit der Urban Sports Club Kooperation  * Professionelle Unterstützung rund um mentales Wohlbefinden für dich und deine Familie durch unseren Partner nilo * Flexible Nutzung eines monatlichen Mobilitätsbudgets (z.B. Jobrad, ÖPNV)  * Zeit und Budget für individuelles Wachstum * Regelmäßige Tech & Growth Talks für internen Wissensaustausch * Optionale betriebliche Altersvorsorge  * Regelmäßige Company und Team Events

Senior Backend Engineer - Core Experience

Unknown Employer

Description Position at LeoVegas Group ABOUT THE ROLE Are you an experienced software engineer looking for a meaningful role in a dynamic environment? Join our Markets Platform Team at LeoVegas Group, where you will play a crucial role in enhancing our global customer onboarding process and developing responsible gaming features. Your work will ensure a seamless, secure, and enjoyable experience for our customers across all our brands. In this position, you will focus on refining the onboarding journey and promoting responsible gaming. Our mission is to create a safe gaming environment where players can set healthy limits on their gambling habits. We leverage data-driven insights and a robust CI/CD process, following the Kanban methodology to deliver high-quality solutions. You will work alongside expert back-end developers specialising in Java and Kotlin, as well as dedicated Quality Assurance Engineers. YOU WILL BE RESPONSIBLE FOR: ● Developing a multi-brand gaming platform called Rhino, built on 230+ microservices. ● Driving continuous improvement in the player onboarding process and responsible gaming solutions through innovative solutions. ● Writing extensive tests (units, e2e, integration) and updating documentation. ● Participating in architectural discussions and suggesting ideas for technical improvements. ● Collaborate with Product Managers and other stakeholders to deliver innovative solutions that enhance customer experience and promote safe gaming practices. ● Working closely with Backend Engineers, QA Engineers and TA Engineers. OUR SUCCESSFUL CANDIDATE WILL HAVE THE FOLLOWING: ESSENTIAL SKILLS ● Min. 5 years of experience in using Java + Spring Boot framework, or similar experience in Object Oriented Languages (C#, C++, Python, PHP) and willing to learn Java ● You have experience with SQL and relational databases ● You are familiar with microservice architectures NICE TO HAVES ● Experience with Kotlin, Git, Kafka, Jenkins. ● Familiarity with Google Cloud Platform and BigQuery. ● Strong understanding of API testing methodologies and hands-on experience with tools like Postman. ● Knowledge of Automated Testing. ● Experience with telemetry and monitoring. WHO WE ARE At the core of LeoVegas Group is Team Leo. Our culture is our foundation and is what enables us to innovate, build, and lead as we trailblaze our way through the igaming industry. We’re a team of over 1400 innovators, initiators, and groundbreakers working in a fast-paced and agile environment across 11 offices worldwide. BENEFITS ● Hybrid work policy ● 4 weeks of Workation  (T&C apply) ● Benefits package - 800 PLN net (B2B)/gross (UOP) monthly with access to the cafeteria platform (private medical care, insurances, sports card) ● Training budget ● ICAS assistance program that can provide help and guidance during challenging moments. ● Our office provides complimentary snacks and drinks; on Mondays, we serve complimentary breakfast. ● Team and office social events throughout the year ● Free parking for bicycles and motorcycles ● Free gym in the building ● Equipment: MacBook Pro + smartphone (iPhone 16/17 or Samsung Galaxy S25) JOIN US! In our pride, we empower our teammates to find their roar and run with their wildest ideas. We don’t wait for things to happen; we pounce and make it happen! Would you be a good fit for the Leo Pride - give us a roar! **As our company working language is English, we’d like to see your CV in English, please**