About the Role
We're building the Authentication & Authorization platform for a new FSA-regulated digital bank in Japan. The platform powers OAuth 2.0/OIDC-based login, token lifecycle, and identity management across four banking channels — officer dashboards, customer-facing apps, BaaS APIs, and third-party service provider integrations.
The team is located in Vietnam HCM city with high ownership. You'll own entire auth flows end-to-end — not just write tickets.
What You'll Build
- Token lifecycle — DPoP-bound access tokens, token exchange (RFC 8693), silent refresh, session management
- Passkey/FIDO2 — WebAuthn registration & login flows, step-up authentication for sensitive operations
- mTLS integrations — certificate-based service-to-service auth with external financial platforms
- Shared security library — Spring Boot starter providing standardized auth filters across all backend services
- Integration testing — Karate-based test suites covering all auth flows at scale
- Monitoring — Auth event observability, anomaly detection, audit trail completeness
Must-Have
Backend
- Over 10 years in server-side engineering, including 5 to 7 years specializing in Kotlin or Java with Spring Boot development.
- Redis — session management, distributed locking, caching
- PostgreSQL — schema design, migrations
- REST API design and HTTP security headers
- English proficiency (reading, writing, and verbal) — the primary working language across the team and organization for daily communication, code reviews, and technical documentation.
Security & Auth
- Strong Spring Security expertise — filter chains, OAuth2 Resource Server
- Working knowledge of OAuth 2.0 / OIDC — authorization code, client credentials, token exchange, introspection
- Understanding at least one: DPoP (RFC 9449), mTLS (RFC 8705), PKCE, FIDO2/WebAuthn
- Familiarity with JWT structure — claims, JWKS, key rotation
- Strong knowledge of authentication, authorization, session management, and secure web application development.
- Strong understanding of the OWASP Top 10 — common web vulnerabilities, mitigation, and secure coding practices
Infrastructure
- AWS — ECS/Fargate, Secrets Manager, VPC basics
- Terraform or similar IaC
- API integration testing (Karate preferred)
Nice-to-Have
- Experience with Authlete
- FAPI 2.0 Security Profile or financial-grade API standards
- Microsoft Entra ID — SAML/OIDC federation, FIDO2 key enforcement
- Cloudflare/ Akamia — mTLS termination, WAF, client certificate forwarding
- WebAuthn/FIDO2 ceremonies — attestation, assertion, discoverable credentials
- Fintech/banking background — FSA regulations, maker-checker patterns, audit logging
- Japanese language ability (reading/basic communication) — a plus for requirement docs
Why This Role
- 🏦 Real regulated bank — not a fintech startup, not a toy project. FSA-supervised, launching in Japan.
- 🔐 Cutting-edge security standards — FAPI 2.0, DPoP, WebAuthn/FIDO2. Few teams globally work at this intersection.
- 🚀 High ownership — small team, big scope. You'll own entire authentication channels, not just implement tickets.
- 🌏 Global collaboration — work with engineers across Japan, Vietnam, and India on a greenfield digital banking platform.
