Peixian Li
Verified Expert in Engineering
Software Engineer and Developer
Redmond, WA, United States
Toptal member since July 14, 2025
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
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
Preferred Environment
Epic, AWS Lambda, Python, Apache Airflow, SMART on FHIR, HL7 FHIR Standard, HL7, TypeScript, PostgreSQL, Amazon DynamoDB
The most amazing...
...project I've led was a seamless referral integration between Epic and Unite Us, using FHIR and AWS serverless architecture to bridge healthcare and social care.
Work Experience
Senior Software and Data Engineer
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.
Staff Software Engineer and Interoperability Lead
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.
Lead Application Developer
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.
Lead Integration Developer
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.
Principal Epic Consultant
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.
Principal Epic Web Service Consultant
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.
Senior Software Developer
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.
Experience
Referral Integration by FHIR
https://uniteus.com/products/closed-loop-referral-system/Education
Master's Degree in Computer Science
University of Virginia - Charlottesville, VA, USA
Bachelor's Degree in Computer Science
Peking University - Beijing, China
Certifications
Epic Data Courier
Epic
Epic Bridges
Epic
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
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring