Senior Software Engineer (Web3 Payments)

We are supporting an APAC-focused technology company building a non-custodial, protocol-level payment infrastructure that enables seamless on-chain settlement for API-based services. The project sits at the intersection of Web3 payments, cryptographic verification, and high-reliability backend systems, with a strong emphasis on security, low latency, and production-grade operations.

This is a greenfield build where senior engineers will help define architecture, security models, and operational standards from day one.

As a Senior Software Engineer, you will take ownership of core backend services that verify cryptographically signed payment requests and coordinate on-chain settlement across multiple blockchain networks. You will work closely with security, compliance, and product stakeholders, and play a key role in shaping system design, reliability practices, and developer experience.

Responsibilities

• Design and implement high-performance backend APIs for payment verification and settlement

• Build cryptographic verification logic (signature validation, replay protection, idempotency)

• Integrate with blockchain RPC providers and design confirmation, retry, and failover strategies

• Architect secure key-management solutions (KMS/HSM), audit logging, and least-privilege access

• Develop chain adapters for EVM and non-EVM networks, starting with stablecoin transfers

• Own production readiness: SLOs, monitoring, alerting, and incident response workflows

• Write technical documentation, threat models, and operational runbooks

• Mentor junior engineers and contribute to engineering standards and best practices

Qualifications

• 5–8+ years of backend engineering experience, ideally in TypeScript/Node and/or Rust

• Strong understanding of cryptographic signatures, structured payloads, and API security

• Hands-on experience with EVM transaction lifecycle (nonce, gas, finality) and/or Solana

• Proven track record building production-grade distributed systems

• Experience with CI/CD, containerised deployments, and observability tooling

• Excellent written communication skills (design docs, threat models, runbooks)

Strongly Preferred

• Experience with payment or settlement systems (idempotency, retries, reconciliation)

• Familiarity with stablecoin transfer patterns (e.g. USDC on EVM chains)

• Background in non-custodial architectures or security-sensitive systems

• Exposure to protocol-level payment flows, API monetisation, or metered billing