Sunollo is building a premium residential energy platform that combines high-quality hardware, reliable installation operations, and software to make clean energy simple for homes in Singapore.
We are looking for a Backend Engineer (Platform) to design, build, and own revenue-critical backend systems. The initial focus of this role is to build the foundation of our billing platform, followed by broader platform and internal systems.
This role is suitable for a senior backend engineer who enjoys high ownership, clear scope, and building production systems that are reliable and maintainable.
Key Responsibilities
- Design and implement backend systems that are revenue-critical and operationally important
- Build a billing and invoicing engine supporting subscriptions and milestone-based payments
- Design clean, auditable data models and event logs with replay safety
- Integrate with third-party systems such as Xero using OAuth2, APIs, and webhooks
- Implement secure and reliable background jobs and workflows (subscriptions, reminders, billing milestones)
- Ensure system reliability through logging, monitoring, alerting, and failure recovery mechanisms
- Build backend APIs to support internal admin tools and customer-facing applications
- Collaborate closely with product, finance, and operations teams to deliver correct system behaviour
- Write well-tested, maintainable code for critical system paths
Job Requirements
Must Have
- Strong backend engineering fundamentals with experience shipping production systems
- Experience with PostgreSQL and practical database design
- Experience building and operating API integrations (OAuth2, webhooks, retries, idempotency)
- Strong understanding of system reliability, monitoring, and failure handling
- Ability to work independently with high ownership and minimal supervision
Good to Have
- Experience with billing systems, subscriptions, invoicing, or payments
- Experience integrating accounting or CRM systems (e.g. Xero, HubSpot, Salesforce)
- Experience with Supabase or managed Postgres / serverless environmentsExperience building internal tools or admin dashboards
- Startup or fast-growth company experience
Qualifications
- Degree in Computer Science, Engineering, or related field (or equivalent practical experience)
- Senior level preferred (5+ years of backend engineering experience); strong mid-level candidates may be considered