Backend Engineer - Crypto and Payments
- Compensation
- Not disclosed
- Location
- Ho Chi Minh City, Ho Chi Minh, Vietnam
- Work setup
- Remote
- Seniority
- Not specified
- Employment
- Contract
- Experience
- 5+ years
- Category
- Backend
- Posted
Skills
Must have
- 5+ years of backend engineering experience, including meaningful hands-on work on payments, ledger, accounting, settlement, core banking, or another high-integrity transactional system.
- Experience building, operating, or making substantial contributions to a double-entry ledger, payment posting engine, settlement platform, core-banking subsystem, or equivalent financial system of rec
- Strong relational database and SQL skills, ideally PostgreSQL or MySQL. You understand schema modelling, transaction isolation, locking, concurrency, query performance, indexing, migrations, and recov
- Working understanding of journals, debits and credits, chart of accounts, posting rules, available versus settled balance, holds, reversals, adjustments, fees, FX, and reconciliation.
- Practical experience with idempotency, outbox and inbox patterns, event ordering, duplicate delivery, exactly-once-effect design, and failure recovery.
- Experience building reconciliations that compare internal and external records, identify breaks, retain evidence, and support controlled repair.
- Strong Java or Python experience and a record of building and operating reliable production services.
- Experience with event-driven systems, including event replay, schema evolution, auditability, and eventual consistency.
- Clear technical communication. You can work with finance, product, compliance, and operational partners to turn requirements into precise models and implementation decisions.
Full description
About GoTyme
The GoTyme Group builds digital banking products for customers in South Africa, the Philippines, and expansion markets across Asia and Africa.
GoTymeX is the Group's engineering, product, and design organisation. We build and run the software behind those products.
About the Product
We are building a stablecoin and digital-assets wallet that lets customers hold, send, receive, save, and spend digital dollars through a familiar banking experience.
The financial core will be delivered in stages. In the first phase, a managed CASP ledger remains the authoritative operational financial record. GoTyme will build immutable event and audit records, a financial-control projection, and reconciliation capabilities around it. In the next phase, GoTyme's event-sourced, append-only double-entry ledger will become the product and accounting source of truth.
The system must stay correct across vendor events, internal state, on-chain settlement, fiat payment rails, card settlement, fees, FX, holds, and operational exceptions.
The role
We are looking for a hands-on Core Backend Engineer with strong financial-systems and database experience to build Project White's ledger, posting, reconciliation, and financial-control capabilities.
You will build systems that calculate balances, record movements of value, prevent duplicate or missing postings, and explain each financial state change. You will work closely with finance, treasury, risk, compliance, operations, vendor-integration engineers, and senior engineers responsible for the wider financial-core design.
This is an online transactional-core role. It is not a reporting or data-warehouse position.
What you will do
- Build and improve an event-sourced, append-only double-entry ledger and its account, journal, posting, balance, hold, fee, FX, and adjustment models.
- Implement posting rules and invariants that keep journals balanced, prevent unauthorised value creation or loss, and provide a clear audit trail.
- Build transaction-processing flows for authorisation, holds, capture, settlement, reversals, refunds, chargebacks, expiry, corrections, and controlled manual adjustments.
- Apply idempotency, deduplication, sequencing, and concurrency controls to payment, card, custody, and blockchain events that may arrive late or more than once.
- Build reconciliation controls across the managed CASP ledger, Fireblocks, on-chain data, fiat ramps, card processing, treasury and accounting systems, and GoTyme's financial-control projection.
- Build operational workflows for missing events, duplicate notifications, amount or currency mismatches, unbalanced postings, and suspense or repair processes.