Codex - Software Engineer

• Financial Partner Integrations • Own integrations with banks, payment providers, and liquidity venues end-to-end — from API contract and webhook design through to production hardening and reconciliation • Build integrations that are robust to vendor reality: incomplete documentation, schema changes without warning, and validation rules that shift post-go-live • Build messaging / notification systems with signature verification and replay protection; pin schemas against real sandbox behaviour; design for failure at every layer • Maintain and evolve the reconciliation layer across all connected payment rails — fees, settlement windows, and exception handling as first-class concerns • Operational Automation • Identify manual workflows in onboarding, compliance, and back-office operations and systematically replace them with product and automation • Enable self-service for internal ops teams and customers, reducing engineering dependency for routine operational tasks • Work closely with Compliance and Operations to understand where the friction is and build the tooling that removes it • Treasury & Liquidity Automation • Design and build the automation layer for Codex's trading and treasury operations — automated position management, liquidity routing, and risk controls • Design for failure: clear handling of automated decision failures, position unwinding, and safe degradation • Engineering Standards • Set and maintain the engineering standard for how payment integrations are built at Codex — idempotency, audit trails, fail-closed design, exact decimal arithmetic, and deterministic durable orchestration • Mentor engineers on the hard parts of money movement systems • Continuously design and build for security, hardening our systems • Ship and critically review AI-assisted code with the judgement to identify plausible but incorrect output or output detrimental to a product’s long-term health and sustainability