Senior Fullstack Developer – Business Automation (m/f/d)

We are responsible for, among other things, the central CRM HubSpot, through which all processes of our value chain run. Internal software products are integrated into our CRM infrastructure just as much as specific apps, e.g., for appointment booking upon customer inquiry. The next scaling step requires an even stronger focus on technical enablement of our own organization as well as the expansion and improvement of our own technical area of responsibility.

You will take over a mature, productive automation landscape: Part of our business logic currently runs as custom code directly in HubSpot workflows, and part runs in our own backend services. Both belong to you – and you actively shape how this architecture develops.

• Development of TypeScript-based automations and services along our entire value chain in HubSpot CRM

• Development of HubSpot Apps and UI Extensions (React) for our internal teams – from CRM Cards to Workflow Actions

• Management of scopes, token rotation, app versioning, and deployments (CI/CD)

• Development and operation of custom code automations that run as part of HubSpot workflows – including maintenance of the workflows themselves (triggers, enrollment criteria, error patterns)

• Conscious placement of logic: You decide what belongs in a workflow, what belongs in custom code, and what belongs in a backend service – and migrate logic to where it is testable and maintainable

• Analysis and resolution of incidents in the existing automation landscape, including data corrections and backfills via script

• Use of HubSpot CRM APIs for objects, associations, and batch operations

• Use of webhooks & subscriptions for event-driven synchronization

• Building robust retry, error handling, and monitoring mechanisms – including conscious handling of rate limits and data volumes

• Definition of object relationships, ownership logic, and lifecycle states

• Ensuring data consistency across multiple systems

• Technical connection of internal and external systems (e.g., billing, metering, energy backends, own tech stack)

• Building clean interfaces between HubSpot and productive core systems

• Active participation in shaping the long-term CRM & integration architecture – including the gradual migration of complex business logic from workflows into testable backend services

Software Engineering

• At least 5 years of experience in web application development, with a clear focus on backend

• Very good knowledge of TypeScript; solid React knowledge for our CRM Cards and UI Extensions (NestJS is a plus)

• Experience with REST APIs, asynchronous systems, queues, and event processing

• Understanding of clean API contracts, versioning, and testing – you know when a pattern helps and when it's ceremony

• Several years of experience with API and event-driven integration of SaaS platforms (CRM, Billing, etc.) – practical experience with the HubSpot Developer Platform (Private/Public Apps, OAuth 2.0, Scopes, Webhooks, UI Extensions) is a strong plus

• Experience in designing scalable CRM and integration architectures; you can embed HubSpot meaningfully into a larger system landscape

• Awareness of sensible automations, performance, platform limits, and data volumes

• You work daily with AI assistants and are responsible for the results: You decide what you delegate and review what comes back

• Incompletely defined tickets do not deter you: You want to know who uses a feature and why, actively clarify open points, and sometimes say no to features that are not profitable

• Ownership mindset instead of ticket processing: You work independently, take responsibility for your topics, share your knowledge, and feel comfortable in startup structures

• Team-oriented and direct in communication; you can explain a technical trade-off to a non-technical person from Product, Operations, or Management

• Languages: German at least at B2 level, written and spoken

• Flexible Work Arrangements: Enjoy maximum flexibility with the option for hybrid work in Hamburg – we would like to meet 1-2 days a week in the office, you can work remotely the rest of the time

• On the Move: Subsidy for the Deutschlandticket or single tickets, plus bike leasing via salary conversion – get your desired bike cheaply, 100% for private use.

• Fit & Healthy: With our Urban Sports Club subsidy, you can train in thousands of studios and courses nationwide, from yoga to climbing.

• Provision: We subsidize your company pension – for your future after metergrid.

• Community: Regular cross-departmental events at our locations bring the entire team together.

• Freedom to Shape: We are a motivated startup team without hierarchical levels. Here you can implement your ideas and actively help shape the direction.

• Growth Opportunities: Your personal and professional development is important to us – we offer you diverse opportunities to develop in new directions.

• Meaningful Task: You are not just working for a job, but for a mission: the energy transition. In five years, you can proudly say that you were part of it!

• Fast Learning Curve and Self-Responsibility: From day 1, you are in the thick of it. We rely on you and your skills and support you in your development.

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