Senior Software Engineer - Node.js/TypeScript (x/f/m)

Set a new pulse for healthcare!We are looking for a Senior Software Engineer to join the DIAL team in the Phone Assistant domain. Your mission will be to design, build, and scale the AI-powered features that transform how practitioners and patients connect over the phone — making care more accessible for patients and reducing administrative burden for health professionals. You will work in a feature team developing the Phone Assistant, Doctolib's solution that combines LLM reasoning, speech recognition, and real-time backend systems, launching first in Germany and expanding to France and Italy. Working in the tech team at Doctolib means building innovative products and features to improve the daily lives of care teams and patients. What you'll doYour responsibilities include but are not limited to: Build and operate backend services in Node.js/TypeScript (with Python exposure), designing for reliability, scalability, and real-time performanceDesign, evaluate, and ship LLM-based features end-to-end: prompt engineering, tool calling, structured outputs, guardrails, and fallback strategiesOwn AI feature quality: build evaluation datasets and scorers (e.g., in Braintrust), track regressions, and make evidence-based ship decisions before each releaseDeploy and operate cloud-native services on Kubernetes across major cloud providers (AWS/Azure/GCP), and evolve CI/CD pipelines with GitHub ActionsDesign data models and drive database migrations and performance tuning for real-time workloads (PostgreSQL: connection pooling, indexing, query optimisation)Maintain a high testing bar (unit, integration, e2e), debug distributed systems in production with strong observability, and contribute to pragmatic, secure architecture decisionsWho you areBefore you read on: if you don't have the exact profile described below, but you feel this job description matches your skill set, we still encourage you to apply. You'll be a great fit if you: Have 5+ years of backend engineering experience building scalable, resilient systems in Node.js/TypeScript (with some Python)Have hands-on production experience building LLM-based features: prompting, tool calling, structured outputs, eval frameworks, and handling real-world failure modesHave proven experience deploying and operating services on Kubernetes within at least one major cloud provider (AWS, Azure, or GCP), with solid CI/CD practicesHave a strong testing culture (unit/integration/e2e), sharp debugging skills for microservices and distributed systems, and a focus on code qualityAre fluent in English, with a collaborative mindset and the drive to own problems end-to-end — from design to productionIt would be fantastic if you: Have experience with speech pipelines (ASR, TTS, streaming audio) or voice agentsAre familiar with event-driven architectures and message brokers (Kafka, RabbitMQ, NATS, or Redis Streams), and have hands-on PostgreSQL experience (EXPLAIN/ANALYZE, indexing strategies, connection pooling)Have an interest in telephony and real-time communication (SIP, RTP, WebRTC) — no prior experience needed, we will teach youLife at Doctolib TechOur solutions are built on a single fully cloud-native platform that supports web and mobile app interfaces, multiple languages, and is adapted to country and healthcare specialty requirements.Our stack is composed of Rails, TypeScript, Java, Python, Kotlin, Swift, and React Native.We leverage AI ethically across our products to empower patients and health professionals. Discover our AI vision here.Want to learn more about our tech culture and environment? Visit the Doctolib Tech site. What we offerA Deutschlandticket (Germany-wide public transport pass) fully paid for by Doctolib28 vacation days + 1 additional day for each full calendar year of employment (up to a maximum of 30 days)Work from abroad for up to 10 days per year thanks to our flexibility days policyCompany health insurance with great supplementary benefits through our partner AllianzCompany pension scheme (bAV) through Allianz with an employer subsidy of 40% (15% within the probationary period)The Doctolib Parent Care program, which includes one month additional parental leave and much moreEnrollment in Doctolib's long-term employee value sharing plan called DoctoGrowthFree mental health and coaching services through our partner Moka.careSubsidized sports membership through our partner Urban Sports ClubA flexible workplace policy offering both hybrid and office-based modeAlongside healthy snacks and our regular breakfast buffet, we provide a subsidized meal benefitFor caregivers and workers with disabilities, a package including an adaptation of the remote policy, extra days off for medical reasons, and psychological supportRelocation support in case of international mobilityAccess to the best AI tools for coding, development and dedicated trainingOur interview processRecruiter InterviewLive Coding InterviewSystem Design InterviewBehavioral InterviewAt least one reference checkWe want your experience to be clear, respectful, and transparent. Learn more about our hiring process on our candidate experience page. Job detailsPermanent positionTech stack: Node.js/TypeScript, Python, Kubernetes, AWS/Azure/GCP, PostgreSQLFull-timeBerlinHybrid work setup (up to 2 remote days per week)Start date: as soon as possibleWe welcome everyoneAt Doctolib, we are committed to improving access to healthcare for everyone. This translates into our recruitment process. We evaluate candidates based solely on qualifications and motivation, without any form of discrimination. The more diverse ideas are heard, the more our product will truly improve healthcare for all. You are welcome to apply to Doctolib, regardless of your gender, religion, age, sexual orientation, ethnicity, or disability. To ensure equal opportunities, we invite you to exclude personal information (e.g., pictures, age) from your applications. If you require any accommodation, please let us know for support during the hiring process. Join us in building the healthcare we all dream of! Your data privacyAll information provided is processed by Doctolib for application management. For data processing details, click here: Germany | France | Italy | Netherlands. Please contact hr.dataprivacy(at)doctolib.com for inquiries or to exercise your rights.