OUHALO PTE. LTD. Hiring! Full Time Backend Engineer in Central Region (Singapore), Earn up to SGD 5,000 - Ricebowl

About the role

A Singapore-based mobile virtual network operator offering travel eSIM plans through its app and website. You will write and run the backend services that turn a paid order into a working eSIM. You will also configure data packages on upstream platforms and help Operations verify what travellers can buy and use.

What you will do

• Design and maintain REST APIs and database schemas for orders, eSIM provisioning, activation, usage and top-ups. Write documented, testable code that Product, Frontend and Operations can build on.
• Integrate each provider from sandbox to production. Map provider package IDs to retail SKUs, process webhooks or poll for status, and make retries safe. If a provider times out after creating an eSIM, reconcile the order before sending another request.
• Create and test packages in provider portals. Configure coverage, networks, data allowances and validity. Document when validity starts, when daily data resets, how fair-use throttling works and whether top-ups extend the plan.
• Work with Product, Frontend, Payments and Operations to test an order from payment confirmation to first data use. Check that the package a customer receives matches the offer on the website and in the app.
• Deploy and monitor backend services, write automated integration tests and investigate slow or failed requests. Give Operations tools to trace orders, explain provider-specific issues and confirm recovery with a test order.

What you bring

• Hands-on backend development in at least one of Java, Go, Python, PHP or JavaScript (Node.js). Experience designing REST APIs and working with MySQL, PostgreSQL or a comparable relational database.
• Experience personally building, deploying and supporting a third-party API integration. You can explain how you handle authentication, asynchronous updates, duplicate requests and production failures.
• Travel eSIM, mobile roaming or MVNO industry experience is required. You have personally created and tested data packages on different upstream platforms and can explain their differences to Operations.
• Degree in Computer Science, Software Engineering or a related field. We typically look for 2+ years of backend experience. Recent graduates who gained the relevant hands-on experience through internships are welcome to apply.