Backend Engineer, SaaS Billing & Subscriptions

Simular; Singapore; Hybrid; SGD 120,000 - 180,000; Full time

Job summary

Simular is building AI agents that streamline business workflows through robust backend services. This role focuses on monetization, accounts, subscriptions, billing, and entitlements, with an emphasis on dependable, auditable financial records and resilient event processing.

You will design and implement domain models for accounts, organizations, plans, and pricing, while integrating Stripe and other providers. This is a hands-on backend role in a fast-paced SaaS environment.

Qualifications

• BS/MS in Computer Science or equivalent experience.
• 5+ years of backend engineering experience in production systems.

Responsibilities

• Own domain models and APIs for accounts, subscriptions, pricing, and entitlements.
• Build billing systems with metering, invoicing, credits, prorations, upgrades, and downgrades.
• Integrate Stripe and other payment providers across checkout and recurring payments.
• Design robust payment and billing state machines that are idempotent and replay-safe.
• Create interfaces for reconciliation, audit trails, and billing exception handling.
• Collaborate with product and customer teams to translate requirements into maintainable systems.
• Ensure high accuracy of charges and entitlement provisioning to maintain customer trust.

Skills

Backend engineering

B2B SaaS

Stripe integration

Relational databases

API design

Retryable/replay-safe systems

Domain modeling

Education

BS/MS in Computer Science

Tools

Stripe

Job description

Simular is building AI agents that streamline business workflows through robust backend services. This role focuses on monetization, accounts, subscriptions, billing, and entitlements, with an emphasis on dependable, auditable financial records and resilient event processing.

You will design and implement domain models for accounts, organizations, plans, and pricing, while integrating Stripe and other providers. This is a hands-on backend role in a fast-paced SaaS environment.