Senior Software Engineer (Web3 Payments)
Skills
About the role
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
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