Backend Engineer - Crypto and Payments

As a Backend Engineer for Crypto and Payments at GoTymeX, you build the ledger, posting, reconciliation, and financial-control capabilities for a stablecoin and digital-assets wallet. You join a team delivering the financial core that lets customers hold, send, receive, and spend digital dollars through a familiar banking experience across South Africa, the Philippines, and expansion markets in Asia and Africa. This is an online transactional-core role focused on building systems that calculate balances, record movements of value, prevent duplicate or missing postings, and explain each financial state change.

What you'll 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
• Contribute to event schemas, financial data contracts, versioning, replay, and backfill approaches that preserve the audit trail without corrupting balances
• Work with finance and treasury to create accounting evidence, GL exports, reserve and liquidity views, and material for audits and regulators
• Apply strong practices for schema design, migrations, indexing, partitioning, data retention, backups, recovery testing, and database performance
• Take part in financial-core technical design and code reviews, and share what you learn about ledger modelling, database correctness, and safe production practices
• Own monitoring and production support for the components you build, and contribute to reconciliation service levels, incident response, root-cause analysis, and controlled remediation with the wider team

What you bring

• 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 record
• Strong relational database and SQL skills, ideally PostgreSQL or MySQL, with understanding of schema modelling, transaction isolation, locking, concurrency, query performance, indexing, migrations, and recovery
• 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 track record building and operating reliable production services
• Experience with event-driven systems, including event replay, schema evolution, auditability, and eventual consistency
• Clear technical communication, able to work with finance, product, compliance, and operational partners to turn requirements into precise models and implementation decisions

Nice to have

• Experience in stablecoins, digital assets, crypto custody, exchange operations, or on-chain settlement
• Experience reconciling custody or ledger records to blockchain transaction events, confirmations, fees, and failed transactions
• Experience with Fireblocks, TigerBeetle, Modern Treasury, Mambu, Temenos, or similar financial-ledger or custody infrastructure
• Experience in card issuing or processing, payment acquiring, cross-border payments, treasury, FX, or regulated banking
• Experience with AWS serverless and event-driven services such as Lambda, EventBridge, SQS, and Step Functions, or Kafka as an event platform
• Experience designing data retention, partitioning, archival, and disaster-recovery approaches for financial records
• Experience with accounting exports, general-ledger integration, audit evidence, regulatory evidence, and operational controls
• Experience mentoring other engineers or taking ownership of a defined financial-core component

What we offer

• Competitive salary that recognizes your talent and potential, including 13th salary (pro-rata)
• Performance-based bonus and equity participation in Tyme Group
• Insurance coverage in accordance with Vietnamese labor law, plus premium health care for you and your family
• 20 days of annual leave: 15 annual leave, 3 sick leave, 1 birthday leave, and 1 Christmas leave
• Meal and parking allowances covered by the company
• Hybrid working model with flexibility to work from home or the office
• 40-hour work week, Monday to Friday
• International working environment and agile culture
• Development opportunities through expanded lateral roles, stretch assignments, or people leadership

About GoTymeX

GoTymeX is the engineering, product, and design organisation of the GoTyme Group, which builds digital banking products for customers in South Africa, the Philippines, and expansion markets across Asia and Africa. GoTymeX builds and runs the software behind those products, including a stablecoin and digital-assets wallet that delivers a familiar banking experience with digital dollars.