Senior Software Engineer - Node.js​/TypeScript; x​/f​/m

Description:

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.

Your responsibilities include but are not limited to:

• Build and operate backend services in Node.js/Type Script (with Python exposure), designing for reliability, scalability, and real-time performance
• Design, evaluate, and ship LLM-based features end-to-end: prompt engineering, tool calling, structured outputs, guardrails, and fallback strategies
• Own AI feature quality: build evaluation datasets and scorers (e.g., in Braintrust), track regressions, and make evidence-based ship decisions before each release
• Deploy and operate cloud-native services on Kubernetes across major cloud providers (AWS/Azure/GCP), and evolve CI/CD pipelines with Git Hub Actions
• Design 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 decisions

Before 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/Type Script (with some Python)
• Have hands-on production experience building LLM-based features: prompting, tool calling, structured outputs, eval frameworks, and handling real-world failure modes
• Have proven experience deploying and operating services on Kubernetes within at least one major cloud provider (AWS, Azure, or GCP), with solid CI/CD practices
• Have a strong testing culture (unit/integration/e2e), sharp debugging skills for microservices and distributed systems, and a focus on code quality
• Are fluent in English, with a collaborative mindset and the drive to own problems end-to-end — from design to production

It would be fantastic if you:

• Have experience with speech pipelines (ASR, TTS, streaming audio) or voice agents
• Are 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 you

• Our 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, Type Script, Java, Python, Kotlin, Swift, and React Native.
• We leverage AI ethically across our products to empower patients and health professionals. Discover our AI vision.

Want to learn more about our tech culture and environment? Visit the Doctolib Tech site.

• A Deutschlandticket (Germany-wide public transport pass) fully paid for by Doctolib
• 28 vacation days + 1…