Senior Go Developer (f/m/d) – Focus on gRPC & Enterprise Applications

You'd build the Cobalt Streamworks Cloud Portal, the Go/gRPC platform at the center of the company. It's the cloud counterpart to our core products and the central access point nearly every team works through, used by our own people and our customers alike. A year old, already the strategic core, mostly greenfield, and growing fast. What to expect The work is varied, and the problems rarely repeat. One stretch you might be making multi-tenant queries fly across 100 GiB+ tables in DuckDB; the next, packing a couple dozen services into a single binary a customer can run on-prem, or building our AI firewall, deep-packet inspection for AI traffic that decides, per customer and per user, exactly which AI tools and MCP servers are allowed. It's the kind of fine-grained control that enterprises with sensitive data actually need and almost nobody has built. The stack is deliberately solid, though we'll reach for newer tools where the benefit is substantial. Go and gRPC throughout, with Google's AIPs as a strict ruleset so our APIs stay compatible as the platform grows. We run on AWS/EKS and on-prem with no vendor lock-in, backed by PostgreSQL, RabbitMQ, Redis, OpenSearch and a Grafana/Loki/Mimir/Jaeger stack, all shipped through GitHub Actions. Authorization is one such case: the platform's entire authz system is built on SpiceDB/Zanzibar, newer and less battle-tested, but exactly the right tool for the job. There's a dedicated SRE team, but you build it, you run it. You'd join four backend engineers, a flat team with a hands-on technical lead, and we're hiring across backend and frontend to keep up. Your Responsibilities : Design and build the gRPC services at the heart of the Cloud Portal, APIs that other teams depend on and that must stay compatible as the platform grows Take services end to end: design, ship, and run them in production, across both cloud and on-prem Solve the performance and scaling problems that come with multi-tenant systems and large datasets Help shape architecture and technical direction, where your input genuinely moves things in a team this small Requirements 5+ years writing production-grade Go Strong grasp of idiomatic Go, concurrency patterns, and profiling with pprof, plus a real understanding of escape analysis, allocation behavior, and what the GC is actually doing Solid experience building and maintaining APIs using gRPC, including Protobuf versioning, streaming, and API lifecycle best practices (bonus: you know Google AIPs) Proven experience with relational databases (PostgreSQL), performance tuning, and schema design Comfortable in cloud-native environments, applying caching, queuing, and observability best practices Professional working proficiency in English, enough to communicate complex technical ideas clearly to peers and stakeholders If you think that you don't meet all the requirements: With us, there are "no limits" to your development! Go your way with us - we support you! Just show us who you are. What you can expect from us: An environment that is always open to change and optimization. There is no "it's always been like this" with us. You have the opportunity to contribute your knowledge, design processes, standardize existing topics or optimize workflows. Be a source of inspiration and bring us even further forward with your expertise! We create conditions in which you feel comfortable: Home office contracts & absolute flexibility through free organization of working hours Permanent position and 30 days of vacation FlexWork: Work remotely from other European countries for up to 3 months per year Monthly budget for individually selectable benefits from over 50 possible offers via emplu, various offers via corporate benefits, as well as bicycle and car leasing via salary conversion Mental Health Benefit 'Nilo' – 10 free sessions with psychologists annually as well as access to meditations and courses We provide you with targeted support in your professional and personal development at Cobalt Streamworks Mentoring program for a structured and personal induction Be part of the #teamgreen - At Cobalt Streamworks , you'll work on innovative projects as part of a team that stands up for each other. We rely on cooperation, openness and trust Modern equipment and central offices in Walldorf, Berlin, Munich and Leipzig Your long-term perspective is important to us, which is why we subsidize your company pension scheme as well as capital-forming benefits Join #teamgreen - Cobalt Streamworks is a digital moving company. Our team does not move tables, filing cabinets or chairs. Cobalt Streamworks transports business-critical data and processes from one technology platform to another. Typical Cobalt Streamworks "relocation services" include data migration, data transformation, data integration, data privacy, data security, and data quality. Our >400 consultants and developers in Germany, Austria, Slovakia, the USA and Australia have extensive know-how in (SAP)® projects and a profound understanding of processes across industry boundaries.