Lead Backend Engineer, Payments Infrastructure & Automation

Codex; Singapore; Hybrid; SGD 120,000 - 160,000; Full time

Job summary

Codex is building the infrastructure for stablecoin-based cross-border payments. As a Software Engineer, you will own financial partner integrations end-to-end and contribute to an automation layer for trading and treasury operations.

You will collaborate with the Engineering & Product Development team, Compliance, Operations, and Financial Partnerships to design robust, secure systems capable of handling real money across fiat and crypto rails.

Qualifications

• 6 to 10 years of backend engineering experience in cross-border payments, stablecoins, or crypto infrastructure.
• Must have production experience with durable workflow orchestration (Temporal strongly preferred).
• Must-have: Strong TypeScript/Node and PostgreSQL in a money context.
• Hands-on third-party API integration with incomplete docs, webhook reliability, and schema instability.

Responsibilities

• Own financial partner integrations end-to-end from API contracts to reconciliation.
• Build robust integrations resilient to incomplete documentation and schema changes.
• Build messaging/notification systems with signature verification and replay protection.
• Maintain the reconciliation layer across payment rails and related operations.
• Identify manual workflows and replace with product-driven automation.
• Design automation for trading and treasury operations.
• Set and maintain engineering standards for payment integrations.

Skills

Backend engineering

Payments infrastructure

TypeScript/Node.js

PostgreSQL

API integrations

Tools

Temporal

Postgres

REST APIs

Job description

Codex is building the infrastructure for stablecoin-based cross-border payments. As a Software Engineer, you will own financial partner integrations end-to-end and contribute to an automation layer for trading and treasury operations.

You will collaborate with the Engineering & Product Development team, Compliance, Operations, and Financial Partnerships to design robust, secure systems capable of handling real money across fiat and crypto rails.