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Zi Jing Kang

@zijingkang

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Backend engineer specializing in Scala and ZIO, building data-intensive services with strong production ownership.

Singapore

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What I'm looking for

I’m looking for a backend role where I can own data-intensive services end-to-end—architecture through rollout, observability, and iterative improvement—using Scala/ZIO with strong engineering culture, collaboration, and pragmatic, data-driven decision-making.

I’m a backend software engineer with 6+ years of experience designing and operating data-intensive services in Scala and ZIO. I take ownership end-to-end—from architecture and implementation through rollout, observability, incident investigation, and continued evolution.

At LeadIQ, I architected and became the primary owner of an Email Retrieval Service (ERS), a Scala GraphQL server written in ZIO. I replaced tightly coupled legacy logic with a state monad-inspired service architecture that enabled multiple retrieval strategies, asynchronous workflows, caching, traceable decisions, and independent component evolution.

I design resilient integrations across internal and third-party systems, incorporating concurrency controls, retries, fallback behavior, failure isolation, and production observability. I’ve also investigated throughput bottlenecks and production failure modes using telemetry and large-scale operational datasets, then redesigned processing behavior to improve reliability and resource utilization.

Beyond core services, I built Databricks Spark pipelines and gradient-boosted models (including XGBoost) for contact-data quality, confidence scoring, and domain inference. I’ve also led successors like an Email Verification Service (EVS), and I mentor, onboard, and provide extensive architecture, operations, and onboarding documentation across teams.

Experience

Work history, roles, and key accomplishments

Current

Expert Project Manager (EPM)

Current

Mercor

Dec 2025 - Present (7 months)

Advanced from Writer to Reviewer and Expert Project Manager (EPM), coordinating expert contributors and review workflows across frontier AI training and evaluation projects. Evaluated technical and written outputs, clarified ambiguous requirements, identified recurring quality problems, and provided actionable feedback to improve outcomes.

Experts Coordination Quality Standards Technical Writing Review Quality Problem Identification AI Training And Evaluation

Software Engineer, Backend

LeadIQ

Mar 2022 - Jul 2026 (4 years 4 months)

Architected and became the primary owner of LeadIQ’s Email Retrieval Service (ERS), a Scala GraphQL server written in ZIO, from implementation through company-wide production rollout and ongoing evolution. Replaced legacy logic with a state monad-inspired service architecture and improved reliability via observability-driven redesign of processing behavior.

Scala Zio GraphQL State Monad Inspired Architecture Caching Observability Retries Databricks Apache Spark Domain Inference Circuit Breakers Privacy Aware Logging Metrics Technical Training Code Review

Associate Software Engineer, Backend

LeadIQ

May 2020 - Mar 2022 (1 year 10 months)

Built and maintained Scala backend services and Kafka-based data pipelines supporting LeadIQ’s contact-data and enrichment platform. Developed a ZIO service to process customer-authorized CRM activity, generate structured signals, and publish them to Kafka.

Scala Zio Kafka Backend Services Data Pipelines CRM Activity Processing Data Enrichment Analytics Repository Support

Software Quality Engineer

Rockwell Automation

Mar 2019 - Dec 2019 (9 months)

Served as a software quality engineer for an embedded-software product under Rockwell Automation’s Leadership Development Program, coordinating development and validation activities with cross-functional teams across Singapore, China, and Canada. Improved the internal firmware-release process and standardized validation procedures, presenting to regional and global stakeholders and earning a TÜV R

Software Quality Engineering Cross functional Coordination

Geospatial Information Systems Intern

Hochschule für Technik Rapperswil

Jan 2018 - Jun 2018 (5 months)

Researched and reverse-engineered Google Maps’ Area of Interests behavior and designed an algorithmic approach later implemented by a colleague. Worked with Python and GIS technologies (QGIS, PostGIS, OpenStreetMap) and taught a two-hour Python/QGIS workshop to 30+ participants at GeoPython Conference 2018.

Python QGIS PostGIS OpenStreetMap GIS Reverse Engineering Algorithm Design