Peixian is available for hire
Hire PeixianPeixian Li
Verified Expert in Engineering
Software Engineer and Developer
Redmond, WA, United States
Toptal member since July 14, 2025
Bio
Peixian is a seasoned software and data engineer with 20+ years of experience in healthcare, specializing in electronic health record (EHR) data interoperability, back-end API services, and data pipelines. Drawing on deep expertise in Epic, Fast Healthcare Interoperability Resources (FHIR), and healthcare data, he helps teams deliver reliable, high-impact solutions across cloud and on-premise environments. Committed to advancing healthcare technology, Peixian drives innovation and efficiency.
Portfolio
DexCare Health
TypeScript, Python, Amazon Managed Workflows for Apache Airflow (MWAA)...
Unite US
Amazon DynamoDB, Amazon API Gateway, Amazon Simple Notification Service (SNS)...
Aim Consulting
JavaScript, Serverless Framework, Amazon DynamoDB, AWS Lambda...
Experience
- Software Design - 20 years
- Epic - 20 years
- HL7 - 18 years
- SMART on FHIR - 6 years
- AWS Lambda - 6 years
- Fast Healthcare Interoperability Resources (FHIR) - 6 years
- TypeScript - 5 years
- Python - 3 years
Work Experience
Senior Software and Data Engineer
2022 - 2025
DexCare Health
- Developed serverless infrastructure using TypeScript, Koa, and AWS Lambda as a founding data engineer, enabling rapid deployment of secure, reusable APIs that powered Airflow-orchestrated data pipelines.
- Built a back-end SMART on FHIR app integrated with Epic to fetch patient data, including conditions, encounters, and EOBs. Linked this data to DexCare-scheduled visits, enabling machine learning models to improve scheduling accuracy and provider utilization.
- Designed and built a scalable analytics pipeline using Ably and AWS Lambda to ingest events into a data warehouse, with an extensible schema supporting future event types and analytics use cases.
- Spearheaded data ingestion pipelines for onboarding the two most complex customers, orchestrating data retrieval and transformation with Airflow, and unifying ingestion into core systems using AWS Step Functions.
Technologies: TypeScript, Python, Amazon Managed Workflows for Apache Airflow (MWAA), Apache Airflow, AWS Lambda, AWS Step Functions, PostgreSQL, Pydantic, SMART on FHIR, HL7, HL7 FHIR Standard, Express.js, Ably, RabbitMQ, Datadog, Splunk, Serverless Framework, React, Kubernetes, Koa, SQL, Data Engineering, AWS ECS Fargate
Staff Software Engineer and Interoperability Lead
2021 - 2022
Unite US
- Served as staff engineer and lead of the interoperability team, collaborating with Epic and Kaiser on a groundbreaking project that established closed-loop referral integration between healthcare and social care systems.
- Oversaw a newly formed six-person interoperability team, working cross-functionally with leadership, product, and Epic on design, development, and testing. Earned CEO recognition and was converted to full-time employee within one month.
- Collaborated with the core team to design and implement patient matching and creation, critical for processing incoming referrals from Epic.
Technologies: Amazon DynamoDB, Amazon API Gateway, Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Amazon Virtual Private Cloud (VPC), Ruby, SMART on FHIR, OAuth 2, Fast Healthcare Interoperability Resources (FHIR), New Relic, Amazon CloudWatch, Serverless Framework, Epic Systems, Referrals
Lead Application Developer
2020 - 2021
Aim Consulting
- Orchestrated a consulting team to design, develop, and deploy a FHIR server and APIs for Medinformatix, enabling no-contact pre-visit check-ins via their mobile app during the COVID-19 pandemic.
- Guided the team to develop and deploy a prior authorization update API, enabling receipt and processing of authorization request updates.
- Applied deep EHR data expertise and thorough source database analysis to drive data mapping and discovery, uncovering critical insights early in the process.
Technologies: JavaScript, Serverless Framework, Amazon DynamoDB, AWS Lambda, Amazon API Gateway, Amazon Cognito, Microsoft SQL Server
Lead Integration Developer
2015 - 2020
Overlake Medical Center & Clinics
- Collaborated with consultants as integration tech lead to deliver over 80 Workday integrations across human capital management, finance, and supply chain, including a Health Level Seven (HL7) interface with Epic for surgical supply inventory.
- Developed a single-page web app using ASP.NET, AngularJS, and Bootstrap to track real-time urgent care wait times, enhancing patient experience by providing timely updates.
- Built and maintained more than 50 HL7 interfaces, including admission, discharge, and transfer (ADT), orders, vital signs, cardiology, radiology, and laboratory results.
- Partnered with Apple to establish FHIR integration with the Apple Health app, enabling seamless access to medical data through FHIR APIs.
