Yazhen L.-Backend And Data Engineer
Check rate
Experience
Data Engineer / Data Consultant
Freelance Projects
- Delivered data infrastructure design and performance optimization services for multiple international clients
- Built Spark + Airflow data pipelines on AWS and GCP, balancing cost-efficiency and high availability
- Integrated LLM services such as OpenAI and Gemini to automate text processing and analytics
Backend & Data Engineer (SaaS + AI)
FelixSphere
- Designed and developed backend architecture based on AWS EC2 and RDS, improving system stability and scalability
- Built and optimized GitHub CI/CD pipelines, reducing deployment cycles and release risks
- Implemented Datadog for system monitoring and alerting, significantly reducing incident response time
- Collaborated with frontend and AI teams to build a high-performance, cost-effective intelligent automation platform
- Integrated OpenAI models to enable automated ticket summarization and intelligent responses, enhancing user experience
Data Engineer
Shopee
- Designed star schema data models and multi-layer data warehouse architecture (ODS, DWD, DWS)
- Built automated ETL pipelines to support data collection and cleansing for advertising operations
- Optimized dashboard query performance, reducing latency by approximately 40% and improving data service efficiency
Big Data Engineer
Xiaomi Group · Internet Business Unit, Commercial Big Data Department
Led the development and optimization of Xiaomi's Data Management Platform (DMP), supporting precision marketing, user profiling, and advertising strategy. Spearheaded several key data processing projects across batch, streaming, and scheduling systems.
Key Projects & Achievements:
- User Tagging System
- Built hybrid batch-stream user behavior tagging pipelines using Spark and Flink for efficient processing and real-time updates
- Designed and maintained 25+ user tag categories (e.g., device type, interests, spending power), supporting targeted advertising and user profiling
- Processed over 10TB of log data daily, significantly improving tag coverage and update frequency
- Offline Task Scheduling Optimization
- Designed and implemented a Spark job scheduling service with task state monitoring, retry logic, and dependency management
- Unified five types of heterogeneous tasks under a single scheduling logic, improving maintainability and scalability
- Handled over 1,500 daily jobs, reducing average wait time from 150 minutes to 40 minutes (approx. 67% improvement)
- Real-time Feature Generation Platform
- Built high-throughput real-time feature pipelines using Flink, serving the ad recommendation system
- Leveraged ProcessFunction and Timer to precisely control event windows and state management, achieving millisecond-level latency
- Processed 50K+ user behavior events per second and generated over 1M real-time features per second, significantly enhancing model responsiveness and accuracy
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Information Technology, Professional Services, Advertising, and Retail.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology, Business Intelligence, Marketing, Operations, and Product Development.
Summary
Backend and Data Engineer with 5 years of experience in building high-availability, high-performance data processing systems and backend service architectures. Proficient in big data frameworks such as Spark and Flink, with extensive experience in cloud-native development (AWS/GCP), and hands-on expertise in integrating large language models (LLMs) into production environments.
Skills
- Programming Languages: Java, Scala, Python, Sql
- Big Data & Stream Processing: Spark, Flink, Kafka, Hbase, Hive, Hadoop
- Data Engineering: Etl Pipeline Design, Star Schema Modeling, Data Quality Management
- Workflow & Orchestration: Airflow
- Cloud Platforms: Aws, Gcp, Databricks
- Ai/Llm Integration: Practical Experience Integrating Openai, Gemini, And Other Llm Services Into Production Systems
Languages
Education
Hunan Normal University
Bachelor of Science · Computer Science and Technology · Chang Sha Shi, China
Statistics
Experience
Global experience
Expertise
Qualifications
Profile
Frequently asked questions
Have questions? Find more information here.
Yazhen is based in Changsha, China and can operate in on-site, hybrid, and remote work models.
Yazhen speaks the following languages: Chinese (Native), English (Intermediate).
Yazhen has at least 5 years of experience. During this time, Yazhen has worked in at least 4 different roles and for 4 different companies. The average length of individual experience is 1 year and 4 months. Note that Yazhen may not have shared all experience and actually has more experience.
Based on recent experience, Yazhen would be well-suited for roles such as: Data Engineer / Data Consultant, Backend & Data Engineer (SaaS + AI), Data Engineer.
Yazhen's most recent position is Data Engineer / Data Consultant at Freelance Projects.
In recent years, Yazhen has worked for Freelance Projects, FelixSphere, Shopee, Xiaomi Group · Internet Business Unit, and Commercial Big Data Department.
Yazhen is most experienced in industries like Information Technology, Professional Services, and Advertising. Yazhen also has some experience in Retail.
Yazhen is most experienced in business areas like Information Technology, Business Intelligence, and Marketing. Yazhen also has some experience in Operations and Product Development.
Yazhen holds a Bachelor in Computer Science and Technology from Hunan Normal University.
Yazhen is immediately available full-time for suitable projects.
Daily rate distribution
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Average rates for similar positions
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The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 6 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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