Senior Backend Engineer

Alex Chen

Specializing in Node.js, PostgreSQL, system modernization, and Fintech backend systems.

View Experience
Alex Chen
About me

Senior backend engineer.
Fintech systems builder.

Senior Backend Engineer with 9 years of experience specializing in Node.js (Nest.js / Express) and PostgreSQL. Proven expert in system modernization, having spearheaded 150+ API migrations that delivered a 33% performance boost and supported 400% DAU growth. Deeply versed in the Fintech sector, I possess a strong track record in building KYC / AML systems and OAuth2 / JWT services while ensuring absolute financial data integrity. A proactive self-starter with an enterprise foundation from Microsoft and Trend Micro, I leverage observability (Sentry / CloudWatch) to independently resolve production issues and drive engineering excellence through type-safety (Zod) and automated testing.

Tech Stack

Tools I work with

Backend
Node.jsExpress.jsNest.jsJava Spring BootASP.NET Core
Data & Security
PostgreSQLMySQLRedisCachingRate LimitingPrismaKYC / AML IntegrationOAuth2JWTRBACOWASP Security
Ops & AI
AWSCloudWatchSentryKibanaDockerEC2LambdaS3LangChainAWS BedrockRAGFAISSPrompt Engineering
Career

Experience

Feb 2024 — Present
Senior Software Engineer
Mammoth Cyber — Spearheaded migration of 150+ core APIs to a structured Node.js / Nest.js architecture, delivering a 33% performance boost while supporting 400% DAU growth. Established production monitoring with AWS CloudWatch and Sentry, designed a BFF layer and GraphQL APIs, optimized PostgreSQL schemas, and engineered FastAPI / LangChain RAG pipelines while mentoring junior engineers.
Jul 2022 — Feb 2024
Full-Stack Engineer
Trend Micro — Introduced RabbitMQ with Dead Letter Queue handling to offload asynchronous tasks and improve API response times by 120%. Developed a JWT / OAuth2 Token Exchange Service in Node.js and Java to bridge modern services with legacy systems, and led Module Federation work to integrate legacy and modern React applications.
Apr 2021 — Jun 2022
Software Engineer
XREX — Translated complex AML regulations into scalable backend architectures. Integrated TRM Labs and handled KYC workflows for thousands of crypto exchange users, while ensuring 100% data consistency for high-concurrency financial transactions with Java Spring Boot, MySQL, and transaction isolation controls.
Apr 2020 — Apr 2021
Software Engineer
HP — Developed an ERP backend using ASP.NET Core and EF Core based on Clean Architecture. Designed a visual query builder for PC parts inventory so PMs could perform validated queries without writing SQL.
Jul 2017 — Jul 2019
R&D Intern
Microsoft Corporation — Independently developed an API Management Platform PoC using ASP.NET Core and Identity Server, which was adopted as a sales demonstration project.