Senior Payments Platform Engineer - Full-Stack

CashJar.com; Metro Manila; On-site; PHP 900,000 - 1,500,000; Full time

Benefits offered by this job

Competitive salary

Remote work

Professional development

Job summary

OutsideHire is seeking a Senior Fullstack Engineer - Payments to build the payment SDK and supporting services. You will implement hosted-fields integration, gateway-agnostic APIs, and a robust client-side state model.

The role covers both frontend and backend work with a strong emphasis on security and correctness. You will own session routing, tokenization, idempotent flows, and webhook/reconciliation logic, ensuring reliable processing for live merchants.

Qualifications

• 7+ years building production software across frontend and backend.
• Deep experience with React and TypeScript, including rendering behavior and component APIs.
• Strong backend with API contracts and architecture discussions (.NET stack).
• Payment systems experience including gateways, tokenization, webhooks, and reconciliation.
• Security fundamentals: same-origin policy, CSP, CORS, XSS, iframe isolation, secrets handling.
• Agentic AI tools in daily workflow (Claude/ Codex/ Cursor).
• Testing discipline and writing tests for payment code.

Responsibilities

• Build the payment SDK and client layer with hosted-fields and a gateway-agnostic API.
• Develop the payment services: session routing, tokenization, idempotency, webhooks, and reconciliation.
• Build the platform around it: versioning, deprecation, observability, and developer experience.

Skills

React

TypeScript

.NET

API design

Security fundamentals

Testing

Observability

Tools

Hosted fields

Gateway APIs

CI/CD

Azure/AWS

PCI DSS knowledge

Job description

OutsideHire is seeking a Senior Fullstack Engineer - Payments to build the payment SDK and supporting services. You will implement hosted-fields integration, gateway-agnostic APIs, and a robust client-side state model.

The role covers both frontend and backend work with a strong emphasis on security and correctness. You will own session routing, tokenization, idempotent flows, and webhook/reconciliation logic, ensuring reliable processing for live merchants.