Full Stack Engineer

About the job Full Stack Engineer (Go) – Payments & Money Movement (Hybrid Jakarta) About Xellar

Xellar is building the infrastructure layer for digital money movement in Southeast Asia.

Our focus is on

Payment gateway infrastructure

Merchant settlement systems

Fund orchestration & routing

Wallet-based transaction systems

Cross-rail money movement (bank, e-wallet, blockchain)

We are building systems that process, settle, and reconcile real financial transactions at scale.

We’re looking for a Backend Engineer (Go) to build the core backend powering Xellar’s payment gateway and money movement arm. Role Overview

You will design and develop high-performance backend systems in Go (Golang) that power:

Merchant payment processing

Transaction orchestration

Settlement engines

Internal ledger systems

Reconciliation pipelines

Multi-rail fund routing infrastructure

This role is critical to Xellar’s core financial stack. What You’ll Be Building

1.

Payment Gateway

Infrastructure

Design and implement merchant payment processing systems

Build transaction lifecycle management (initiation → authorization → settlement → reconciliation)

Handle high-throughput transaction systems

Build idempotent and fault-tolerant processing flows

Design webhook systems for merchant updates 2.

Money

Movement & Fund Orchestration

Build routing engines across

Bank transfers

E-wallet networks

Internal wallet balances

Blockchain rails

Implement smart fund routing logic

Design real-time and batch settlement pipelines

Manage liquidity allocation logic 3. Ledger & Reconciliation Systems

Develop internal ledger architecture

Maintain accurate balance tracking

Implement double-entry accounting logic

Build reconciliation services between

Internal ledgers

Banking partners

Payment providers

Design audit trails and traceability systems 4. API & Integration Layer

Build REST / gRPC APIs for merchants and partners

Design secure authentication systems

Integrate with external payment providers and banks

Maintain clean API versioning and documentation 5. Performance & Reliability

Build systems optimized for

High availability

Low latency

Horizontal scalability

Implement queue-based architectures (Kafka, NATS, RabbitMQ, etc.)

Design retry logic and failure recovery mechanisms Technical Requirements

Must Have

Strong production experience in Go (Golang)

Deep understanding of

Concurrency (goroutines, channels, context)

System design principles

Distributed systems basics

Experience with

PostgreSQL or MySQL

Redis

Message queues

RESTful API design

Experience working with financial transactions or high-integrity systems Nice to Have

Experience building

Payment gateways

Settlement systems

Ledger/accounting systems

Familiarity with

QR-based payments

E-wallet integrations

Banking APIs

Stablecoin or blockchain integrations

Knowledge of compliance, AML monitoring logic, or transaction risk systems Who You Are

You understand that financial infrastructure must be precise.

You think in terms of edge cases and failure handling.

You design systems that are observable and auditable.

You care about clean architecture.

You can move fast without creating technical debt that will hurt later.

Why Join

Xellar

Build real payment infrastructure in Southeast Asia

Work directly on systems that move money at scale

High ownership and impact

Fast execution environment

Opportunity to shape Xellar’s money movement layer from the ground up