Hongzhe Xie
Full-Stack Software Engineer
I build secure web platforms, identity systems, and AI agents. At UC Merced, I operate a production platform connecting capstone teams with industry sponsors.
Selected work
TokenRouter — One gateway for multiple AI providers, with secure routing and concurrency-safe token accounting.
The problem
Applications need one gateway for different AI provider protocols, with usage accounting that stays consistent when requests overlap or fail.
What I built
Built an OpenAI-compatible LLM gateway that converts between provider protocols, routes by priority and weight with failure-aware retries, and reserves and settles token quotas concurrency-safely.
An engineering decision
User and API-token quota holds are paired in one database transaction. Settlement and refunds are idempotent, and durable reservation records keep failed operations available for reconciliation.
Evidence in the code
The test suites cover atomic settlement, repeated settlement and refunds, rollback on failure, and concurrent reservations that cannot overspend.
MobileID — A Django/Vue identity platform with barcode workflows and control over sessions on other devices.
The problem
A mobile identity application needs barcode and profile workflows alongside control over authenticated sessions on other devices.
What I built
Built a Django/Vue identity platform for PDF417 barcode generation, profile management, and device-aware sessions on PostgreSQL and DynamoDB.
An engineering decision
Cookie-based JWT authentication combines refresh-token blacklisting with access-session revocation checks on subsequent API requests. Cookie-authenticated writes also require CSRF validation.
Evidence in the code
Tests cover device listing, revoking one or all other devices, rejection of revoked access tokens, and CSRF enforcement. CI configures a 70% backend coverage floor alongside security checks and Playwright suites.
Experience
Full-Stack Software Engineer
School of Engineering, University of California, Merced · Oct 2025 - Present
- Architected and now operate the program's official production platform (Django REST Framework, React 19 + TypeScript + Vite), which runs partner intake, team matching, and milestone tracking for capstone collaborations between industry sponsors and student teams.
- Built the platform's block-based CMS, registration flow, barcode ticketing, and check-in, giving staff an auditable trail of every administrative action.
- Designed a dual-tier agentic workflow separating authenticated admin operations from read-only public event queries, isolated by RBAC, bounded context, per-IP token budgets, and privilege-escalation guards.
- Built an AI-assisted phishing detector validating SPF/DKIM/DMARC and sender alignment plus punycode, typosquat, and URL heuristics, with Amazon Bedrock review over a deterministic rules-only fallback.
- Mentor undergraduate teams on scoping, system design, and code review, holding student work to production standards for industry sponsors.
Computer Vision / AI Engineering Intern
China Academy of Building Research · Jul 2023 - Oct 2023
- Built a Python semantic-segmentation pipeline that identifies deployable rooftop photovoltaic area in aerial imagery of rural villages.
- Annotated and curated the training dataset, then converted segmented rooftop area into estimated annual solar generation capacity.
Education
University of California, Davis
Davis, CA · Expected May 2028
University of California, Merced
Merced, CA · Computer Science and Engineering · Major GPA 3.992/4.0
Additional
Citigroup Financial Investment Analysis Training Program · Jul 2023. Selective cohort; built Excel and Python models for company-performance analysis.
Conferences: Google Cloud Next 2026; Google I/O 2025; Microsoft AI Day 2024