Software Engineer
Hyojung Softtech
- Current
- May 2026 - Present
- Ho Chi Minh City, Vietnam
Business SaaS and multi-platform point-of-sale products for the Korean and Vietnamese markets. Platform-side developer on HOJA (hoja.vn), a multi-tenant business and social-marketing SaaS (Next.js, React, TypeScript, Apollo GraphQL, NestJS, Prisma, PostgreSQL, Redis, BullMQ, Docker; team of 2), owning work end to end from tenant-isolated data models, background processing and third-party social-platform integrations to product UI and day-to-day production operation; also builds Bread Factory, a multi-device POS product (Flutter, Dart, Ferry GraphQL, Drift/SQLite, WebSocket, DeviceBridge; team of 4), and works on UNION POS (RestaurantGLB), a point-of-sale system for restaurants in Korea and Vietnam.
HOJA
- Multi-tenant platformtenant-isolated data access with organizations, roles, capability-based permissions and per-tenant entitlements and quotas, enforced consistently across the Next.js client and the NestJS API.
- Work management & collaborationprojects, task lists and a drag-and-drop Kanban board with subtasks, assignees, rich-text descriptions, comments and attachments, plus presence tracking and optimistic-concurrency conflict detection.
- Social channel integrationsOAuth onboarding, token refresh and publishing for Facebook Pages, Instagram, Threads, TikTok and YouTube through an in-house TypeScript social SDK published to npm.
- Zalo OA integrationplatform- and tenant-scoped Official Account channels with app-secret-proof OAuth, HMAC-signed webhooks, inbox and delivery-state events, ZNS template tracking and follower sync.
- Marketing & influencer suitecampaigns, an influencer directory with TikTok research tooling and stateless HMAC-signed apply links; scheduled publishing and provider sync run as retry-safe BullMQ/Redis workers.
- Business modules & i18ncustomer, HR and company-settings screens covering Vietnam's pre- and post-2025 address formats, on end-to-end typed GraphQL contracts and a Korean/Vietnamese bilingual interface.
- Delivery & operationsDocker Compose releases behind a Cloudflare Tunnel with health-check-gated rollouts, incident triage and platform app-review submissions — TikTok app live with Login Kit and Content Posting API.
Bread Factory POS
- Order lifecycle & realtimeorder entry, modification and settlement across cashier, kitchen and payment surfaces, synchronised between terminals while preserving terminal-specific local state.
- Offline-firstDrift/SQLite persistence, crash recovery and reconciliation so terminals keep selling without network.
- Hardware & architectureprinters, scanners, cash drawers, payment terminals and scales through a device bridge, on Ferry GraphQL codegen with layered Presentation/Application/Domain/Infrastructure boundaries.
UNION POS
- Restaurant salestable and counter ordering, kitchen tickets, checkout with cash, card and QR payments, receipts and daily sales reports for restaurant chains in Korea and Vietnam.
- E-invoicingVAT e-invoices issued straight from the sale through Viettel S-Invoice, MISA meInvoice and WeTax, with company lookup by tax code and a QR on the receipt so guests can request their invoice.