More than 150,000 businesses — including Google, Uber, Paypal, Visa, Tinder, and many others — rely on Sinch's Customer Communications Cloud to power engaging customer experiences through mobile messaging, voice, and email. Whether you need to verify users or craft omnichannel campaigns, Sinch makes it easy. Our AI-infused Super Network, APIs, and applications ensure you can connect with your customers reliably and securely, at every step of their journey.

At Sinch we "Dream Big", "Win Together", "Keep it simple", and "Make it Happen". As a Senior Software Engineer on the Context Storage team, you will design, build, and own the core data platform that captures, persists, and serves conversational context to AI agents operating across SMS, WhatsApp, and voice at scale. You will work on complex problems with high autonomy as part of a small senior team with significant impact.

You will collaborate with Engineering Managers, Tech Leads, Product Managers, Domain Architects and cross-functional teams. Own the data model and storage architecture that represents conversational context in DynamoDB, designed for fast, consistent, and cost-efficient access by AI agents multi-table strategies, and read/write access patterns on DynamoDB Build event sourcing / CQRS-style systems that reconcile high-throughput event streams via Kafka with strongly consistent context reads Write production-grade Go services, including clean, maintainable code with tests and documentation; Own the full lifecycle of the systems you build: design, deployment, monitoring,



and on-call responsibilities Design APIs and data contracts that let AI agent platform teams retrieve relevant context efficiently, addressing challenges like data freshness, TTL/retention, partition key design, hot partitions, and query latency at scale Optimise DynamoDB capacity modes, indexing (GSIs/LSIs), and access patterns for cost, throughput, and latency as event volume and agent concurrency grow Collaborate across teams with product and technical stakeholders, providing technical guidance on trade-offs between consistency, availability, and performance 5–8+ years of professional software engineering experience. Strong backend and platform skills including distributed systems, microservices, event-driven architectures, event-sourcing systemsand cloud-native design on AWS Experience with Kafka or other event-streaming platforms Solid backend engineering experience in Golang (preferred)/Java/Node; Solid experience with data modelling and persistence at scale, ideally with DynamoDBor equivalent NoSQL experience Experience integrating with LLMs and vector databases in a backend or platform context Experience with AWS and operations including core AWS services (DynamoDB, EKS, etc.), Docker, Kubernetes, CI/CD, infrastructure as code, and monitoring Strong engineering fundamentals including clean code, testing strategies, debugging production systems, and building reliable, long-lasting systems Experience using AI coding tools such as Copilot, Claude Code, Cursor, or similar, with an understanding of their benefits, risks, and best practices Fluency in English It's a plus if you also have: At times, we may include a data-driven assessment to enhance our hiring success and identify candidates likely to excel.

📌 Senior Software Engineer C# - FLEXIBLE WORKING (Madrid)
🏢 Sinch
📍 Madrid