Technologies: HL7, Fast Healthcare Interoperability Resources (FHIR), Epic Bridge, Summit Interface Engine, Workday, AngularJS, ASP.NET, Bootstrap, HTML, CSS, Epic Interconnect
Principal Epic Consultant
2011 - 2014
Cleveland Clinic
- Drove system-wide, code-based data reconciliation during a major deployment merge, flawlessly consolidating thousands of Epic custom configurations with source codes and resolving critical data discrepancies, resulting in zero go-live errors.
- Enhanced hematology and oncology scheduling SmartForm and InBasket print groups. Developed a new bone marrow transplant (BMT) SmartForm with print groups, navigation menus, and sections for seamless integration into the Hyperspace Visit Navigator.
- Analyzed hardcoded ICD-9 codes in custom source codes, extension (LPP), and print group (LPG) records; migrated them to VCG groupers, rewrote code to utilize VCG, and mapped ICD-9 to ICD-10 for large VCG groupers.
Technologies: Epic Systems
Principal Epic Web Service Consultant
2009 - 2010
Kaiser Permanente
- Designed and implemented 60 SOAP-based SOA web services in C#.NET with a team of three to retrieve patient data from Epic, including demographics, encounters, orders, medications, vitals, allergies, problem lists, providers, notes, and ADT events.
- Integrated compliance and security filters into web services to prevent unauthorized access to sensitive data, including orders, notes, diagnoses, transcriptions, and encounters, for special patients and departments.
- Added versioning support to APIs, enabling multiple versions for internal web applications and ensuring backward compatibility for smooth transitions between updates.
Technologies: SOAP APIs, SoapUI, Epic Interconnect, C#.NET, Web Services
Senior Software Developer
2001 - 2009
Epic
- Delivered core infrastructure and key features of EMFI version 1 at an accelerated pace. This leveraged Epic's HL7 messaging to automate data synchronization across deployments and ensure availability and consistency for large multi-deployment customers.
- Co-developed the initial version of Data Courier, a manual tool branched from EMFI for migrating build data across internal environments; widely adopted by customers and awarded US Patent 8,825,502 for its innovative design.
- Contributed to the design and development of Clinical Pathways, a product standardizing care for medical conditions with similar treatments across patients. Drove its integration with key Epic applications.
- Served as the team's Clarity point person by maintaining SQL tables and columns, writing KB_SQL queries to extract data, and updating Crystal Reports to meet reporting needs.
Technologies: Epic Systems, Epic Chronicles, MUMPS, C#.NET, Visual Basic 6 (VB6), Epic Bridges, Epic Clarity, Epic Clinical Data Model, Epic Inpatient, Epic Data Courier, SQL
Project History
Referral Integration by FHIR
https://uniteus.com/products/closed-loop-referral-system/I served as staff engineer and lead of the interoperability team, collaborating with Epic and Kaiser on a groundbreaking project that established closed-loop referral integration between healthcare and social care.
Education
1999 - 2001
Master's Degree in Computer Science
University of Virginia - Charlottesville, VA, USA
1995 - 1999
Bachelor's Degree in Computer Science
Peking University - Beijing, China
Certifications
OCTOBER 2014 - PRESENT
Epic Data Courier
Epic
OCTOBER 2014 - PRESENT
Epic Bridges
Epic
SEPTEMBER 2001 - PRESENT
Epic Chronicles Developer
Epic
Skills
Libraries/APIs
Pydantic, React, SOAP APIs
Tools
SMART on FHIR, Apache Airflow, AWS Step Functions, RabbitMQ, Splunk, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Amazon Virtual Private Cloud (VPC), Amazon CloudWatch, Amazon Cognito, SoapUI
Languages
Python, TypeScript, MUMPS, Ruby, JavaScript, HTML, CSS, C#.NET, Visual Basic 6 (VB6), SQL
Paradigms
HL7 FHIR Standard, Fast Healthcare Interoperability Resources (FHIR), Epic Clinical Data Model
Platforms
AWS Lambda, Epic Chronicles, Ably, Kubernetes, New Relic, Epic Clarity
Storage
PostgreSQL, JSON, Amazon DynamoDB, Datadog, Microsoft SQL Server
Frameworks
Express.js, Serverless Framework, Koa, OAuth 2, AngularJS, ASP.NET, Bootstrap
Other
Epic, HL7, Software Design, Epic Systems, Data Mapping, Computer Science, Algorithms, Mathematics, Intrusion Detection Systems (IDS), Epic Content Management, Amazon Managed Workflows for Apache Airflow (MWAA), Amazon API Gateway, Referrals, Epic Bridge, Summit Interface Engine, Workday, Epic Interconnect, Web Services, Epic Bridges, Epic Inpatient, Epic Data Courier, Data Engineering, AWS ECS Fargate
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